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Re: Help

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  • mhatlau
    To my mind, the Select-A-Tenna is a bit overpriced. It contains a twelve inch diameter coil of wire, connected in parallel with a 365pF air-variable
    Message 1 of 20 , Dec 1, 2007
      To my mind, the Select-A-Tenna is a bit overpriced. It contains a
      twelve inch diameter coil of wire, connected in parallel with a 365pF
      air-variable capacitor, all in a plastic coil-form case.

      As for performance, it has helped nearly every receiver with a ferite
      antenna I have used mine with, nearly always tremendously. I use it a
      lot with the ICF-2010. The two exceptions are (1) R-392. The R-392
      does not have a ferite loop, so I have to use the built-in pick-up
      coil, which is an isolated turn on the same plane as the primary coil
      in the Select-A-Tenna. Unfortunately, this is too closely coupled
      with the Select-A-Tenna coil, so the low impedance of the R-392
      antenna input shorts out the tank circuit in the Select-A-Tenna,
      making it useless. (2) My GE Superadio III. The twelve inch coil in
      the Select-A-Tenna has about the same virtual height and aperture as
      the seven and a half inch ferite rod in the Superadio. So at best, it
      only adds 3 dB to the signal, barely detectable. On the other hand,
      by tuning the Select-A-Tenna slightly above or below the desired
      signal, you can change the phase of the re-radiated signal at the
      desired frequency. This phase shifted re-radiated signal is then
      coupled into the Superadio ferite loop and adds with the existing
      original signal. The result is much deeper nulls than can be achieved
      with the Superadio antenna alone, making it quite useful even with the
      Superadio, abet not as intended. So my advice is that if you think
      the extra cost($59.95 + S&H) for a nice out of the box package is
      worth the $20-40 you would save by building it yourself, then go for
      it. It definitely is not snake oil.

      On the other hand, if you have the tools and skill for a bit of basic
      woodworking, you can make a much more sensitive loop for about $20-40,
      depending on how fancy you want to make it (for example, turned
      spreaders of Cherry, and a ball-bearing base).

      --- In loopantennas@yahoogroups.com, "Dennis Gibson" <wb6tnb@...> wrote:
      >
      > I have used a Select-a-Tenna for 25 years and it still works very
      > well. I have the least expensive model (541). I've used it with many
      > radios and it always makes a huge increase in signal strength;
      > especially with weak signals. I highly recommend it.
      >
      > http://www.selectatenna.com
      >
      > --- In loopantennas@yahoogroups.com, "tommika1" <tommika@> wrote:
      > >
      > > Newbie here. I'm at the edge of reception on AM 1330 near Salem,SC
      and
      > > would appreciate knowing what to buy for house radio. The signal
      fades
      > > rapidly in the later afternoon and is decent at mid-day. I read
      about a
      > > double ferrite core type (I think) but it was about $100 plus extra
      > > cost for cable to run outside. Is there something out there that
      works
      > > without so much expense. Thanks for any help you can offer.
      >
    • Jim Dunstan
      ... You are correct .... I have a home made Select-A-Tenna that costs $0.00. It consists of approx 60 ft of insulated hookup wire, a couple of small pieces
      Message 2 of 20 , Dec 1, 2007
        At 01:07 PM 12/1/2007 +0000, you wrote:

        >To my mind, the Select-A-Tenna is a bit overpriced. It contains a
        >twelve inch diameter coil of wire, connected in parallel with a 365pF
        >air-variable capacitor, all in a plastic coil-form case.


        You are correct .... I have a home made Select-A-Tenna that costs
        $0.00. It consists of approx 60' ft of insulated hookup wire, a couple of
        small pieces of plywood, 12" of small wood dowel, and a 365 pfd capacitor
        from an old junked radio. I use the Tivioli radio because it is small
        4x4x6 inch ... and has a ferrite antenna that couples to the 1'x1' loop and
        has great audio. The loop and radio sit on the same wood base .. about
        8"x8" (with cloth glued to the bottom). I rotate them together for best
        reception and simply tune the 365 pfd capacitor. It is relatively small
        and outperforms such AM radios as the Superadio III.

        Jim
      • Richards
        Hey Mr. mhatlau -- Why don t you make your own separate pickup loop and just tape it to the outside of the Select-a-Tenna plastic case, and wire it to the
        Message 3 of 20 , Dec 2, 2007
          Hey Mr. mhatlau -- Why don't you make your own separate
          pickup loop and just tape it to the outside of the Select-a-Tenna
          plastic case, and wire it to the radio, or an inductive coupler?

          That would, I think, sufficiently de-couple the pickup loop from
          the coil inside... n'est ce pas?

