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Re: New file uploaded to loopantennas

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  • n2chi
    ... 1530+, claiming it had 18 dB greater gain.
    Message 1 of 28 , Feb 1, 2007
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      >>>...they mentioned the ALA 330, but also pushed the lower cost ALA
      1530+, claiming it had 18 dB greater gain.<<<

      That's interesting. I bought the old 1530 about a year ago. So the
      "plus" has that much more gain? Sounds like a good deal. I know
      that by the time I finished my not-so-rigorous research on the
      Internet last year, trying to choose between the 1530 (old) and the
      330, I decided that for my purposes and favorite frequencies they were
      about the same. If I remember correctly...and I don't always....I
      think the 1530 seemed to produce better results lower in the spectrum
      and the 330 better up around 20Mhz where I seldom go. At any rate,
      my 1530 does very well at my location from LF to SW, including 21 Mhz,
      so I'm pleased. And....most important to me...it all but eliminated RF
      noise.
      Dave





      --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
      >
      > Yes. I did ask Wellbrook about it. Also about the use
      > of a compacted loop as in our friend's application. I
      > thought this model used a loop of about 3-5 meters on a
      > side. I am wondering how I would deploy such a 5-meter
      > on a side loop in my new backyard... I liked the way
      > our compatriot compacted the loop and asked Wellbrook
      > if it would perform as well as the original design.
      >
      > I will post up what they say, if anything. So far, they
      > are kinda pushing me to the 1530+ as the one to get, as
      > opposed to the more expensive ALA 330. (I asked them to
      > identify their best SW antenna, indicating I only occasionally
      > look for MW DX) and they mentioned the ALA 330, but also
      > pushed the lower cost ALA 1530+, claiming it had 18 dB
      > greater gain.
      >
      > So... I cannot make up my mind.
      >
      > ////////// Richards /////////
      > =======================================================
      >
      > nonlinear@... wrote:
      >
      > > Have you tried asking wellbrook directly?
      >
    • Rob Moore
      Hi Richards, I think the ALA-100 would be more flexible for you and probably perform better than the ALA-1530 if you don t mind building up the antenna. You
      Message 2 of 28 , Feb 1, 2007
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        Hi Richards,

        I think the ALA-100 would be more flexible for you and probably
        perform better than the ALA-1530 if you don't mind building up the
        antenna. You can play with a compact design like I did, so you can
        rotate it, or you can make up a larger single loop. It also costs
        less than the ALA-1530. I haven't evaluated the 1530+ and would like
        to, but I don't have one available right now. Of course, the
        ALA-1530, ALA-1530+ and ALA-330 are all great antennas too but have a
        smaller capture area. That may be why the ALA-100 seems to outperform
        the ALA-1530. And I'm sure that locating the antenna well away from
        the house makes a large difference in the noise pickup. No problems
        with light dimmers, etc.

        I'll be interested to see what Wellbrook says about the compact loop
        design so please let us know when they reply.

        Regards,
        Rob


        --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
        >
        > Yes. I did ask Wellbrook about it. Also about the use
        > of a compacted loop as in our friend's application. I
        > thought this model used a loop of about 3-5 meters on a
        > side. I am wondering how I would deploy such a 5-meter
        > on a side loop in my new backyard... I liked the way
        > our compatriot compacted the loop and asked Wellbrook
        > if it would perform as well as the original design.
        >
        > I will post up what they say, if anything. So far, they
        > are kinda pushing me to the 1530+ as the one to get, as
        > opposed to the more expensive ALA 330. (I asked them to
        > identify their best SW antenna, indicating I only occasionally
        > look for MW DX) and they mentioned the ALA 330, but also
        > pushed the lower cost ALA 1530+, claiming it had 18 dB
        > greater gain.
        >
        > So... I cannot make up my mind.
        >
        > ////////// Richards /////////
        > =======================================================
        >
        > nonlinear@... wrote:
        >
        > > Have you tried asking wellbrook directly?
        >
      • Rob Moore
        RIchards, I bellieve that the main benefit of the ALA-1530+ is the extended frequency range - to 100Mhz as quoted on the Wellbrook site. 18db additional
        Message 3 of 28 , Feb 1, 2007
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          RIchards,

          I bellieve that the main benefit of the ALA-1530+ is the extended
          frequency range - to 100Mhz as quoted on the Wellbrook site. 18db
          "additional" gain over the ALA-1530 doesn't sound right, considering
          that the ALA-1530 has around 12db of gain if I remember correctly.
          They also talk about increased IP3 strong signalimage rejection for
          the ALA-1530+.

