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Re: [loopantennas] Salvaged Variable Condenser?

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  • Keith Davis
    Wow......I guess I am not understanding the power involved in an antenna if it will actually ARC THROUGH the poly separators. I read someplace that hanging a
    Message 1 of 16 , Aug 7, 2010
      Wow......I guess I am not understanding the power involved in an antenna if it will actually ARC THROUGH the poly separators.

      I read someplace that hanging a wire in your back yard and wiring it to ground via a salvaged LED will actually light the diode. I have not tried this but plan to soon.

      keith
    • cannonmandolin
      OK, one of you all just made me smarter. Transmit antennas can develop voltage and arc, not USUALLY receiving antennas. Whew.... In about six decades i ve
      Message 2 of 16 , Aug 7, 2010
        OK, one of you all just made me smarter. Transmit antennas can develop voltage and arc, not USUALLY receiving antennas. Whew....

        In about six decades i've managed to learn a lot of stuff.....just not stuff about radios. I've been too busy making a living I guess.
        As usual, you guys are bailing me out. THANKS.

        If it cools down much under 95 this evening I'm going to take my new Kaito out on the patio and hang it as high as I can and see what's available to listen to. Hopefully the 'skeeters are not too hungry tonight.

        keith
      • Dick Bingham
        I have heard of people _CHARGING_ car batteries using a long-wire antenna, a spark-plug, an ignition-coil and connecting the battery to ground. Have not
        Message 3 of 16 , Aug 7, 2010
          I have heard of people _CHARGING_ car batteries using a long-wire antenna, a
          spark-plug, an ignition-coil and connecting the battery to ground. Have not
          investigated this but it sounds reasonable... Check it out on GOOGLE...

          73 - Dick/w7wkr CN98pi



          On Sat, Aug 7, 2010 at 2:01 PM, Keith Davis <cannonmandolin@...>wrote:

          >
          >
          > Wow......I guess I am not understanding the power involved in an antenna if
          > it will actually ARC THROUGH the poly separators.
          >
          > I read someplace that hanging a wire in your back yard and wiring it to
          > ground via a salvaged LED will actually light the diode. I have not tried
          > this but plan to soon.
          >
          > keith
          >
          >
          >



          --
          Dick Bingham - W7WKR CN98pi
          Stehekin, WA
          Located in "The Alps of America"


          [Non-text portions of this message have been removed]
        • John Kolb
          While in the Navy, we could light small florescent tubes from our receiving antennas, but that was with two 500 watt transmitters continuously keyed, and
          Message 4 of 16 , Aug 7, 2010
            While in the Navy, we could light small florescent tubes from our
            receiving antennas, but that was with
            two 500 watt transmitters continuously keyed, and spacing less than
            the length of the ship. I wouldn't
            expect to light an LED from a receive antenna unless you are within a
            few blocks of a broadcast transmitter.

            Likewise, for receive use, a variable cap with poly separators should fine.

            John

            At 02:01 PM 8/7/2010, you wrote:
            >Wow......I guess I am not understanding the power involved in an
            >antenna if it will actually ARC THROUGH the poly separators.
            >
            >I read someplace that hanging a wire in your back yard and wiring it
            >to ground via a salvaged LED will actually light the diode. I have
            >not tried this but plan to soon.
            >
            >keith
          • legonedijk
            ... Keith, Making a varible condensor is great fun in my opinion. Ofcourse you can buy the nessesary components. Starting build your own most simplified
            Message 5 of 16 , Aug 8, 2010
              --- In loopantennas@yahoogroups.com, "cannonmandolin" <cannonmandolin@...> wrote:
              >
              > I can get a used variable condenser from an old radio, but it is one of the small ones with leaves of polyethylene between the metal plates. Can this be used in making a tuned loop? most specs call for an "air capacitor", but in salvage terms, at least in my life and work, they are quite rare.
              >
              > I can see now that actually listening to the radio and keeping a log is just a small part of the whole picture, and perhaps a larger part is planning for, talking about, reading up and then actually building an antenna. heh heh heh So, it's about like fly fishing in that the fly tying, reel lube, rod building, wader fixing, etc far outweighs the time we are allowed to spend on the stream.
              >
              > keith
              >
              Keith,
              Making a varible condensor is great fun in my opinion.
              Ofcourse you can buy the nessesary components.
              Starting build your own most simplified receiver
              is fun and still students do that....
              http://www.youtube.com/watch?v=AWL7hLEVSHQ

              Google for "selfmade variable condensor" and "crystal radio".