          Happy Trails. /// Richards - KD8JHR ///
          ===========================================

          mhatlau wrote:
          I have to use the built-in pick-up
          > coil, which is an isolated turn on the same plane as the primary coil
          > in the Select-A-Tenna. Unfortunately, this is too closely coupled
          > with the Select-A-Tenna coil, so the low impedance of the R-392
          > antenna input shorts out the tank circuit in the Select-A-Tenna,
          > making it useless.

          ================================================
        • mhatlau
          Good Guess. And that is exactly what I tried. Loaded down the R-392 input tuned circuits, so I went to Plan 9 ;) Opened up a $.50 Yard-Sale Special
          Message 4 of 20 , Dec 2, 2007
            Good Guess. And that is exactly what I tried. Loaded down the R-392
            input tuned circuits, so I went to Plan 9 ;) Opened up a $.50
            Yard-Sale Special transistor radio and pulled the one inch ferite
            antenna out of it. Then ripped out the useless miniature audio jack
            and hooked a BNC connector up to the ferite loop. Cut a hole in the
            back of the Select-A-Tenna so I could put it inside, about three
            inches from the loop and at right angles to it with Epoxy. The nice
            thing about it is that now the pick-up loop has a high enough
            impedance that it does not load down the R-392, yet is decoupled
            enough I get really sharp tuning.

            P.S. For those not in the Computer Business, 'Plan 9' is a synonym
            for either a REALLY bad hack, or a REALLY good hack. For example, the
            first multi-user operating system capable of being fitted into a cheap
            personal computer was OS-9, renamed from Plan-9. The writers of WIN
            98 and Apple Mac borrowed heavily from it. And Radio Shack used it
            for their Color Computer.

            The expression hearkens back to Ed Woods Classic 'Plan 9 from Outer
            Space', a movie so bad, it was great! To quote some reviews; "This is
            one of the best of the worst films of all time. Poor production
            values, terrible acting, worse directing, and dialog that has to be
            heard to be believed, combine to create a cinematic gem. This is a
            movie that has absolutely no redeeming qualities. "Plan 9" is so full
            of great badness that to detail all the goofs, flubs, and cheesiness
            would require remaking the entire movie. The cemetery is a
            weed-infested lot; an airline cockpit set is a shower curtain, some
            plywood and a couple chairs; a cop scratches his head with the
            business end of a gun barrel; the outside of the space ship has a
            ladder that goes nowhere; the spaceship is a hubcap suspended on a
            string...which catches fire at one point; the plan itself, that is,
            plan number 9, makes no sense at all. And on and on and on..."


            --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
            >
            > Hey Mr. mhatlau -- Why don't you make your own separate
            > pickup loop and just tape it to the outside of the Select-a-Tenna
            > plastic case, and wire it to the radio, or an inductive coupler?
            >
            > That would, I think, sufficiently de-couple the pickup loop from
            > the coil inside... n'est ce pas?
            >
            > Happy Trails. /// Richards - KD8JHR ///
            > ===========================================
            >
            > mhatlau wrote:
            > I have to use the built-in pick-up
            > > coil, which is an isolated turn on the same plane as the primary coil
            > > in the Select-A-Tenna. Unfortunately, this is too closely coupled
            > > with the Select-A-Tenna coil, so the low impedance of the R-392
            > > antenna input shorts out the tank circuit in the Select-A-Tenna,
            > > making it useless.
            >
            > ================================================
            >
          • Richards
            Great story --- I will have to rent a copy of that flick. I like comedy. You put the ferrite loop antenna from the little radio into the S-a-Tenna? Or did
            Message 5 of 20 , Dec 2, 2007
              Great story --- I will have to rent a copy of that flick. I like comedy.

              You put the ferrite loop antenna from the little radio into the
              S-a-Tenna? Or did you use that as the coupler for outside?

              Sorry if I am a little dense and did not quite get the picture...
              I am getting the notion you put the ferrite bar inside as the
              pickup loop and then hard wired the thing to the antenna jack
              on the receiver. Or is it the other way around...?

              /////////////// Richards ///////////////
              ==============================================

              mhatlau wrote:
              and pulled the one inch ferite
              > antenna out of it. Then ripped out the useless miniature audio jack
              > and hooked a BNC connector up to the ferite loop. Cut a hole in the
              > back of the Select-A-Tenna so I could put it inside, about three
              > inches from the loop and at right angles to it with Epoxy.