          Rob

          --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
          ... but also
          > pushed the lower cost ALA 1530+, claiming it had 18 dB
          > greater gain.
          >
          > So... I cannot make up my mind.
          >
          > ////////// Richards /////////
          > =======================================================
          >
          > nonlinear@... wrote:
          >
          > > Have you tried asking wellbrook directly?
          >
        • aimo ruoho
          Hi! Why not buy them all? Anyway, the Chinese will copy them all very soon, and they will cost a lot less! Aimo nonlinear@rogers.com wrote: the 5
          Message 4 of 28 , Feb 1, 2007
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            Hi!
            Why not buy them all?
            Anyway, the Chinese will copy them all very soon, and they will cost a lot less!
            Aimo

            nonlinear@... wrote: the 5 metre loop looks a bit tough

            what about the 1 metre loop but mounted higher up and still on a rotator?

            does the height equalize wrt the 5 metre's DX ability?

            if you spending these kind of bucks you want the right decision for sure!!

            (btw:always wanted a wellbrook loop but would cost about 500$ CDN I figure to get one here so I just dream)

            best
            Paul

            ----- Original Message ----
            From: Richards <jruing@...>
            To: loopantennas@yahoogroups.com
            Sent: Wednesday, January 31, 2007 11:59:57 PM
            Subject: Re: [loopantennas] Re: New file uploaded to loopantennas

            Yes. I did ask Wellbrook about it. Also about the use
            of a compacted loop as in our friend's application. I
            thought this model used a loop of about 3-5 meters on a
            side. I am wondering how I would deploy such a 5-meter
            on a side loop in my new backyard... I liked the way
            our compatriot compacted the loop and asked Wellbrook
            if it would perform as well as the original design.

            I will post up what they say, if anything. So far, they
            are kinda pushing me to the 1530+ as the one to get, as
            opposed to the more expensive ALA 330. (I asked them to
            identify their best SW antenna, indicating I only occasionally
            look for MW DX) and they mentioned the ALA 330, but also
            pushed the lower cost ALA 1530+, claiming it had 18 dB
            greater gain.

            So... I cannot make up my mind.

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

            nonlinear@rogers. com wrote:

            > Have you tried asking wellbrook directly?

            [Non-text portions of this message have been removed]






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          • nonlinear@rogers.com
            Hi Amio no doubts you are right yet maybe they might invent some new antenna along the way best Paul ... From: aimo ruoho To:
            Message 5 of 28 , Feb 1, 2007
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              Hi Amio
              no doubts you are right yet maybe they might invent some new antenna along the way

              best
              Paul

              ----- Original Message ----
              From: aimo ruoho <aimounto@...>
              To: loopantennas@yahoogroups.com
              Sent: Thursday, February 1, 2007 4:54:55 PM
              Subject: Re: [loopantennas] Re: New file uploaded to loopantennas

              Hi!
              Why not buy them all?
              Anyway, the Chinese will copy them all very soon, and they will cost a lot less!
              Aimo

              nonlinear@rogers. com wrote: the 5 metre loop looks a bit tough

              what about the 1 metre loop but mounted higher up and still on a rotator?

              does the height equalize wrt the 5 metre's DX ability?

              if you spending these kind of bucks you want the right decision for sure!!