              Have fun !!!

              Regards:
              jan
            • cannonmandolin
              I m sold on Loops now I guess. I got outside last evening and humg my new Kaito on a bamboo stick about 20 feet long and let the lead trail down to me on the
              Message 6 of 16 , Aug 8, 2010
                I'm sold on Loops now I guess. I got outside last evening and humg my new Kaito on a bamboo stick about 20 feet long and let the lead trail down to me on the patio. I was hearing stations I've never heard before, and the tuning wheel, though pretty sensitive, was doing wonders.

                Now I'll have to dig in and figure out where to get some copper and build my own, permanent OUTSIDE loop.

                keith
              • alienrelics
                Well, that s gotten twisted in the telling and retelling. Power harvesting has been a hot item lately, but not to charge car batteries. EDN, Design News, or EE
                Message 7 of 16 , Aug 8, 2010
                  Well, that's gotten twisted in the telling and retelling.

                  Power harvesting has been a hot item lately, but not to charge car batteries. EDN, Design News, or EE Times had an article lately on using static electricity or random RF fields to charge very, very low power capacitor storage devices for use in extremely low duty cycle, extremely low power devices. We're talking microwatts/microjoules.

                  There is actually a spark gap oscillator involved in one design. A really, really tiny spark gap.

                  Steve Greenfield AE7HD

                  --- In loopantennas@yahoogroups.com, Dick Bingham <dick.bingham@...> wrote:
                  >
                  > I have heard of people _CHARGING_ car batteries using a long-wire antenna, a
                  > spark-plug, an ignition-coil and connecting the battery to ground. Have not
                  > investigated this but it sounds reasonable... Check it out on GOOGLE...
                  >
                  > 73 - Dick/w7wkr CN98pi
                  >
                  >
                  >
                  > On Sat, Aug 7, 2010 at 2:01 PM, Keith Davis <cannonmandolin@...>wrote:
                  >
                  > >
                  > >
                  > > Wow......I guess I am not understanding the power involved in an antenna if
                  > > it will actually ARC THROUGH the poly separators.
                  > >
                  > > I read someplace that hanging a wire in your back yard and wiring it to
                  > > ground via a salvaged LED will actually light the diode. I have not tried
                  > > this but plan to soon.
                  > >
                  > > keith
                  > >
                  > >
                  > >
                  >
                  >
                  >
                  > --
                  > Dick Bingham - W7WKR CN98pi
                  > Stehekin, WA
                  > Located in "The Alps of America"
                  >
                  >
                  > [Non-text portions of this message have been removed]
                  >
                • alienrelics
                  ... Wow, there are a lot of bad videos about making crystal radios on YouTube! Steve Greenfield AE7HD
                  Message 8 of 16 , Aug 8, 2010
                    --- In loopantennas@yahoogroups.com, "legonedijk" <legonedijk@...> wrote:
                    >
                    >
                    >
                    > --- In loopantennas@yahoogroups.com, "cannonmandolin" <cannonmandolin@> wrote:
                    > >
                    > > I can get a used variable condenser from an old radio, but it is one of the small ones with leaves of polyethylene between the metal plates. Can this be used in making a tuned loop? most specs call for an "air capacitor", but in salvage terms, at least in my life and work, they are quite rare.
                    > >
                    > > I can see now that actually listening to the radio and keeping a log is just a small part of the whole picture, and perhaps a larger part is planning for, talking about, reading up and then actually building an antenna. heh heh heh So, it's about like fly fishing in that the fly tying, reel lube, rod building, wader fixing, etc far outweighs the time we are allowed to spend on the stream.
                    > >
                    > > keith
                    > >
                    > Keith,
                    > Making a varible condensor is great fun in my opinion.
                    > Ofcourse you can buy the nessesary components.
                    > Starting build your own most simplified receiver
                    > is fun and still students do that....
                    > http://www.youtube.com/watch?v=AWL7hLEVSHQ
                    >
                    > Google for "selfmade variable condensor" and "crystal radio".
                    >

