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Re: [loopantennas] Re: The Tale of three Chinese Loops - comparison and pictures

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  • Jay Heyl
    ... You haven t really described how you re testing the loops. For MW, the testing should be done during the day, preferably in the early afternoon. Skywave
    Message 1 of 23 , Jul 12, 2008
      On Sat, Jul 12, 2008 at 2:58 AM, gmcjetpilot <gmcjetpilot@...> wrote:

      >
      > ** TEST CONTINUES **
      >
      > Since I last wrote, I tried all three loops with my Degen DE1103. The
      > Degen must be maxed out already with the existing internal loop
      > stick, because none of the loops produce a significant gain. The
      > DE1103 does have an antenna jack input but not for MW, only for SW.
      > I'll try the MW loops on 160 meter.
      >

      You haven't really described how you're testing the loops. For MW, the
      testing should be done during the day, preferably in the early afternoon.
      Skywave reception at night makes accurate testing virtually impossible. In
      the day time you're getting almost all ground wave, which will not vary
      significantly during the time of the test.

      To test gain, find a station that's just barely perceptible on the radio
      with the internal antenna. Even better, tune to a station you know is there
      but is just out of range on the barefoot radio. This gives you enough head
      room to get some idea of how much gain the antennas are providing.

      Another important characteristic of a MW antenna is the ability to null
      interfering stations. For this you need to find a fairly strong station
      that's masking another station. Rotate the antennas until the strong station
      begins to fade. Keep adjusting to minimize the strong station. Can you know
      get a decent signal from the station that was masked? The masked station
      will need to be at an angle to the stronger station. The closer to 90
      degrees, the easier it will be to null one and receive the other.

      Finally, the sharpness of the null produced by an antenna can be an
      important characteristic. For this you need to find two interfering stations
      that form a fairly narrow angle from your location. You'll probably have to
      experiment to find a situation where at least one of the antennas makes a
      difference in reception and compare the others to that.

      Hope this helps.

      -- Jay


      [Non-text portions of this message have been removed]
    • airchecklover
      ... George; Nice job reporting test results. I need to embellish my statement about the Tecsun having many many turns (I was tired and did not say it
      Message 2 of 23 , Jul 12, 2008
        --- In loopantennas@yahoogroups.com, "gmcjetpilot" <gmcjetpilot@...>
        wrote:
        >
        > --- In loopantennas@yahoogroups.com, "airchecklover" <mdh@> wrote:
        > >
        > >
        > > > Can any one tell my why the Tecsun tuning is more mellow and
        > seems
        > > > less sensitive or wider sweet spot? It is affective but different
        > > > than the Terk which is like the TG34, very sharp null and sweet.
        > > >
        > >
        > > An educated guess says the Tecsun is not as sharp because they used
        > > (from looks of picture) many many turns of small gauge wire. They
        > > probably chose this approach for aesthetic appeal (sure looks good
        > > doesn't it) because it actually works against the performance of the
        > > antenna.
        > >
        >
        > ** TOO MANY TURNS **
        >
        > ???????? "many many turns of small gauge wire" ????????
        >
        > It has 28 turns, which is about right according to the Loop Antenna
        > Calculator.
        >
        > I just noticed on the inside of the loop there are three turns in the
        > middle, under the induction winding; this must be the sense wire for
        > the direct connection.
        >
        > You say too many turns of small gage wire? Does wire gage have
        > anything to do with it? If limited to 9" dia loop than how many turns
        > do you need? With the loop calculator a 10-365 pf cap 28 turns gives
        > 550 Khz -3380 Khz around a 7" x 7" frame (the calculator is for
        > square loops, so 7"x7" is equiv to 9" round in circumference or wire
        > length per turn).
        >
        > I wounder what the TERK has inside. There are screws to disassemble
        > but something tells me not to to take this one apart.
        >
        >
        >
        > ** TUNING SENSITIVITY **
        >
        > I have to say the Tecsun AN-200 has about the same gain as the Terk
        > in performance, from what I can tell. I am hard pressed to say there
        > is a big difference between the two passive loops. It is just that
        > the Tecsun has a less sharp edge tuning characteristic. I don't want
        > to say less sensitive, just not AS SENSITIVE to tuning the CAP.
        >
        > Speaking of tuning sensitivity, the TG34 active loop is SUPER
        > SENSITIVE and with a tiny thumbnail tuning dial, it takes a precise
        > touch to get it dialed in.
        >
        >
        >
        >
        > ** TEST CONTINUES **
        >
        > Since I last wrote, I tried all three loops with my Degen DE1103. The
        > Degen must be maxed out already with the existing internal loop
        > stick, because none of the loops produce a significant gain. The
        > DE1103 does have an antenna jack input but not for MW, only for SW.
        > I'll try the MW loops on 160 meter.
        >
        > I also revisited the Sony AM/FM portable/table radio. All loops
        > produce obvious and some times dramatic difference. I got the TG34
        > out for side-by-side comparison to the passive loops.
        >
        >
        > ** UPDATED CONCLUSION SO FAR **
        >
        > As I thought and remembered, the TG34 does a little better with its
        > amplification and loop-stick repeater for "proximity" signal boosting
        > on the Sony table AM radio. The down side are the exta wires and
        > trying to position the soft loop in the window, which can be a pain.
        > Some stations are better with the loop perpendicular to the window (N-
        > S), other stations are better with loop flush to the window (E-W)
        > direction. I have to jury rig a support out from the top of the
        > window to hang the loop from, than tether to keep it from turning.
        >
        > Tuning sensitivity of the TG34 with a small thumbnail dial on the
        > small amplifier module (the size of a large pack of gum) makes tuning
        > more touchy and harder than the others, at least with out practice.
        > Its easy to overshoot (again). Very small movement of tuning dial
        > makes a big difference. Of course the TG34 can do SW and is pretty
        > good up to about 9-13Mhz.
        >
        > The passive loops are just right for the portable or table top AM
        > radio on a table. They are both nice, the Terk AM advantage and
        > Tecsun AN-200 are worth a look. I'm probably going to keep both, and
        > if have to decide on one, the choice would be hard. I would lean more
        > towards the Terk only because it comes with a better cord to connect
        > to radio and may be (?) a tad bit more gain (may be). However style
        > wise, the Tecsun AN-200 is pretty flashy. If the wife is involved
        > this would be a good one for her to decide based on style aesthetics
        > alone, since they perform pretty close.
        >
        > MORE test to come? I'll keep you posted if I find anything else.
        >
        > Cheers George
        >

        George;

        Nice job reporting test results. I need to embellish my statement
        about the Tecsun having many many turns (I was tired and did not say
        it correctly).

        I've only built larger loops, starting at 2 ft. They need 15 turns or
        so for a std. 15pf-360pf capacitor. 28 turns seems like alot but given
        it resonates, the number of turns is obviously matched with the
        correct value variable capacitor. A possible reason why the "Q" is low
        and tuning is wide is because the turns are very close together. It is
        a known fact inter-winding capacitance plays a role in loops and Q is
        reduced (ie, bandwidth is wider) with closer spacing of windings. As
        to why the Terk's bandwidth is tighter than the Tecsun, given the
        width of the loops appears to be about the same - I don't know without
        seeing the windings. One possibility is the Terk uses Litz wire which,
        by it's design, reduces inter-winding capacitance.

        Keep us posted if you take the Terk apart.

        Mark
      • gmcjetpilot
        Hi Mark: Roger that, the turns are close together (touching) and clearly spreading them out improves the low end. I just did my final test this time with a Ten
        Message 3 of 23 , Jul 12, 2008
          Hi Mark:

          Roger that, the turns are close together (touching)
          and clearly spreading them out improves the low end.

          I just did my final test this time with a Ten Tec
          RX320D (PC radio).

          Using the S-meter was better. I ran all of them
          through a 30:1 balun.

          I also compared the three loops to may main
          antenna, a 60 foot random wire, approx 15-20 feet
          above ground, with 30:1 balun, grounded of course.

          The pecking order (MW band) is:

          Random wire
          TG34 amplified loop
          Terk Am Advantage
          Tecsun AN-200


          The random wire is better than the TG34 and both
          passove loops. The random wire random wire is
          significantly better than the two passive loops.
          The TG34 was also much better than the two passive
          loops.