              (btw:always wanted a wellbrook loop but would cost about 500$ CDN I figure to get one here so I just dream)

              best
              Paul

              ----- Original Message ----
              From: Richards <jruing@ameritech. net>
              To: loopantennas@ yahoogroups. com
              Sent: Wednesday, January 31, 2007 11:59:57 PM
              Subject: Re: [loopantennas] Re: New file uploaded to loopantennas

              Yes. I did ask Wellbrook about it. Also about the use
              of a compacted loop as in our friend's application. I
              thought this model used a loop of about 3-5 meters on a
              side. I am wondering how I would deploy such a 5-meter
              on a side loop in my new backyard... I liked the way
              our compatriot compacted the loop and asked Wellbrook
              if it would perform as well as the original design.

              I will post up what they say, if anything. So far, they
              are kinda pushing me to the 1530+ as the one to get, as
              opposed to the more expensive ALA 330. (I asked them to
              identify their best SW antenna, indicating I only occasionally
              look for MW DX) and they mentioned the ALA 330, but also
              pushed the lower cost ALA 1530+, claiming it had 18 dB
              greater gain.

              So... I cannot make up my mind.

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

              nonlinear@rogers. com wrote:

              > Have you tried asking wellbrook directly?

              [Non-text portions of this message have been removed]

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            • Richards
              Hi Rob -- good points all around. Here is the answer from Mr. Andy Aiken of Wellbrook Communications: Dear Richard, I believe Guy Atkins was the first person
              Message 6 of 28 , Feb 2, 2007
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                Hi Rob -- good points all around. Here is the answer from
                Mr. Andy Aiken of Wellbrook Communications:

                Dear Richard,

                I believe Guy Atkins was the first person to used the
                multi-turn construction. This should be ideal for MW,HF
                and allows for loop rotation for nulling. However, for
                higher sensitivity a larger single turn loop is required.
                A spiral may provide better nulls, but I don't know if
                this has been tried? Also spiral may present some
                construction challenges that may not be justified
                with the performance!

                Kind regards

                Andy

                SO ... I wonder how I might get that greater sensitivity by
                hanging it as a larger loop. My back yard is not all that
                big, and I do not have any towers to hang it from. The specs
                call for a loop that is 2 to 5 meters on a side, so how would
                one hang a 40 to 60 foot loop in his suburban back yard? I
                think it is intended to hand vertically, so a horizontal loop
                around, say, the outside of my roof line, or in the attic, or
                around a fence top, would not be best. Do I just settle for
                a 20 foot loop in a triangle, pennant, shape maybe, hanging
                from two trees as the outer longer side points, with a lower
                middle point? (like a very wide V)

                Maybe I just make the smaller type loop and figure it cannot
                be any worse then the 1550+ hula hoop loop (around 1 meter
                diameter) and save money... I can always remake the loop
                into something bigger later... or maybe I make a
                somewhat bigger compromise loop out of PVC, say maybe 2
                meters on each side, to get a loop at least as large
                as the smallest loop stated in the specs.

                Ohhhh.... Arghhhh.... What to do?

                ////////////// Richards /////////////////
                ======================================================
              • Rob Moore
                Hi Richards, I know the quandry you re in. Let us know what you try. Regards, Rob
                Message 7 of 28 , Feb 2, 2007
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                  Hi Richards,

                  I know the quandry you're in. Let us know what you try.