                    Wow, there are a lot of bad videos about making crystal radios on YouTube!

                    Steve Greenfield AE7HD
                  • Andy
                    ... Transmitting loop antennas, especially small ones, can have VERY high voltages and circulating currents even at moderate power levels. That s why some
                    Message 9 of 16 , Aug 8, 2010
                      > Wow......I guess I am not understanding the power involved in an antenna if it will actually ARC THROUGH the poly separators.

                      Transmitting loop antennas, especially small ones, can have VERY high
                      voltages and circulating currents even at moderate power levels.

                      That's why some people who make small transmitting loops go out of
                      their way to use thick pipe, vacuum capacitors, or devices that have
                      no sliding contacts, such as butterfly capacitors where there are no
                      moving parts (i.e., bearings) in the current path.

                      Receiving circuits? No such problem.
                    • pappy_hiram
                      ... Unless it gets struck by lightning, then it won t just be the capacitor arcing..... : ) Pappy Hiram
                      Message 10 of 16 , Aug 8, 2010
                        "cannonmandolin" wrote:
                        >
                        > OK, one of you all just made me smarter. Transmit antennas can develop voltage and arc, not USUALLY receiving antennas. Whew....

                        Unless it gets struck by lightning, then it won't just be the capacitor arcing..... : )

                        Pappy Hiram
                      • tenorman1952
                        Nobody, but nobody makes crystal radios like Dave Schmarder makes crystal radios!!! http://makearadio.com/crystal/index.php and Dave s Loops:
                        Message 11 of 16 , Aug 8, 2010
                          Nobody, but nobody makes crystal radios like Dave Schmarder makes crystal radios!!!

                          http://makearadio.com/crystal/index.php

                          and Dave's Loops:

                          http://makearadio.com/loops/index.php

                          You can't help but be impressed!

                          73
                          Paul - AE5JU

                          --- In loopantennas@yahoogroups.com, "alienrelics" <alienrelics@...> wrote:
                          >
                          >
                          >
                          > --- In loopantennas@yahoogroups.com, "legonedijk" <legonedijk@> wrote:
                          > >
                          > >
                          > >
                          > > --- In loopantennas@yahoogroups.com, "cannonmandolin" <cannonmandolin@> wrote:
                          > > >
                          > > > I can get a used variable condenser from an old radio, but it is one of the small ones with leaves of polyethylene between the metal plates. Can this be used in making a tuned loop? most specs call for an "air capacitor", but in salvage terms, at least in my life and work, they are quite rare.
                          > > >
                          > > > I can see now that actually listening to the radio and keeping a log is just a small part of the whole picture, and perhaps a larger part is planning for, talking about, reading up and then actually building an antenna. heh heh heh So, it's about like fly fishing in that the fly tying, reel lube, rod building, wader fixing, etc far outweighs the time we are allowed to spend on the stream.
                          > > >
                          > > > keith
                          > > >
                          > > Keith,
                          > > Making a varible condensor is great fun in my opinion.
                          > > Ofcourse you can buy the nessesary components.
                          > > Starting build your own most simplified receiver
                          > > is fun and still students do that....
                          > > http://www.youtube.com/watch?v=AWL7hLEVSHQ
                          > >
                          > > Google for "selfmade variable condensor" and "crystal radio".
                          > >
                          >
                          > Wow, there are a lot of bad videos about making crystal radios on YouTube!
                          >
                          > Steve Greenfield AE7HD
                          >
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