          The two passive loops are close, but clearly of the
          two passive table top loops, the Terk has a bit more
          uhumph, based on my S-meter. Sound wise it was
          hard to tell, but on one station I though the Terk had
          lower noise or static.

          Surprisingly the random wire was more quiet, at
          least on the few stations I checked, but not always.
          Keeping in mind the random wire is outside and the two
          loops I had in a 2nd floor window sill, but near by CRT
          computer monitor, which no doubt added noise.

          Conclusion loops are awesome but just one tool in
          the antenna bag of tricks.

          My next antenna actually will be a 2' x 2' loop on
          an "X" frame. I just got the air capacitor in the
          mail. I expect to blow the 9" loops away. Bigger is
          better.

          One day I'll have room for a real long wire and/or a
          Wellbrook Loop on a rotor.

          Thanks for the input.

          George



          >--- "airchecklover" <mdh@...> wrote:
          >
          > George;
          >
          > Nice job reporting test results. I need to
          >embellish my statement about the Tecsun having
          >many many turns (I was tired and did not say
          >it correctly).
          >
          > I've only built larger loops, starting at 2 ft. They
          >need 15 turns or so for a std. 15pf-360pf
          >capacitor. 28 turns seems like alot but given it
          >resonates, the number of turns is obviously
          >matched with the correct value variable capacitor.
          >A possible reason why the "Q" is low and tuning
          >is wide is because the turns are very close
          >together. It is a known fact inter-winding
          >capacitance plays a role in loops and Q is reduced
          >(ie, bandwidth is wider) with closer spacing of
          >windings. As to why the Terk's bandwidth is
          >tighter than the

          >Tecsun, given the width of the loops appears to be
          >about the same - I don't know without seeing the
          >windings. One possibility is the Terk uses Litz
          >wire which, by it's design, reduces inter-winding
          >capacitance.
          >
          > Keep us posted if you take the Terk apart.
          >
          > Mark
        • airchecklover
          ... George; Sounds like you are having fun :) Couple thingies to pass on ... a) I have found a practical limit to bigger is better .... my 2 ft loop (15
          Message 4 of 23 , Jul 13, 2008
            --- In loopantennas@yahoogroups.com, "gmcjetpilot" <gmcjetpilot@...>
            wrote:
            >
            > Hi Mark:
            >
            > Roger that, the turns are close together (touching)
            > and clearly spreading them out improves the low end.
            >
            > I just did my final test this time with a Ten Tec
            > RX320D (PC radio).
            >
            > Using the S-meter was better. I ran all of them
            > through a 30:1 balun.
            >
            > I also compared the three loops to may main
            > antenna, a 60 foot random wire, approx 15-20 feet
            > above ground, with 30:1 balun, grounded of course.
            >
            > The pecking order (MW band) is:
            >
            > Random wire
            > TG34 amplified loop
            > Terk Am Advantage
            > Tecsun AN-200
            >
            >
            > The random wire is better than the TG34 and both
            > passove loops. The random wire random wire is
            > significantly better than the two passive loops.
            > The TG34 was also much better than the two passive
            > loops.
            >
            > The two passive loops are close, but clearly of the
            > two passive table top loops, the Terk has a bit more
            > uhumph, based on my S-meter. Sound wise it was
            > hard to tell, but on one station I though the Terk had
            > lower noise or static.
            >
            > Surprisingly the random wire was more quiet, at
            > least on the few stations I checked, but not always.
            > Keeping in mind the random wire is outside and the two
            > loops I had in a 2nd floor window sill, but near by CRT
            > computer monitor, which no doubt added noise.
            >
            > Conclusion loops are awesome but just one tool in
            > the antenna bag of tricks.
            >
            > My next antenna actually will be a 2' x 2' loop on
            > an "X" frame. I just got the air capacitor in the
            > mail. I expect to blow the 9" loops away. Bigger is
            > better.
            >
            > One day I'll have room for a real long wire and/or a
            > Wellbrook Loop on a rotor.
            >
            > Thanks for the input.
            >
            > George

            George; Sounds like you are having fun :)

            Couple thingies to pass on ... a) I have found a practical limit to
            "bigger is better" .... my 2 ft loop (15 turns of 20 ga (or is it 22
            ga) solid copper is my best BCB loop 9 out of 10 times as opp to my
            3.5 ft loop. Why? Combination of ease of use (rotation/placement) and
            enough gain to grab the really weak ones (daytime signals). The big
            loop with much bigger aperture and more gain seems to hit a theretical
            point of "no more returns" at my QTH where residual noise becomes the
            bigger issue. Have I "maxxed out" for my QTH? Perhaps. But maybe
            not. I've yet to get my end-fed sloper up - perhaps that will surprise
            me. But what really surprised me was this setup: I have a CCrane
            Twin-Ferrite as well as the 2 ft loop and 3.5 ft loop. Each on it's
            own gives me a significant gain and better s/n ratio on BCB than a
            barefoot radio. I'd been using inductive coupling with the loops,
            direct coupling with the T-F. One day I got a little crazy and
            direct-connected the T-F, setting its ferrite head next to the 2 ft
            loop which was sitting on a Lazy Susan. --> YES!!!!!! <--
            The sum betters each individual contribution. I am now getting more
            gain & improved s/n ratio using a combo of the two antennas. I mostly
            spin the loop for direction but sometimes orienting the T-F head and
            playing it's sweet/null points against the loops seems to give me more
            null options. At any rate, this is a DX setup and not too gangly and
            unwieldy. Perhaps someday I'll have a chance to put this setup
            against a Quantum to see how it fairs for gain and null. The Quantum,
            with it's Q multiplier, will always win in the Q department.


            b) I wonder about the performance difference between loops and long
            wire and the 30:1 balun. I'm still attempting to become an antenna
            expert (I'll let you know if/when I ever get there :) but from
            reading, most end-fed long wires use a balun ranging from 4:1 to 9:1.
            30:1 seems like a huge ratio. Can you elaborate on that? Is this a
            store-bought or a home brew antenna? Did you wind the balun? Where
            did you get plans?

            And I wonder about using the 30:1 balun with your loops. They both
            have sense loops for direct-connect, correct? Wouldn't
            direct-connecting yield more gain? Or is your rcvr loading down the
            sense loop so you've connected a balun in between? I ask also because
            I have a TG 34 and although I've never done a side-by-side with a BCB
            loop, it never struck me as being as good a BCB antenna compared to
            the multi-turn passive loops. Hmmm. Maybe I need to re-evaluate? Or
            is the use of a 30:1 balun with the Terk & Tecsun hurting performance?

            Hope you can post more results. Good so far.

            Mark
          • Fraser
            ... Just read this and was interested to see the results. Only a couple of comments on this test though.... 1. I am not sure what was meant by the comment
            Message 5 of 23 , Jul 13, 2008
              --- In loopantennas@yahoogroups.com, "gmcjetpilot" <gmcjetpilot@...>
              wrote:
              >
              > Hi Mark:
              >
              > Roger that, the turns are close together (touching)
              > and clearly spreading them out improves the low end.
              >
              > I just did my final test this time with a Ten Tec
              > RX320D (PC radio).
              >
              > Using the S-meter was better. I ran all of them
              > through a 30:1 balun.
              >
              > I also compared the three loops to may main
              > antenna, a 60 foot random wire, approx 15-20 feet
              > above ground, with 30:1 balun, grounded of course.
              >
              > The pecking order (MW band) is:
              >
              > Random wire
              > TG34 amplified loop
              > Terk Am Advantage
              > Tecsun AN-200
              >
              >
              > The random wire is better than the TG34 and both
              > passove loops. The random wire random wire is
              > significantly better than the two passive loops.
              > The TG34 was also much better than the two passive
              > loops.
              >
              > The two passive loops are close, but clearly of the
              > two passive table top loops, the Terk has a bit more
              > uhumph, based on my S-meter. Sound wise it was
              > hard to tell, but on one station I though the Terk had
              > lower noise or static.
              >
              > Surprisingly the random wire was more quiet, at
              > least on the few stations I checked, but not always.
              > Keeping in mind the random wire is outside and the two
              > loops I had in a 2nd floor window sill, but near by CRT
              > computer monitor, which no doubt added noise.
              >
              > Conclusion loops are awesome but just one tool in
              > the antenna bag of tricks.
              >
              > My next antenna actually will be a 2' x 2' loop on
              > an "X" frame. I just got the air capacitor in the
              > mail. I expect to blow the 9" loops away. Bigger is
              > better.
              >
              > One day I'll have room for a real long wire and/or a
              > Wellbrook Loop on a rotor.
              >
              > Thanks for the input.
              >
              > George
              >
              >
              >

              Just read this and was interested to see the results. Only a couple
              of comments on this test though....