                  Regards,
                  Rob


                  --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
                  >
                  > Hi Rob -- good points all around. Here is the answer from
                  > Mr. Andy Aiken of Wellbrook Communications:
                  >
                  > Dear Richard,
                  >
                  > I believe Guy Atkins was the first person to used the
                  > multi-turn construction. This should be ideal for MW,HF
                  > and allows for loop rotation for nulling. However, for
                  > higher sensitivity a larger single turn loop is required.
                  > A spiral may provide better nulls, but I don't know if
                  > this has been tried? Also spiral may present some
                  > construction challenges that may not be justified
                  > with the performance!
                  >
                  > Kind regards
                  >
                  > Andy
                  >
                  > SO ... I wonder how I might get that greater sensitivity by
                  > hanging it as a larger loop. My back yard is not all that
                  > big, and I do not have any towers to hang it from. The specs
                  > call for a loop that is 2 to 5 meters on a side, so how would
                  > one hang a 40 to 60 foot loop in his suburban back yard? I
                  > think it is intended to hand vertically, so a horizontal loop
                  > around, say, the outside of my roof line, or in the attic, or
                  > around a fence top, would not be best. Do I just settle for
                  > a 20 foot loop in a triangle, pennant, shape maybe, hanging
                  > from two trees as the outer longer side points, with a lower
                  > middle point? (like a very wide V)
                  >
                  > Maybe I just make the smaller type loop and figure it cannot
                  > be any worse then the 1550+ hula hoop loop (around 1 meter
                  > diameter) and save money... I can always remake the loop
                  > into something bigger later... or maybe I make a
                  > somewhat bigger compromise loop out of PVC, say maybe 2
                  > meters on each side, to get a loop at least as large
                  > as the smallest loop stated in the specs.
                  >
                  > Ohhhh.... Arghhhh.... What to do?
                  >
                  > ////////////// Richards /////////////////
                  > ======================================================
                  >
                • Richards
                  (Rob -- Read this as ooooozing with feigned sarcasm:) Oh... yeah... you offer a little sympathy... or is it empathy... whatever... Still I lament the lack of
                  Message 8 of 28 , Feb 6, 2007
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                    (Rob -- Read this as ooooozing with feigned sarcasm:)

                    Oh... yeah... you offer a little sympathy...
                    or is it empathy... whatever...

                    Still I lament the lack of solid advice !! ;-)

                    OK - so I poke some fun, but just knowing someone appreciates
                    the difficulty of my dilemma helps me know I am at least
                    considering the right notions.

                    I will certainly let you know what I do.

                    /////////////////// THANKS -- Richards //////////////

                    Rob Moore wrote:
                    > Hi Richards,
                    >
                    > I know the quandry you're in. Let us know what you try.
                  • Rob Moore
                    Hi Richards, Sarcasm notwithstanding, if it was me, based on what I ve found out abut the ALA-100 so far, I d go with that. It s flexible, fairly sensitive
                    Message 9 of 28 , Feb 6, 2007
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                      Hi Richards,

                      Sarcasm notwithstanding, if it was me, based on what I've found out
                      abut the ALA-100 so far, I'd go with that. It's flexible, fairly
                      sensitive and potentially very quiet. You can make a large 1 turn
                      loop, or a smaller multi-turn loop. It's compact enough so that you
                      can bring it, a roll of wire and your portable radio on a trip and
                      be set up and ready to go in a half an hour or so. What else is
                      there to say?

                      Regards,
                      Rob

                      --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
                      >
                      > (Rob -- Read this as ooooozing with feigned sarcasm:)
                      >
                      > Oh... yeah... you offer a little sympathy...
                      > or is it empathy... whatever...
                      >
                      > Still I lament the lack of solid advice !! ;-)
                      >
                      > OK - so I poke some fun, but just knowing someone appreciates
                      > the difficulty of my dilemma helps me know I am at least
                      > considering the right notions.
                      >
                      > I will certainly let you know what I do.
                      >
                      > /////////////////// THANKS -- Richards //////////////
                      >
                      > Rob Moore wrote:
                      > > Hi Richards,
                      > >
                      > > I know the quandry you're in. Let us know what you try.
                      >
                    • Richards
                      Gee ... you make it sound pretty flexible. I am now working on a couple of things: First - moving to a new qth - very upsetting - I HATE that feeling of
                      Message 10 of 28 , Feb 7, 2007
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                        Gee ... you make it sound pretty flexible. I am now working
                        on a couple of things:

                        First - moving to a new qth - very upsetting - I HATE
                        that feeling of being unsettled and living out of boxes;

                        Second - I am conjuring up images of how I might
                        make a relatively small loop, maybe two-meters-on-a-side,
                        that I could mount out back on a pole or just off the corner
                        of my deck;

                        Third - inventing some huge lie to tell the neighbors so
                        they do not realize what it is.