              =============================================
            • mhatlau
              I have the one with the external jack on it. I opened it up to examine it, by cutting a hole in the back of the case. And found that the Select-A-Tenna
              Message 6 of 20 , Dec 3, 2007
                I have the one with the external jack on it. I opened it up to
                examine it, by cutting a hole in the back of the case. And found that
                the Select-A-Tenna consists of a round case with about #28 magnet wire
                wound around the circumference, the ends soldered to a single gang
                365pf capacitor mounted in the middle of the front panel. No trimming
                is provided. The External jack model varies from the origional by the
                addition of an extra turn wound around the circumfrence and connected
                to a cheap 1/8" (3.5mm) phone jack. This results in very tight
                coupling, which if hooked to a low-impedance load, will 'short out'
                the floating tank circuit Q.

                What I did was to first try a looser coupling by taping a single turn
                to the back of the case, and it worked a bit better for all the
                receivers except the R-392. I then modeled the Select-a-tenna using
                RJELOOP3. It gives me a 100-400 ohm impedance for the pick-up loop.
                To get more impedance for the pick-up loop, I decided to try a ferite
                loop pick-up instead. I wired the promary coil to a BNC connector and
                connected the BNC connector to my R-392. The result was much better.
                I then moved the ferite loop around inside, looking for a sweet-spot,
                which was near the center, about three inches from the edge. Finally,
                I mounted the BNC connector to the front panel where the phone jack
                used to be, and epoxied the ferite core to the inside of the back
                panel, orentated with the core going back to front. Finally, a few
                pieces of Duck-Tape to cover the hole, and glued the Select-A-Tenna
                base to a plastic condement turntable to allow me to turn the loop.

                --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
                >
                > Great story --- I will have to rent a copy of that flick. I like
                comedy.
                >
                > You put the ferrite loop antenna from the little radio into the
                > S-a-Tenna? Or did you use that as the coupler for outside?
                >
                > Sorry if I am a little dense and did not quite get the picture...
                > I am getting the notion you put the ferrite bar inside as the
                > pickup loop and then hard wired the thing to the antenna jack
                > on the receiver. Or is it the other way around...?
                >
                > /////////////// Richards ///////////////
                > ==============================================
                >
                > mhatlau wrote:
                > and pulled the one inch ferite
                > > antenna out of it. Then ripped out the useless miniature audio jack
                > > and hooked a BNC connector up to the ferite loop. Cut a hole in the
                > > back of the Select-A-Tenna so I could put it inside, about three
                > > inches from the loop and at right angles to it with Epoxy.
                >
                > =============================================
                >
              • Richards
                thank you very much for that very detailed and clear explanation. I get it really well now. This sounds similar to something Bob Bettes did with his Terk
                Message 7 of 20 , Dec 3, 2007
                  thank you very much for that very detailed and clear explanation.
                  I get it really well now. This sounds similar to something Bob Bettes
                  did with his Terk Advantage loop antenna. See details here:

                  http://www.geocities.com/amdxlog/terk.html

                  Happy Trails and 73. ///// Richards - KD8JHR /////
                  ======================================================
                  mhatlau wrote:
                  > I have the one with the external jack on it. I opened it up to
                  > examine it, by cutting a hole in the back of the case. And found that
                  > the Select-A-Tenna consists of a round case with about #28 magnet wire
                  > wound around the circumference, the ends soldered to a single gang
                  > 365pf capacitor mounted in the middle of the front panel. No trimming
                  > is provided. The External jack model varies from the origional by the
                  > addition of an extra turn wound around the circumfrence and connected
                  > to a cheap 1/8" (3.5mm) phone jack. This results in very tight
                  > coupling, which if hooked to a low-impedance load, will 'short out'
                  > the floating tank circuit Q.
                  >
                  > What I did was to first try a looser coupling by taping a single turn
                  > to the back of the case, and it worked a bit better for all the
                  > receivers except the R-392. I then modeled the Select-a-tenna using
                  > RJELOOP3. It gives me a 100-400 ohm impedance for the pick-up loop.
                  > To get more impedance for the pick-up loop, I decided to try a ferite
                  > loop pick-up instead. I wired the promary coil to a BNC connector and
                  > connected the BNC connector to my R-392. The result was much better.
                  > I then moved the ferite loop around inside, looking for a sweet-spot,
                  > which was near the center, about three inches from the edge. Finally,
                  > I mounted the BNC connector to the front panel where the phone jack
                  > used to be, and epoxied the ferite core to the inside of the back
                  > panel, orentated with the core going back to front. Finally, a few
                  > pieces of Duck-Tape to cover the hole, and glued the Select-A-Tenna
                  > base to a plastic condement turntable to allow me to turn the loop.
                  >
                  > --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
                  >> Great story --- I will have to rent a copy of that flick. I like
                  > comedy.
                  >> You put the ferrite loop antenna from the little radio into the
                  >> S-a-Tenna? Or did you use that as the coupler for outside?
                  >>
                  >> Sorry if I am a little dense and did not quite get the picture...
                  >> I am getting the notion you put the ferrite bar inside as the
                  >> pickup loop and then hard wired the thing to the antenna jack
                  >> on the receiver. Or is it the other way around...?
                  >>
                  >> /////////////// Richards ///////////////
                  >> ==============================================
                  >>
                  >> mhatlau wrote:
                  >> and pulled the one inch ferite
                  >>> antenna out of it. Then ripped out the useless miniature audio jack
                  >>> and hooked a BNC connector up to the ferite loop. Cut a hole in the
                  >>> back of the Select-A-Tenna so I could put it inside, about three
                  >>> inches from the loop and at right angles to it with Epoxy.
                  >> =============================================
                  >>
                  >
                  >
                  >
                  >
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                  >
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                  > http://ph.groups.yahoo.com/group/loopantennas/photos
                  >
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                  >
                  >
                • airchecklover
                  ... Hey Mark; (tongue firmly in cheek...) You know that CCrane invented the Select-A-Tenna with the pickup loop inside? It says so right on their website.
                  Message 8 of 20 , Dec 4, 2007
                    --- In loopantennas@yahoogroups.com, "mhatlau" <mhuss1@...> wrote:
                    >
                    > I have the one with the external jack on it. I opened it up to ...