              1. I am not sure what was meant by the comment "Using the S-meter was
              better. I ran all of them through a 30:1 balun."

              The TG34 has an output impedance of approx 50 Ohms so why would you
              put it into an impedance transformer ? (30:1 is one heck of an
              impedance change)


              2. Why was the S-Meter the measurement tool of choice ? An S-Meter
              does not deliver a Signal to Noise ratio indication. It is well known
              that Loops, active or passive, often produce less Signal strength but
              that really is not the point. The signal to noise ratio is the key
              performance indicator, provided the loop produces enough RF output to
              overcome the noise floor of the receiver. Most modern HF receivers
              are quiet enough and have enough AGC range to cope with the low RF
              output of a decent loop. It is also worth noting that the Ten-Tec
              is "hobbled" on frequencies below 2 MHz as a feature of it's design
              so sensitivity is greatly reduced (I own an RX320 as well)

              Jut some food for thought and don't forget that when comparing a long
              wire aerial (antenna) with a loop, you are comparing E field and an H
              field aerials ..... they behave totally differently when placed in
              noisy (i.e domestic) RF environments ;-)

              Best Wishes

              Fraser
            • Jim Dunstan
              ... Hi Mark, The multi-inductor (loop) front end is superior to most single loop systems. There is a lot of good reading about this in crystal radio web
              Message 6 of 23 , Jul 13, 2008
                At 03:52 PM 7/13/2008 +0000, you wrote:

                >Couple thingies to pass on ... a) I have found a practical limit to
                >"bigger is better" .... my 2 ft loop (15 turns of 20 ga (or is it 22
                >ga) solid copper is my best BCB loop 9 out of 10 times as opp to my
                >3.5 ft loop. Why? Combination of ease of use (rotation/placement) and
                >enough gain to grab the really weak ones (daytime signals). The big
                >loop with much bigger aperture and more gain seems to hit a theretical
                >point of "no more returns" at my QTH where residual noise becomes the
                >bigger issue. Have I "maxxed out" for my QTH? Perhaps. But maybe
                >not. I've yet to get my end-fed sloper up - perhaps that will surprise
                >me. But what really surprised me was this setup: I have a CCrane
                >Twin-Ferrite as well as the 2 ft loop and 3.5 ft loop. Each on it's
                >own gives me a significant gain and better s/n ratio on BCB than a
                >barefoot radio. I'd been using inductive coupling with the loops,
                >direct coupling with the T-F. One day I got a little crazy and
                >direct-connected the T-F, setting its ferrite head next to the 2 ft
                >loop which was sitting on a Lazy Susan. --> YES!!!!!! <--
                >The sum betters each individual contribution. I am now getting more
                >gain & improved s/n ratio using a combo of the two antennas. I mostly
                >spin the loop for direction but sometimes orienting the T-F head and
                >playing it's sweet/null points against the loops seems to give me more
                >null options. At any rate, this is a DX setup and not too gangly and
                >unwieldy. Perhaps someday I'll have a chance to put this setup
                >against a Quantum to see how it fairs for gain and null. The Quantum,
                >with it's Q multiplier, will always win in the Q department.
                >
                >b) I wonder about the performance difference between loops and long
                >wire and the 30:1 balun. I'm still attempting to become an antenna
                >expert (I'll let you know if/when I ever get there :) but from
                >reading, most end-fed long wires use a balun ranging from 4:1 to 9:1.
                >30:1 seems like a huge ratio. Can you elaborate on that? Is this a
                >store-bought or a home brew antenna? Did you wind the balun? Where
                >did you get plans?
                >
                >And I wonder about using the 30:1 balun with your loops. They both
                >have sense loops for direct-connect, correct? Wouldn't
                >direct-connecting yield more gain? Or is your rcvr loading down the
                >sense loop so you've connected a balun in between? I ask also because
                >I have a TG 34 and although I've never done a side-by-side with a BCB
                >loop, it never struck me as being as good a BCB antenna compared to
                >the multi-turn passive loops. Hmmm. Maybe I need to re-evaluate? Or
                >is the use of a 30:1 balun with the Terk & Tecsun hurting performance?
                >
                >Hope you can post more results. Good so far.
                >
                >Mark

                Hi Mark,

                The multi-inductor (loop) front end is superior to most single loop
                systems. There is a lot of good reading about this in 'crystal radio' web
                sites. I have experimented extensively with long wire antennas on MW (out
                at the farm) where there is no local RFI to deal with. I used direct
                connection to MW antenna terminals on such radios as the SRIII etc. and
                the normal 50 ohm input of radios such as the TS-50. There is some
                improvement using a RF transformer. However, My eyes were opened when I
                used the wire in conjunction with a HighQ loop. If you configure the loop
                as an 'antenna tuner' with a second wire as a counterpoise. It is possible
                to get the same performance with small (non-loop) High Q inductors in
                conjunction with the long wire.

                However, in an environment with RFI the performance of the long wire is
                diminished as the S/N ratio is not as good as with a tuned loop alone. to
                maximize MW performance from a long wire a High Q antenna tuner with
                counterpoise is required. I have not been able to achieve the same level
                with RF transformers ... eg wound on ferrite cores.

                Jim
              • aimo ruoho
                Oh, oh! I was just wondering by myself, that if people have their PC Monitor opened, when they are testing such small loops or other active or non-active
                Message 7 of 23 , Jul 13, 2008
                  Oh, oh!

                  I was just wondering by myself, that if people have their PC Monitor opened, when they are testing such small loops or other active or non-active antennas situated in their room, are they not able to think, that that may not be the most wise method to do things? At least it is not fair for those tests, not at all!

                  So, let us close all possible sources of  RFI (Radio Frequency Interference) in our home, when possible, if we want to receive just results, when doing such comparisons.
                  I just counted, how many pairs of outputs (electricity holes) I have in my radio room. 52!
                  How many computers and Monitors? 3. How many lamps? 9. How many Radio Receivers? 14. Plus 3 printers, 1 paper tearing machine, 3 pairs of active loudspeakers. 3 telephones.Then about antennas, how many? 9 coaxial cables coming from the upper and lower roofs. 32 different active and non-active loops and other types of antennas. (I am a very enthusiastic home-brewer of antennas and crystal receivers and other radio device.)

                  This just to tell the reader, that there really may be a lot of things in use or not  in one room to do the antenna-tests in a right or wrong manner.....
                  Best wishes!
                  Aimo

                  --- On Sun, 7/13/08, Fraser <fraser.castle@...> wrote:
                  From: Fraser <fraser.castle@...>
                  Subject: [loopantennas] Re: The Tale of three Chinese Loops - comparison and pictures
                  To: loopantennas@yahoogroups.com
                  Date: Sunday, July 13, 2008, 5:54 PM











                  --- In loopantennas@ yahoogroups. com, "gmcjetpilot" <gmcjetpilot@ ...>

                  wrote:

                  >

                  > Hi Mark:

                  >

                  > Roger that, the turns are close together (touching)

                  > and clearly spreading them out improves the low end.

                  >

                  > I just did my final test this time with a Ten Tec

                  > RX320D (PC radio).

                  >

                  > Using the S-meter was better. I ran all of them

                  > through a 30:1 balun.

                  >

                  > I also compared the three loops to may main

                  > antenna, a 60 foot random wire, approx 15-20 feet

                  > above ground, with 30:1 balun, grounded of course.

                  >

                  > The pecking order (MW band) is:

                  >

                  > Random wire

                  > TG34 amplified loop

                  > Terk Am Advantage

                  > Tecsun AN-200

                  >

                  >

                  > The random wire is better than the TG34 and both

                  > passove loops. The random wire random wire is

                  > significantly better than the two passive loops.