                        I will keep you posted on my progress... or lack thereof...
                        Thanks for the nice replies. //// Richards ////
                        =========================================================

                        Rob Moore wrote:
                        > Hi Richards,
                        >
                        > Sarcasm notwithstanding, if it was me, based on what I've found out
                        > abut the ALA-100 so far, I'd go with that.
                      • n2chi
                        ... Or both, since you supply the wire. Can the head unit at the antenna be easily disconnected and connected to another loop? Or, how about an arrangement
                        Message 11 of 28 , Feb 7, 2007
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                          >>>You can make a large 1 turn loop, or a smaller multi-turn loop.<<<

                          Or both, since you supply the wire. Can the head unit at the antenna
                          be easily disconnected and connected to another loop? Or, how about
                          an arrangement where the small multi-turn loop is bypassed with a
                          switch so that the coax then continues to a large loop elsewhere in
                          the back yard. Would that work? If so, then how about multiple
                          configurations of loops attached to a remote multi-antenna coax
                          switch where the common comes back to the shack from several loops
                          through the head unit.
                          Dave


                          --- In loopantennas@yahoogroups.com, "Rob Moore" <rmoore5@...> wrote:
                          >
                          > Hi Richards,
                          >
                          > Sarcasm notwithstanding, if it was me, based on what I've found out
                          > abut the ALA-100 so far, I'd go with that. It's flexible, fairly
                          > sensitive and potentially very quiet. You can make a large 1 turn
                          > loop, or a smaller multi-turn loop. It's compact enough so that
                          you
                          > can bring it, a roll of wire and your portable radio on a trip and
                          > be set up and ready to go in a half an hour or so. What else is
                          > there to say?
                          >
                          > Regards,
                          > Rob
                          >
                          > --- In loopantennas@yahoogroups.com, Richards <jruing@> wrote:
                          > >
                          > > (Rob -- Read this as ooooozing with feigned sarcasm:)
                          > >
                          > > Oh... yeah... you offer a little sympathy...
                          > > or is it empathy... whatever...
                          > >
                          > > Still I lament the lack of solid advice !! ;-)
                          > >
                          > > OK - so I poke some fun, but just knowing someone appreciates
                          > > the difficulty of my dilemma helps me know I am at least
                          > > considering the right notions.
                          > >
                          > > I will certainly let you know what I do.
                          > >
                          > > /////////////////// THANKS -- Richards //////////////
                          > >
                          > > Rob Moore wrote:
                          > > > Hi Richards,
                          > > >
                          > > > I know the quandry you're in. Let us know what you try.
                          > >
                          >
                        • Rob Moore
                          Hi Richards, Just make it out of PVC pipe like I did. With 2 meters on a side, two turns about four inches apart would be 16 meters, which is within the range
                          Message 12 of 28 , Feb 7, 2007
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                            Hi Richards,

                            Just make it out of PVC pipe like I did. With 2 meters on a side,
                            two turns about four inches apart would be 16 meters, which is
                            within the range of size that Wellbrook recommends. Of course, if
                            you like BCB DXing or LW, you could go longer.

                            Rob

                            --- In loopantennas@yahoogroups.com, Richards <jruing@...> wrote:
                            >
                            > Gee ... you make it sound pretty flexible. I am now working
                            > on a couple of things:
                            >
                            > First - moving to a new qth - very upsetting - I HATE
                            > that feeling of being unsettled and living out of boxes;
                            >
                            > Second - I am conjuring up images of how I might
                            > make a relatively small loop, maybe two-meters-on-a-side,
                            > that I could mount out back on a pole or just off the corner
                            > of my deck;
                            >
                            > Third - inventing some huge lie to tell the neighbors so
                            > they do not realize what it is.
                            >
                            >
                            > I will keep you posted on my progress... or lack thereof...
                            > Thanks for the nice replies. //// Richards ////
                            > =========================================================
                            >
                            > Rob Moore wrote:
                            > > Hi Richards,
                            > >
                            > > Sarcasm notwithstanding, if it was me, based on what I've found
                            out
                            > > abut the ALA-100 so far, I'd go with that.
                            >
                          • gandalfg8@aol.com
                            In a message dated 12/08/2008 02:34:20 GMT Daylight Time, dunstan@confederationc.on.ca writes: I found the picture very informative and interesting ... I have
                            Message 13 of 28 , Aug 12, 2008
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                              In a message dated 12/08/2008 02:34:20 GMT Daylight Time,
                              dunstan@... writes:

                              I found the picture very informative and interesting ... I have never seen
                              'basket weave' done this way. In one way it is the same loop as mine ...
                              but i fastened all the dowels by screwing them to a circular disk. It is
                              not clear from the photo ... how do you fasten the dowels to the embroidery
                              hoop ? I assume you drill a hole and pass through a screw of some
                              sort. The weave then takes place on either side of the embroidery hoop.