                    Hey Mark;

                    (tongue firmly in cheek...)

                    You know that CCrane invented the Select-A-Tenna with the pickup loop
                    inside? It says so right on their website. Hey, if it's in print it
                    must be true. Soooooo, I'm thinking since you have improved on ...
                    err ... "their" design, why not write them? I mean, using their
                    logic, they would add your name as co-inventor, right??!!?? :))


                    Mark
                  • jefeickert
                    I am looking for the loop antenna that is about 2 wide and is about 8-12 dia. and it sits close to a radio bring in stations. I think they run around $60.00
                    Message 9 of 20 , Dec 1, 2008
                      I am looking for the loop antenna that is about 2" wide and is about 8-12" dia.
                      and it sits close to a radio bring in stations.
                      I think they run around $60.00
                      JIM
                    • Gary Pewitt
                      Jim, do a google search for Select-A-Tenna I see one on Amazon.com but it s $99.00 which I think is ridiculous. I think I paid about $12.00 for mine used. I
                      Message 10 of 20 , Dec 1, 2008
                        Jim, do a google search for Select-A-Tenna I see one on Amazon.com but
                        it's $99.00 which I think is ridiculous.
                        I think I paid about $12.00 for mine used.
                        I also see a Terk Technology version from $28.29.

                        My select-a-tenna works very well with an ordinary AB broadcast receiver
                        . When I tried it with my SuperRadio III it didn't help much as the
                        radio has an rf amp and doesn't need the help.
                        There is also a powered Super Select-A-Tenna but it costs $199.95 new.
                        Should work quite well but I've never tried it.
                        Lots more hits on that search. Good luck. 73 Gary N9ZSV





                        jefeickert wrote:
                        >
                        > I am looking for the loop antenna that is about 2" wide and is about
                        > 8-12" dia.
                        > and it sits close to a radio bring in stations.
                        > I think they run around $60.00
                        > JIM
                        >
                        >
                      • jefeickert
                        WOW They sure are costly. Maybe aI will go with a long wire on the Kenwood R1000-
                        Message 11 of 20 , Dec 1, 2008
                          WOW They sure are costly. Maybe aI will go with a long wire on the Kenwood R1000-
                          >
                          >
                          >
                          > >
                          >
                        • Jim Dunstan
                          ... Hi, You could build your own ... such a form could be made from a crochet hoop which come in various sizes and can be found in craft stores. However, I
                          Message 12 of 20 , Dec 1, 2008
                            At 03:03 AM 12/2/2008 +0000, you wrote:

                            >WOW They sure are costly. Maybe aI will go with a long wire on the Kenwood
                            >R1000-

                            Hi,

                            You could build your own ... such a form could be made from a crochet hoop
                            which come in various sizes and can be found in craft stores. However, I
                            believe the Kenwood R1000 does not have a ferrite tuned antenna and would
                            not work with just close proximity to the loop. You would have to include
                            a second pickup loop on the form. Some of the commercial models include
                            this feature and some do not.

                            Jim
                          • Dirk
                            I m looking for plans for a full wave 160m loop for my back yard here in Illinois. I d probably load it up for other bands but want to get into 160m. Any
                            Message 13 of 20 , Feb 13, 2009
                              I'm looking for plans for a full wave 160m loop for my back yard here
                              in Illinois. I'd probably load it up for other bands but want to get
                              into 160m. Any ideas?
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