                  > The TG34 was also much better than the two passive

                  > loops.

                  >

                  > The two passive loops are close, but clearly of the

                  > two passive table top loops, the Terk has a bit more

                  > uhumph, based on my S-meter. Sound wise it was

                  > hard to tell, but on one station I though the Terk had

                  > lower noise or static.

                  >

                  > Surprisingly the random wire was more quiet, at

                  > least on the few stations I checked, but not always.

                  > Keeping in mind the random wire is outside and the two

                  > loops I had in a 2nd floor window sill, but near by CRT

                  > computer monitor, which no doubt added noise.

                  >

                  > Conclusion loops are awesome but just one tool in

                  > the antenna bag of tricks.

                  >

                  > My next antenna actually will be a 2' x 2' loop on

                  > an "X" frame. I just got the air capacitor in the

                  > mail. I expect to blow the 9" loops away. Bigger is

                  > better.

                  >

                  > One day I'll have room for a real long wire and/or a

                  > Wellbrook Loop on a rotor.

                  >

                  > Thanks for the input.

                  >

                  > George

                  >

                  >

                  >



                  Just read this and was interested to see the results. Only a couple

                  of comments on this test though....



                  1. I am not sure what was meant by the comment "Using the S-meter was

                  better. I ran all of them through a 30:1 balun."



                  The TG34 has an output impedance of approx 50 Ohms so why would you

                  put it into an impedance transformer ? (30:1 is one heck of an

                  impedance change)



                  2. Why was the S-Meter the measurement tool of choice ? An S-Meter

                  does not deliver a Signal to Noise ratio indication. It is well known

                  that Loops, active or passive, often produce less Signal strength but

                  that really is not the point. The signal to noise ratio is the key

                  performance indicator, provided the loop produces enough RF output to

                  overcome the noise floor of the receiver. Most modern HF receivers

                  are quiet enough and have enough AGC range to cope with the low RF

                  output of a decent loop. It is also worth noting that the Ten-Tec

                  is "hobbled" on frequencies below 2 MHz as a feature of it's design

                  so sensitivity is greatly reduced (I own an RX320 as well)



                  Jut some food for thought and don't forget that when comparing a long

                  wire aerial (antenna) with a loop, you are comparing E field and an H

                  field aerials ..... they behave totally differently when placed in

                  noisy (i.e domestic) RF environments ;-)



                  Best Wishes



                  Fraser





























                  [Non-text portions of this message have been removed]
                • aimo ruoho
                  What about if the compared antennas all have the same advantage of height? Should they not be tested equally? Only then we could see and hear, what they are
                  Message 8 of 23 , Jul 13, 2008
                    What about if the compared antennas all have the same advantage of height?
                    Should they not be tested equally?
                    Only then we could see and hear, what they are capable of!
                    Just my humble opinion.
                    It is said to be a fact, that on BCB the corresponding loop will give the best results, when it is near the earth level, right?
                    But if we test a random wire on the same level, what might be the results?
                    I have been testing the small Chinese loops from Degen on my roof with good results...

                    Most of the radio listeners are not able to put their antennas outside. So, we are very often just talking for the people, who have a lot of room outside and permission to erect a decent antenna, are we not? But they are a very small minority of the whole lot of people on this planet, right?
                    Best regards!

                    Aimo

                    --- On Sun, 7/13/08, gmcjetpilot <gmcjetpilot@...> wrote:
                    From: gmcjetpilot <gmcjetpilot@...>
                    Subject: [loopantennas] Re: The Tale of three Chinese Loops - comparison and pictures
                    To: loopantennas@yahoogroups.com
                    Date: Sunday, July 13, 2008, 1:10 AM











                    Hi Mark:



                    Roger that, the turns are close together (touching)

                    and clearly spreading them out improves the low end.



                    I just did my final test this time with a Ten Tec

                    RX320D (PC radio).



                    Using the S-meter was better. I ran all of them

                    through a 30:1 balun.



                    I also compared the three loops to may main

                    antenna, a 60 foot random wire, approx 15-20 feet

                    above ground, with 30:1 balun, grounded of course.



                    The pecking order (MW band) is:



                    Random wire

                    TG34 amplified loop

                    Terk Am Advantage

                    Tecsun AN-200



                    The random wire is better than the TG34 and both

                    passove loops. The random wire random wire is

                    significantly better than the two passive loops.

                    The TG34 was also much better than the two passive

                    loops.



                    The two passive loops are close, but clearly of the

                    two passive table top loops, the Terk has a bit more

                    uhumph, based on my S-meter. Sound wise it was

                    hard to tell, but on one station I though the Terk had

                    lower noise or static.



                    Surprisingly the random wire was more quiet, at

                    least on the few stations I checked, but not always.

                    Keeping in mind the random wire is outside and the two

                    loops I had in a 2nd floor window sill, but near by CRT

                    computer monitor, which no doubt added noise.



                    Conclusion loops are awesome but just one tool in

                    the antenna bag of tricks.



                    My next antenna actually will be a 2' x 2' loop on

                    an "X" frame. I just got the air capacitor in the

                    mail. I expect to blow the 9" loops away. Bigger is

                    better.



                    One day I'll have room for a real long wire and/or a

                    Wellbrook Loop on a rotor.



                    Thanks for the input.



                    George



                    >--- "airchecklover" <mdh@...> wrote:

                    >

                    > George;

                    >

                    > Nice job reporting test results. I need to

                    >embellish my statement about the Tecsun having

                    >many many turns (I was tired and did not say

                    >it correctly).

                    >

                    > I've only built larger loops, starting at 2 ft. They

                    >need 15 turns or so for a std. 15pf-360pf

                    >capacitor. 28 turns seems like alot but given it

                    >resonates, the number of turns is obviously

                    >matched with the correct value variable capacitor.

                    >A possible reason why the "Q" is low and tuning

                    >is wide is because the turns are very close

                    >together. It is a known fact inter-winding

                    >capacitance plays a role in loops and Q is reduced

                    >(ie, bandwidth is wider) with closer spacing of

                    >windings. As to why the Terk's bandwidth is

                    >tighter than the



                    >Tecsun, given the width of the loops appears to be

                    >about the same - I don't know without seeing the

                    >windings. One possibility is the Terk uses Litz

                    >wire which, by it's design, reduces inter-winding

                    >capacitance.

                    >

                    > Keep us posted if you take the Terk apart.

                    >

                    > Mark





























                    [Non-text portions of this message have been removed]
                  • gmcjetpilot@yahoo.com
                    MISTAKE...............good catch. Yea I meant 9:1 and I hand wound a toroid 31:11 turns (interlaced or overlapped). Usually the balun ratio is 30:10 so I had
                    Message 9 of 23 , Jul 14, 2008
                      MISTAKE...............good catch.

                      Yea I meant 9:1 and I hand wound a toroid 31:11 turns (interlaced or overlapped). Usually the balun ratio is 30:10 so I had 30 on my mind.

                      As far as the loops I was playing around more at night where some normally strong stations don't peg the needle because they drop power and go directional so I am on the back side of the main target.

                      The Terk loop did pull in more signal than the random wire/end fed.

                      Good catch 9:1 not 30................30 turns is what I had on my mind.