                              ----------
                              Hi Jim

                              From the photo I would say that the dowels have slots cut in them to fit
                              over the hoop and then screwed or glued in place, perhaps better the latter as
                              that would avoid any metal content in the loop support.

                              If you look closely you will see that the dowels protrude from one side of
                              the loop only so the weave is also just on one side.

                              It's certainly an attractive design.

                              regards

                              Nigel
                              GM8PZR







                              [Non-text portions of this message have been removed]
                            • Chris Trask
                              ... A few people asked about where to obtain some of the parts for this, such as the varactors and transformer cores. Best place I could think of was Dan s
                              Message 14 of 28 , Aug 30, 2008
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                                >
                                > File : /Varactor Tuned Loop Antenna.pdf
                                > Uploaded by : chris3trask <christrask@...>
                                > Description : A simple varactor-tuned loop antenna with interchangeable
                                > antenna elements
                                >

                                A few people asked about where to obtain some of the parts for this,
                                such as the varactors and transformer cores. Best place I could think of
                                was Dan's Small Parts:

                                <http://www.danssmallpartsandkits.net>

                                With a couple of minor substitutions, he has the varactors, cores, and
                                magnet wire. The remaining parts are fairly common. He also has a pair of
                                reduction drives which can be used on the tuning control if desired. I put
                                all of this on a new page at the end of the document.

                                I would be interested in hearing from others overseas about part sources
                                so that they can be added to the list. I'm also trying to find someone who
                                would make parts kits available, but haven't heard anything back as of yet.

                                Chris

                                ,----------------------. High Performance Mixers and
                                / What's all this \ Amplifiers for RF Communications
                                / extinct stuff, anyhow? /
                                \ _______,--------------' Chris Trask / N7ZWY
                                _ |/ Principal Engineer
                                oo\ Sonoran Radio Research
                                (__)\ _ P.O. Box 25240
                                \ \ .' `. Tempe, Arizona 85285-5240
                                \ \ / \
                                \ '" \ IEEE Senior Member #40274515
                                . ( ) \
                                '-| )__| :. \ Email: christrask@...
                                | | | | \ '. http://www.home.earthlink.net/~christrask
                                c__; c__; '-..'>.__

                                Graphics by Loek Frederiks
                              • Chris Trask
                                ... I recall seeing a similar instrument for testing capacitors that appeared in Popular Electronics or some other magazine about 30-35 years ago. It used the
                                Message 15 of 28 , Jan 13, 2009
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                                  >
                                  > File : /UsefulTestEquipment/555InductanceMeter03.gif
                                  > Uploaded by : alienrelics <alienrelics@...>
                                  > Description : Dual 555 timer inductance meter. Preliminary schematic,
                                  > not tested yet. Critique?
                                  >

                                  I recall seeing a similar instrument for testing capacitors that appeared in Popular Electronics or some other magazine about 30-35 years ago. It used the same 555 format where the first one was a clock oscillator and the second was a pulse width modulator. They work fairly well given their simplicity. I made one and used it for years until I obtained a cheap LCR meter.

                                  They can be a bit more accurate if the zero pot is replaced with a third 555 of the same circuit as the second, where a fixed reference inductor (or inductors) is used. This will cancel out the unavoidable errors from the finite switching time of the 555.



                                  Chris

                                  ,----------------------. High Performance Mixers and
                                  / What's all this \ Amplifiers for RF Communications
                                  / extinct stuff, anyhow? /
                                  \ _______,--------------' Chris Trask / N7ZWY
                                  _ |/ Principal Engineer
                                  oo\ Sonoran Radio Research
                                  (__)\ _ P.O. Box 25240
                                  \ \ .' `. Tempe, Arizona 85285-5240
                                  \ \ / \
                                  \ '" \ IEEE Senior Member #40274515
                                  . ( ) \
                                  '-| )__| :. \ Email: christrask@...
                                  | | | | \ '. http://www.home.earthlink.net/~christrask
                                  c__; c__; '-..'>.__

                                  Graphics by Loek Frederiks
                                • Steve
                                  ... that appeared in Popular Electronics or some other magazine about 30-35 years ago. It used the same 555 format where the first one was a clock oscillator
                                  Message 16 of 28 , Jan 13, 2009
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                                    --- In loopantennas@yahoogroups.com, Chris Trask <christrask@...> wrote:
                                    >
                                    >
                                    > >
                                    > > File : /UsefulTestEquipment/555InductanceMeter03.gif
                                    > > Uploaded by : alienrelics <alienrelics@...>
                                    > > Description : Dual 555 timer inductance meter. Preliminary schematic,
                                    > > not tested yet. Critique?
                                    > >
                                    >
                                    > I recall seeing a similar instrument for testing capacitors
                                    that appeared in Popular Electronics or some other magazine about
                                    30-35 years ago. It used the same 555 format where the first one was
                                    a clock oscillator and the second was a pulse width modulator. They
                                    work fairly well given their simplicity. I made one and used it for
                                    years until I obtained a cheap LCR meter.
                                    >

                                    My wife tried to convince me to patent these, I explained to her that
                                    these are quite obvious to those "skilled in the arts", which is one
                                    of the tests something must pass to get a patent. Of course, recent
                                    history shows that -isn't- true. Patents on using a mousewheel, on
                                    scrolling, storing documents on websites, etc. Ugh.

                                    > They can be a bit more accurate if the zero pot is replaced
                                    with a third 555 of the same circuit as the second, where a fixed
                                    reference inductor (or inductors) is used. This will cancel out the
                                    unavoidable errors from the finite switching time of the 555.
                                    >

                                    I'm not sure how that is more accurate unless you mean to avoid
                                    checking the zero set when you use it. On my 555 cap meter, the zero
                                    set is a front panel control. Calibration is an internal 20 turn pot.

                                    Would you then adjust the reference inductor for zero? It seems to me
                                    that temperature induced drift in an adjustable inductor would be
                                    greater than that of a potentiometer and the 555 timer itself.

                                    One of the uses I have for the cap meter is a fairly sensitive
                                    differential capacitance sensor that does use a third 555 just as you
                                    describe. In that situation, zero set isn't performed regularly and
                                    this way drift due to the 555 is canceled out.

                                    Steve Greenfield
                                  • everettsharp74
                                    Sorry about, I tried uploading that file in pdf, but for some reason I could not open the file, so I deleted it. So I just uploaded it again, but in MS Word.
                                    Message 17 of 28 , Mar 8, 2013
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                                      Sorry about, I tried uploading that file in pdf, but for some reason I could not open the file, so I deleted it. So I just uploaded it again, but in MS Word.
                                       
                                      Everett N8CNP
                                       
                                      In a message dated 3/8/2013 3:08:24 P.M. Central Standard Time, loopantennas@yahoogroups.com writes:
                                       


                                      Hello,

                                      This email message is a notification to let you know that
                                      a file has been uploaded to the Files area of the loopantennas
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                                      File : /Matching transformers using Binocular Core.docx
                                      Uploaded by : everettsharp74 <everettsharp@...>
                                      Description : Matching Transformer info usinga Binocular Core

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                                    • loopantennas@yahoogroups.com
                                      Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the loopantennas group. File :
                                      Message 18 of 28 , Apr 3
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                                        Hello,


                                        This email message is a notification to let you know that
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                                        File : /80Meterhorizontalloop.pdf
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                                        Description : 80 Meter Horizontal Loop Antenna


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                                      • loopantennas@yahoogroups.com
                                        Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the loopantennas group. File :
                                        Message 19 of 28 , Apr 20
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                                          Hello,


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                                          File : /IMG_20140926_061922.jpg
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                                          Description : 600 mm Loop


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