                      >b) I wonder about the performance difference between loops and long
                      >wire and the 30:1 balun. I'm still attempting to become an antenna
                      >expert (I'll let you know if/when I ever get there :) but from
                      >reading, most end-fed long wires use a balun ranging from 4:1 to 9:1.
                      >30:1 seems like a huge ratio. Can you elaborate on that? Is this a
                      >store-bought



                      [Non-text portions of this message have been removed]
                    • John Popelish
                      ... (interlaced or overlapped). Usually the balun ratio is 30:10 so I had 30 on my mind. (snip) I calculate an impedance ratio of 7.94:1 for a 31:11 turn
                      Message 10 of 23 , Jul 14, 2008
                        gmcjetpilot@... wrote:
                        > MISTAKE...............good catch.
                        >
                        > Yea I meant 9:1 and I hand wound a toroid 31:11 turns
                        (interlaced or overlapped). Usually the balun ratio is 30:10
                        so I had 30 on my mind.
                        (snip)

                        I calculate an impedance ratio of 7.94:1 for a 31:11 turn
                        balun. (31^2)/(11^2)=7.94

                        --
                        Regards,

                        John Popelish
                      • tenorman1952
                        ... (snip) ... You are not the first to report this. I have read this before, diminishing returns, etc. And just when I was going to start on some big loops.
                        Message 11 of 23 , Jul 14, 2008
                          --- In loopantennas@yahoogroups.com, "airchecklover" <mdh@...> wrote:

                          (snip)

                          > Couple thingies to pass on ... a) I have found a practical limit to
                          > "bigger is better" .... my 2 ft loop (15 turns of 20 ga (or is it 22
                          > ga) solid copper is my best BCB loop 9 out of 10 times as opp to my
                          > 3.5 ft loop. Why? Combination of ease of use (rotation/placement) and
                          > enough gain to grab the really weak ones (daytime signals). The big
                          > loop with much bigger aperture and more gain seems to hit a theretical
                          > point of "no more returns" at my QTH where residual noise becomes the
                          > bigger issue. Have I "maxxed out" for my QTH? Perhaps. But maybe
                          > not. I've yet to get my end-fed sloper up - perhaps that will surprise
                          > me.

                          You are not the first to report this. I have read this before,
                          diminishing returns, etc.

                          And just when I was going to start on some big loops. Food for
                          thought, for sure.

                          Paul C.
                          tenorman1952
                        • gmcjetpilot
                          Again 9:1 not 30:1 my bad...... Good point why use the balun with the loop. Don t know I ll try with out. I was thinking wire input = 300 ohm, like a TV. I as
                          Message 12 of 23 , Jul 14, 2008
                            Again 9:1 not 30:1 my bad......

                            Good point why use the balun with the loop. Don't know I'll try with
                            out. I was thinking wire input = 300 ohm, like a TV. I as also
                            thinking 66 feet of wire but forgot about the SENSE wire couple. I
                            really don't know what the impedance of the loop, but you say its
                            already 50 ohm? Cool. The AM radio does not say what input impedance
                            is? The FM is labeled 75 ohm.

                            S-meter? Yea why use it? Because it is the only thing I had to use
                            besides my ear. As I said my Mark IV calibrated ear says: Less
                            static, louder (aka stronger signal), better S/N etc...... Often its
                            too close to tell by ear.

                            As I was saying, on a strong station (turned down the juice at night
                            they don't peg the needle) the loop was better than the wire. However
                            any antenna will bring it in. With the S-meter I was able to make a
                            quantitative reading. However your comment about signal and S/N is
                            well taken and why my calibrates Mk IV-E ears are a good indicator.

                            The LOOP did better with the "stong" case in Par above, "soft pegged"
                            the needle (this is a RX320D, PC Radio so its all on the computer),
                            where the wire was floating around in the S-7's. Very small
                            difference really. The AN-200 was about the same as the wire and did
                            not soft peg the 10 on the **point-tee-thing (ha-ha). So I can only
                            gather the Terk AM Advantage has more Q than the AN-200. Again the
                            EAR said all same.

                            **(Note: S-meter on DX320D is software dependant - on the software I
                            was using, the signal strength meter scale was out of 10. Also most
                            RX320D software allows the user to "calabrate" or put a scale factor
                            in, so the actual number means nothing, relative to spacific "S-
                            meter" standards. However it is excellent for A-B comparisons.)


                            Radio RX320D: I know the radio is intentionally de-tuning for the MW
                            to avoid over-driving with strong AM BCB. There are two mods that
                            make it a MW and LF king monster. One, a very simple Cap bypass on
                            the antenna input, which makes it have significant gain to 100khz
                            (and below but most software controllers only allow tuning to
                            100Khz). The other mod is a different transformer, which, a little
                            more involved mod. The Euro crowd loves LF and VLF more than the US
                            radio market. They do these mods on this radio all the time. I know
                            there are LF stations in the EU. In the states with so many 50KW AM
                            stations they can overdrive the radio and cause problems on LF and SW
                            freqs. My radio is stock.

                            Good point on the E and M type antenna. I know bairly enough the
                            understand what you are saying. With my experience I understand what
                            you mean. Since a wrote as I said the LOOP showed better S/N than the
                            end fed, but you are right they are different and switching between
                            the two I am getting the hang of what they can do or not do.

                            Cheers George


                            2 MHz as a feature of it's design
                            > so sensitivity is greatly reduced (I own an RX320 as well)


                            --- In loopantennas@yahoogroups.com, "Fraser" <fraser.castle@...>
                            wrote:
                            >
                            > --- In loopantennas@yahoogroups.com, "gmcjetpilot" <gmcjetpilot@>
                            > wrote:
                            > >
                            > > Hi Mark:
                            > >
                            > > Roger that, the turns are close together (touching)
                            > > and clearly spreading them out improves the low end.
                            > >
                            > > I just did my final test this time with a Ten Tec
                            > > RX320D (PC radio).
                            > >
                            > > Using the S-meter was better. I ran all of them
                            > > through a 30:1 balun.
                            > >
                            > > I also compared the three loops to may main
                            > > antenna, a 60 foot random wire, approx 15-20 feet
                            > > above ground, with 30:1 balun, grounded of course.
                            > >
                            > > The pecking order (MW band) is:
                            > >
                            > > Random wire
                            > > TG34 amplified loop
                            > > Terk Am Advantage
                            > > Tecsun AN-200
                            > >
                            > >
                            > > The random wire is better than the TG34 and both
                            > > passove loops. The random wire random wire is
                            > > significantly better than the two passive loops.
                            > > The TG34 was also much better than the two passive
                            > > loops.
                            > >
                            > > The two passive loops are close, but clearly of the
                            > > two passive table top loops, the Terk has a bit more
                            > > uhumph, based on my S-meter. Sound wise it was
                            > > hard to tell, but on one station I though the Terk had
                            > > lower noise or static.
                            > >
                            > > Surprisingly the random wire was more quiet, at
                            > > least on the few stations I checked, but not always.
                            > > Keeping in mind the random wire is outside and the two
                            > > loops I had in a 2nd floor window sill, but near by CRT
                            > > computer monitor, which no doubt added noise.
                            > >
                            > > Conclusion loops are awesome but just one tool in
                            > > the antenna bag of tricks.
                            > >
                            > > My next antenna actually will be a 2' x 2' loop on
                            > > an "X" frame. I just got the air capacitor in the
                            > > mail. I expect to blow the 9" loops away. Bigger is
                            > > better.
                            > >
                            > > One day I'll have room for a real long wire and/or a
                            > > Wellbrook Loop on a rotor.
                            > >
                            > > Thanks for the input.
                            > >
                            > > George
                            > >
                            > >
                            > >
                            >
                            > Just read this and was interested to see the results. Only a couple
                            > of comments on this test though....
                            >
                            > 1. I am not sure what was meant by the comment "Using the S-meter
                            was
                            > better. I ran all of them through a 30:1 balun."
                            >
                            > The TG34 has an output impedance of approx 50 Ohms so why would you
                            > put it into an impedance transformer ? (30:1 is one heck of an
                            > impedance change)
                            >
                            >
                            > 2. Why was the S-Meter the measurement tool of choice ? An S-Meter
                            > does not deliver a Signal to Noise ratio indication. It is well
                            known
                            > that Loops, active or passive, often produce less Signal strength
                            but
                            > that really is not the point. The signal to noise ratio is the key
                            > performance indicator, provided the loop produces enough RF output
                            to
                            > overcome the noise floor of the receiver. Most modern HF receivers
                            > are quiet enough and have enough AGC range to cope with the low RF
                            > output of a decent loop. It is also worth noting that the Ten-Tec
                            > is "hobbled" on frequencies below 2 MHz as a feature of it's design
                            > so sensitivity is greatly reduced (I own an RX320 as well)
                            >
                            > Jut some food for thought and don't forget that when comparing a
                            long
                            > wire aerial (antenna) with a loop, you are comparing E field and an
                            H
                            > field aerials ..... they behave totally differently when placed in
                            > noisy (i.e domestic) RF environments ;-)
                            >
                            > Best Wishes
                            >
                            > Fraser
                            >
                          • gmcjetpilot
                            Yes, they all are the same height. The loops where all tested in a second floor, south facing, window, hanging or sitting on the sill. The window frame is
                            Message 13 of 23 , Jul 14, 2008
                              Yes, they all are the same height. The loops where all "tested" in a
                              second floor, south facing, window, hanging or sitting on the sill.

                              The window frame is all plastic and the window screen and screen
                              frame are also plastic. There may be some metal clips in there.

                              The Loops had a pretty good clear view of the south and to the E-W
                              (which seems to be the location of most stations due to larger radio
                              markets at the same latitude. Although there are many stations to the
                              south, requiring turning the loop 90 degrees. I suspect the North
                              stations are attenuated somewhat due to house structure, but that
                              radio waves can bounce around anyway.

                              The wire is coming out the same second floor window where the loops.
                              are. I tried to keep the loop away from the antenna wire and ground
                              wire, and doubt there was much if any interaction. The wire goes from
                              house to a tree. The feed line is coaxial through same window. GOOD
                              FEEDBACK!

                              As I was saying the Loops where near a CRT computer monitor. However
                              I unplugged and it did not seem to make a difference. Also per my
                              previous post there where some stations where clearly the LOOPS noise
                              rejection characteristic shinned more then the random wire, which may
                              have had stronger signal (s-meter or loudness) but also sometimes a
                              higher noise floor, aka S/N ratio. BE SURE LOOPS ROCK. Now to the
                              PLUS column of random wire, you don't NEED to point it or tune it
                              (although you can / should for max performance).

                              I think every loop should have an omni-directional antenna buddy on
                              an antenna switch for serious scanning. Loops are more work in some
                              ways than random listening. However for targeted freqs, loops rock
                              for size, cost and the performance possible. It is also ideal if you
                              can fit a random wire. I was challenged to get the random wire I have
                              in onto my small lot, and I still worry the HOA will send me a letter
                              telling me to take it down. (I just read the rules and they go into
                              satellite dish size, but states they require "architectural plans"
                              and approval of any out door antenna! May be I should submit it. You
                              can hardly see it. Its 22 awg stranded with white PTFE insulation. I
                              am thinking of putting a LOOP in the tree with a rotor and remote
                              tuning! The HOA does not allow antenna above the roof line. There is
                              the attic but I think out door and away for house (RFI) is goodness.

                              Cheers George



                              --- In loopantennas@yahoogroups.com, aimo ruoho <aimounto@...> wrote:
                              >
                              > What about if the compared antennas all have the same advantage of
                              height?
                              > Should they not be tested equally?
                              > Only then we could see and hear, what they are capable of!
                              > Just my humble opinion.
                              > It is said to be a fact, that on BCB the corresponding loop will
                              give the best results, when it is near the earth level, right?
                              > But if we test a random wire on the same level, what might be the
                              results?
                              > I have been testing the small Chinese loops from Degen on my roof
                              with good results...
                              >
                              > Most of the radio listeners are not able to put their antennas
                              outside. So, we are very often just talking for the people, who have
                              a lot of room outside and permission to erect a decent antenna, are
                              we not? But they are a very small minority of the whole lot of people
                              on this planet, right?
                              > Best regards!
                              >
                              > Aimo
                              >
                            • gmcjetpilot
                              I am not be wise (ha-ha) but I had the CRT off with the portable radio. I eliminated the the CRT by unplugging it. Also I can and do actually run my PC RADIO
                              Message 14 of 23 , Jul 14, 2008
                                I am not be wise (ha-ha) but I had the CRT off with the portable
                                radio. I eliminated the the CRT by unplugging it.

                                Also I can and do actually run my PC RADIO (Ten Tec RX320D) with out
                                CRT or computer running some times. I have a Palm Pilot with software
                                that allows me to tune the RX320D, and it even has a S-meter display.

                                The other method to run the RX320D with out computer is tune it with
                                the computer and turn the computer CRT and computer off (unplug). The
                                radio will continue to run at last freq and settings, but you don't
                                have any control of vol or have a S-meter. The RX320D is turned on
                                and off with a toggle switch on the black box itself.

                                The test I did with a AM/FM/CD/Tape Awia mini-stereo (with no
                                internal AM antenna) was tested was down stairs, away from the CRT.
                                There is a LCD TV, which does give off noise if real close.
                                Fortunately is out of line from most of the stations. I only compared
                                the Terk and Tecsun on the Stereo. All other comparisons with the
                                portable and RX320D was done upstairs. I wrote about the 1' x 1'
                                pizza box non-tuned loop I made for this Aiwa stereo. It does pretty
                                good on the two powerful stations to the east (and yes the wall its
                                on is E-W), and hard pressed to tell the diff on those two stations.
                                However after trying all the AM stations I should be able to get
                                (according to the Radio Locate web site), I have to say the Awia is
                                not a AM radio DX machine. Also being down stairs, not by a window
                                and with a few internal walls in the way, reduces LOOP performance.

                                RFI Expert? (well at least for my installation)

                                A really good point about noise but let me say I have a lot
                                experience with this. When I first got the RX320D I had a heck of a
                                time with RFI. The RX320D is tied to a computer, so its a necessary
                                evil. After much time and effort I found where all the noise was
                                coming from and what worked antenna wise. I went around with a
                                portable SW radio looking for local noise. Yes the CRT, Computer,
                                Mouse(wireless) and even key board (wired) give off some near RFI,
                                but you almost have to touch it with the whip antenna. The WiFi at
                                2.4Ghz was not a factor.

                                The real culprit was the scanner/printer combo, even in idle, it was
                                a radio station from 17-23Mhz. The mouse obliterates the 11 meter
                                27Mhz band, but only when moving the mouse. The CRT was not bad
                                unless you're almost touching it. The test "WINDOW" is about 6 feet
                                away, not perfect but acceptable. I found little ore no diff with CRT
                                on or off, but that was because the loops where not pointed right at
                                it.

                                Again I did find stations and senerios where the LOOP had clearly
                                better S/N ratio than the random wire.

                                When I first got my RX320D it was terrible with an indoor amplified
                                mono poll antenna, S/N ratio wise. It was not till I strung the
                                random wire outside, with a coaxial feed, ground with a 9:1 balun did
                                I get it the RX320D to sing. Since I have DX'ed New Zealand and
                                Kuwait in DRM! That blows me away. The antenna is not great just
                                workable, but does indicate what a good radio the RX320D is.

                                My random wire needs help still, in that it comes up to the window
                                before transition to coaxial, where the ground wire taps in as well.
                                I need to move the wire antenna end feed termination on a non-
                                conductive tether, away from the house, verse right at the window. I
                                have been so happy and impressed with the performance, so I have not
                                bothered to improve the wire antenna.

                                The CRT, if it had a large affect on the loops, it would affect the
                                wire antenna somewhat as well, since all have some part approx the
                                same distance from the CRT.

                                THANKS FOR THE GREAT COMMENTS GUYS (gals?). George


                                --- In loopantennas@yahoogroups.com, aimo ruoho <aimounto@...> wrote:
                                >
                                > Oh, oh!
                                >
                                > I was just wondering by myself, that if people have their PC
                                Monitor opened, when they are testing such small loops or other
                                active or non-active antennas situated in their room, are they not
                                able to think, that that may not be the most wise method to do
                                things? At least it is not fair for those tests, not at all!
                                >
                                > So, let us close all possible sources of  RFI (Radio Frequency
                                Interference) in our home, when possible, if we want to receive just
                                results, when doing such comparisons.
                                > I just counted, how many pairs of outputs (electricity holes) I
                                have in my radio room. 52!
                                > How many computers and Monitors? 3. How many lamps? 9. How many
                                Radio Receivers? 14. Plus 3 printers, 1 paper tearing machine, 3
                                pairs of active loudspeakers. 3 telephones.Then about antennas, how
                                many? 9 coaxial cables coming from the upper and lower roofs. 32
                                different active and non-active loops and other types of antennas. (I
                                am a very enthusiastic home-brewer of antennas and crystal receivers
                                and other radio device.)
                                >
                                > This just to tell the reader, that there really may be a lot of
                                things in use or not  in one room to do the antenna-tests in a right
                                or wrong manner.....
                                > Best wishes!
                                > Aimo
                                >
                                > --- On Sun, 7/13/08, Fraser <fraser.castle@...> wrote:
                                > From: Fraser <fraser.castle@...>
                                > Subject: [loopantennas] Re: The Tale of three Chinese Loops -
                                comparison and pictures
                                > To: loopantennas@yahoogroups.com
                                > Date: Sunday, July 13, 2008, 5:54 PM
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                > --- In loopantennas@ yahoogroups. com, "gmcjetpilot"
                                <gmcjetpilot@ ...>
                                >
                                > wrote:
                                >
                                > >
                                >
                                > > Hi Mark:
                                >
                                > >
                                >
                                > > Roger that, the turns are close together (touching)
                                >
                                > > and clearly spreading them out improves the low end.
                                >
                                > >
                                >
                                > > I just did my final test this time with a Ten Tec
                                >
                                > > RX320D (PC radio).
                                >
                                > >
                                >
                                > > Using the S-meter was better. I ran all of them
                                >
                                > > through a 30:1 balun.
                                >
                                > >
                                >
                                > > I also compared the three loops to may main
                                >
                                > > antenna, a 60 foot random wire, approx 15-20 feet
                                >
                                > > above ground, with 30:1 balun, grounded of course.
                                >
                                > >
                                >
                                > > The pecking order (MW band) is:
                                >
                                > >
                                >
                                > > Random wire
                                >
                                > > TG34 amplified loop
                                >
                                > > Terk Am Advantage
                                >
                                > > Tecsun AN-200
                                >
                                > >
                                >
                                > >
                                >
                                > > The random wire is better than the TG34 and both
                                >
                                > > passove loops. The random wire random wire is
                                >
                                > > significantly better than the two passive loops.
                                >
                                > > The TG34 was also much better than the two passive
                                >
                                > > loops.
                                >
                                > >
                                >
                                > > The two passive loops are close, but clearly of the
                                >
                                > > two passive table top loops, the Terk has a bit more
                                >
                                > > uhumph, based on my S-meter. Sound wise it was
                                >
                                > > hard to tell, but on one station I though the Terk had
                                >
                                > > lower noise or static.
                                >
                                > >
                                >
                                > > Surprisingly the random wire was more quiet, at
                                >
                                > > least on the few stations I checked, but not always.
                                >
                                > > Keeping in mind the random wire is outside and the two
                                >
                                > > loops I had in a 2nd floor window sill, but near by CRT
                                >
                                > > computer monitor, which no doubt added noise.
                                >
                                > >
                                >
                                > > Conclusion loops are awesome but just one tool in
                                >
                                > > the antenna bag of tricks.
                                >
                                > >
                                >
                                > > My next antenna actually will be a 2' x 2' loop on
                                >
                                > > an "X" frame. I just got the air capacitor in the
                                >
                                > > mail. I expect to blow the 9" loops away. Bigger is
                                >
                                > > better.
                                >
                                > >
                                >
                                > > One day I'll have room for a real long wire and/or a
                                >
                                > > Wellbrook Loop on a rotor.
                                >
                                > >
                                >
                                > > Thanks for the input.
                                >
                                > >
                                >
                                > > George
                                >
                                > >
                                >
                                > >
                                >
                                > >
                                >
                                >
                                >
                                > Just read this and was interested to see the results. Only a couple
                                >
                                > of comments on this test though....
                                >
                                >
                                >
                                > 1. I am not sure what was meant by the comment "Using the S-meter
                                was
                                >
                                > better. I ran all of them through a 30:1 balun."
                                >
                                >
                                >
                                > The TG34 has an output impedance of approx 50 Ohms so why would you
                                >
                                > put it into an impedance transformer ? (30:1 is one heck of an
                                >
                                > impedance change)
                                >
                                >
                                >
                                > 2. Why was the S-Meter the measurement tool of choice ? An S-Meter
                                >
                                > does not deliver a Signal to Noise ratio indication. It is well
                                known
                                >
                                > that Loops, active or passive, often produce less Signal strength
                                but
                                >
                                > that really is not the point. The signal to noise ratio is the key
                                >
                                > performance indicator, provided the loop produces enough RF output
                                to
                                >
                                > overcome the noise floor of the receiver. Most modern HF receivers
                                >
                                > are quiet enough and have enough AGC range to cope with the low RF
                                >
                                > output of a decent loop. It is also worth noting that the Ten-Tec
                                >
                                > is "hobbled" on frequencies below 2 MHz as a feature of it's design
                                >
                                > so sensitivity is greatly reduced (I own an RX320 as well)
                                >
                                >
                                >
                                > Jut some food for thought and don't forget that when comparing a
                                long
                                >
                                > wire aerial (antenna) with a loop, you are comparing E field and an
                                H
                                >
                                > field aerials ..... they behave totally differently when placed in
                                >
                                > noisy (i.e domestic) RF environments ;-)
                                >
                                >
                                >
                                > Best Wishes
                                >
                                >
                                >
                                > Fraser
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                >
                                > [Non-text portions of this message have been removed]
                                >
                              • gmcjetpilot
                                Ha-ha, OK I love a stickler for details. Good catch. Now that you brought it up, can you enlighten me how the math is derived. I just copied a design off the
                                Message 15 of 23 , Jul 15, 2008
                                  Ha-ha, OK I love a stickler for details. Good catch. Now that you
                                  brought it up, can you enlighten me how the math is derived.

                                  I just copied a design off the web that was measured or reported to
                                  be 9:1. 30:10 is more traditional but recall the extra turn was to
                                  compensate for something, which I don't recall. I believe what he did
                                  was wind it, test it on the radio and than added turns. I suspect my
                                  shorter random wire is less than 450 ohms. No random wire is not
                                  exactly 450 ohms. I read 300-600 ohms is typical, so 450 ohm is right
                                  in the mid range.

                                  HOW DO YOU MEASURE antenna or balun impedance? Does it take lab
                                  equipment? Is it possible to measure it exactly? I suppose it's
                                  possible, but how it reacts under a particular RF is another issue,
                                  right? (0r is it easy to measure?)

                                  Is the ratio of turns squared (by the way math wise [31/11]^2 is the
                                  same as 31^2/11^2) accurate?

                                  I know the torrid size is not critical but the material is for freq
                                  response. The way you wrap the Prim/Sec also affects it?

                                  Thanks George



                                  --- In loopantennas@yahoogroups.com, John Popelish <jpopelish@...>
                                  wrote:
                                  >
                                  > gmcjetpilot@... wrote:
                                  > > MISTAKE...............good catch.
                                  > >
                                  > > Yea I meant 9:1 and I hand wound a toroid 31:11 turns
                                  > (interlaced or overlapped). Usually the balun ratio is 30:10
                                  > so I had 30 on my mind.
                                  > (snip)
                                  >
                                  > I calculate an impedance ratio of 7.94:1 for a 31:11 turn
                                  > balun. (31^2)/(11^2)=7.94
                                  >
                                  > --
                                  > Regards,
                                  >
                                  > John Popelish
                                  >
                                • John Popelish
                                  ... Of course, it is an approximation of reality based on the ideal transformer assumptions of perfect magnetic coupling of the turns and an infinite parallel
                                  Message 16 of 23 , Jul 15, 2008
                                    gmcjetpilot wrote:
                                    > Ha-ha, OK I love a stickler for details. Good catch. Now that you
                                    > brought it up, can you enlighten me how the math is derived.

                                    Of course, it is an approximation of reality based on the
                                    ideal transformer assumptions of perfect magnetic coupling
                                    of the turns and an infinite parallel inductance. but, in
                                    reality, if the balun is well arranged on core material that
                                    has good permeability and low losses in the frequency band
                                    of interest, these can be pretty good approximations. Well
                                    coupled turns have an inductance proportional to the turns
                                    squared. Well coupled turns also share the same volts per
                                    turn and two different well coupled windings share the same
                                    ampere turns total. Those are the effects that cause the
                                    impedance reflected through an ideal balun (or transformer)
                                    to have a turns squared ratio. Less than perfectly coupled
                                    turns have a lower power impedance ratio.

                                    > I just copied a design off the web that was measured or reported to
                                    > be 9:1. 30:10 is more traditional but recall the extra turn was to
                                    > compensate for something, which I don't recall.

                                    Again, the ratio should always be labeled as an impedance
                                    ratio (somewhat hypothetical in the absence of accurate
                                    measurement) or a turns ratio (pretty accurate if you can
                                    count the turns).

                                    > I believe what he did
                                    > was wind it, test it on the radio and than added turns. I suspect my
                                    > shorter random wire is less than 450 ohms. No random wire is not
                                    > exactly 450 ohms. I read 300-600 ohms is typical, so 450 ohm is right
                                    > in the mid range.
                                    >
                                    > HOW DO YOU MEASURE antenna or balun impedance? Does it take lab
                                    > equipment? Is it possible to measure it exactly? I suppose it's
                                    > possible, but how it reacts under a particular RF is another issue,
                                    > right? (0r is it easy to measure?)

                                    If you have a setup that can excite the device while it is
                                    loaded with a known load (a low inductance resistor, for
                                    instance), while measuring the voltage applied and the
                                    current through its input, you can calculate the impedance.
                                    I think the lab equipment that does this is a vector
                                    impedance meter. Of course, this measurement varies with
                                    frequency, so a bunch of points over a range of frequency is
                                    needed to really quantify its performance for anything other
                                    than single frequency operation. It is also useful to
                                    measure its impedance with the other end both open and short
                                    circuited.

                                    > Is the ratio of turns squared (by the way math wise [31/11]^2 is the
                                    > same as 31^2/11^2) accurate?

                                    Only if the turns are well coupled, magnetically.

                                    > I know the torrid size is not critical but the material is for freq
                                    > response.

                                    You generally want to use the highest permeability material
                                    that does not have losses so high that they look like a
                                    significant parallel load across the balun. Higher
                                    permeability implies higher coupling, and higher inductance
                                    in parallel with the transformed impedance, all other things
                                    being equal.

                                    > The way you wrap the Prim/Sec also affects it?

                                    Yes, you have to be concerned with the stray capacitance
                                    both across each winding, and between the turns of different
                                    windings. details count, especially if you are pushing the
                                    high frequency end of the balun's capability. Best winding
                                    form at the high frequency end makes use of transmission
                                    line effects (electric and magnetic field waves along the
                                    wire length) in addition to just bulk magnetic field
                                    coupling. But at the low frequency end core permeability
                                    and turns squared dominate all other effects.

                                    So, a good balun design begins with a set or requirements
                                    for frequency band (both ends set limits on choices) and the
                                    impedances needed on both sides.

                                    --
                                    Regards,

                                    John Popelish
                                  • richard woltmann
                                    Lightning burnt a TV antenna,so need a loop suggest one to use with 320 tentac,please Richard Woltmann ... From: Fraser Subject:
                                    Message 17 of 23 , Jul 19, 2008
                                      Lightning burnt a TV antenna,so need a loop suggest one to use with 320 tentac,please

                                      Richard Woltmann

                                      --- On Sun, 7/13/08, Fraser <fraser.castle@...> wrote:

                                      From: Fraser <fraser.castle@...>
                                      Subject: [loopantennas] Re: The Tale of three Chinese Loops - comparison and pictures
                                      To: loopantennas@yahoogroups.com
                                      Date: Sunday, July 13, 2008, 11:54 AM

                                      --- In loopantennas@yahoogroups.com, "gmcjetpilot"
                                      <gmcjetpilot@...>
                                      wrote:
                                      >
                                      > Hi Mark:
                                      >
                                      > Roger that, the turns are close together (touching)
                                      > and clearly spreading them out improves the low end.
                                      >
                                      > I just did my final test this time with a Ten Tec
                                      > RX320D (PC radio).
                                      >
                                      > Using the S-meter was better. I ran all of them
                                      > through a 30:1 balun.
                                      >
                                      > I also compared the three loops to may main
                                      > antenna, a 60 foot random wire, approx 15-20 feet
                                      > above ground, with 30:1 balun, grounded of course.
                                      >
                                      > The pecking order (MW band) is:
                                      >
                                      > Random wire
                                      > TG34 amplified loop
                                      > Terk Am Advantage
                                      > Tecsun AN-200
                                      >
                                      >
                                      > The random wire is better than the TG34 and both
                                      > passove loops. The random wire random wire is
                                      > significantly better than the two passive loops.
                                      > The TG34 was also much better than the two passive
                                      > loops.
                                      >
                                      > The two passive loops are close, but clearly of the
                                      > two passive table top loops, the Terk has a bit more
                                      > uhumph, based on my S-meter. Sound wise it was
                                      > hard to tell, but on one station I though the Terk had
                                      > lower noise or static.
                                      >
                                      > Surprisingly the random wire was more quiet, at
                                      > least on the few stations I checked, but not always.
                                      > Keeping in mind the random wire is outside and the two
                                      > loops I had in a 2nd floor window sill, but near by CRT
                                      > computer monitor, which no doubt added noise.
                                      >
                                      > Conclusion loops are awesome but just one tool in
                                      > the antenna bag of tricks.
                                      >
                                      > My next antenna actually will be a 2' x 2' loop on
                                      > an "X" frame. I just got the air capacitor in the
                                      > mail. I expect to blow the 9" loops away. Bigger is
                                      > better.
                                      >
                                      > One day I'll have room for a real long wire and/or a
                                      > Wellbrook Loop on a rotor.
                                      >
                                      > Thanks for the input.
                                      >
                                      > George
                                      >
                                      >
                                      >

                                      Just read this and was interested to see the results. Only a couple
                                      of comments on this test though....

                                      1. I am not sure what was meant by the comment "Using the S-meter was
                                      better. I ran all of them through a 30:1 balun."

                                      The TG34 has an output impedance of approx 50 Ohms so why would you
                                      put it into an impedance transformer ? (30:1 is one heck of an
                                      impedance change)


                                      2. Why was the S-Meter the measurement tool of choice ? An S-Meter
                                      does not deliver a Signal to Noise ratio indication. It is well known
                                      that Loops, active or passive, often produce less Signal strength but
                                      that really is not the point. The signal to noise ratio is the key
                                      performance indicator, provided the loop produces enough RF output to
                                      overcome the noise floor of the receiver. Most modern HF receivers
                                      are quiet enough and have enough AGC range to cope with the low RF
                                      output of a decent loop. It is also worth noting that the Ten-Tec
                                      is "hobbled" on frequencies below 2 MHz as a feature of it's
                                      design
                                      so sensitivity is greatly reduced (I own an RX320 as well)

                                      Jut some food for thought and don't forget that when comparing a long
                                      wire aerial (antenna) with a loop, you are comparing E field and an H
                                      field aerials ..... they behave totally differently when placed in
                                      noisy (i.e domestic) RF environments ;-)

                                      Best Wishes

                                      Fraser


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                                      [Non-text portions of this message have been removed]
                                    • gmcjetpilot
                                      *Please do not cut and past whole post * Hi Richard: I don t follow your question. Also PLEASE no need to cut and past whole post, especially my overly long
                                      Message 18 of 23 , Jul 20, 2008
                                        *Please do not cut and past whole post *

                                        Hi Richard:

                                        I don't follow your question. Also PLEASE no need to cut and past
                                        whole post, especially my overly long ones, :)

                                        You say TenTec 320? I use a nice random wire about 15' off the ground
                                        about 50 feet long through a 9:1 balun. Works great.

                                        I like the Wellbrook loops but they cost a lot.
                                        http://www.wellbrook.uk.com/ALA1530.html

                                        What band are you targeting? If you want from 100-30,000 than
                                        something like the wellbrook. So you want to make one?

                                        More info needed.

                                        What does TV antenna have to do with it?

                                        Cheers
                                        George

                                        * Please do not cut and past whole whole post *




                                        --- In loopantennas@yahoogroups.com, richard woltmann <rwoltmann@...>
                                        wrote:
                                        >
                                        > Lightning burnt a TV antenna,so need a loop suggest one to use with
                                        320 tentac,please
                                        >
                                        > Richard Woltmann
                                        >
                                      Your message has been successfully submitted and would be delivered to recipients shortly.