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Re: What type of capacitor is used for loop antenna?

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  • longjohn119
    ... You need a loop with more windings/inductance not a big cap. Having a way to measure the actual inductance is very helpful also .... Those run caps do make
    Message 1 of 14 , Apr 1, 2011
      --- In loopantennas@yahoogroups.com, "mowypt" <mowypt@...> wrote:
      >
      > With the loop I have, 6uf is what I need for below 1KHz and I don't know enough about capacitors. The one I have I guess it's called a "run" capacitor. It says 6uf 450 volts AC. I assume I need a different type of capacitor. Well thanks for your replies.
      >

      You need a loop with more windings/inductance not a big cap. Having a way to measure the actual inductance is very helpful also ....

      Those run caps do make excellent bipolar caps in speaker crossovers (The + and - marks are for phasing not DC polarity), especially for high power sound reinforcement speakers .... Otherwise not much use for them other than AC motors, if it's got a plastic case it's a start cap limited duty cycle, if it's got a metal case it's a run cap 100% duty cycle. Only the run caps make good crossover (Or AC coupling) caps although their size limits their applications mainly to speakers although I do have a circuit similar to this one by Dallas Lankford only using coil values (Crossover coils oversized that I took windings off of until I reach the desired inductance) tweaked to work with available start cap values. Mine will work on any amp up to 50 watts, you just plug it into a Speaker Out and then plug an external speaker into the filter.

      Elliptic Low Pass Audio Filters (Used to counter fading distortion on AM)
      http://www.kongsfjord.no/dl/Audio/ELPAFs.pdf

      JR
    • mowypt
      Thanks for your reply. Yes, I figured that I need more coil. I don t know, I read somewhere just add more capacitance but obviously that only works to a
      Message 2 of 14 , Apr 1, 2011
        Thanks for your reply. Yes, I figured that I need more coil. I don't know, I read somewhere "just add more capacitance" but obviously that only works to a point.

        --- In loopantennas@yahoogroups.com, "longjohn119" <some_oil_with_your_teaparty@...> wrote:
        >
        >
        >
        >
        >
        > --- In loopantennas@yahoogroups.com, "mowypt" <mowypt@> wrote:
        > >
        > > With the loop I have, 6uf is what I need for below 1KHz and I don't know enough about capacitors. The one I have I guess it's called a "run" capacitor. It says 6uf 450 volts AC. I assume I need a different type of capacitor. Well thanks for your replies.
        > >
        >
        > You need a loop with more windings/inductance not a big cap. Having a way to measure the actual inductance is very helpful also ....
        >
        > Those run caps do make excellent bipolar caps in speaker crossovers (The + and - marks are for phasing not DC polarity), especially for high power sound reinforcement speakers .... Otherwise not much use for them other than AC motors, if it's got a plastic case it's a start cap limited duty cycle, if it's got a metal case it's a run cap 100% duty cycle. Only the run caps make good crossover (Or AC coupling) caps although their size limits their applications mainly to speakers although I do have a circuit similar to this one by Dallas Lankford only using coil values (Crossover coils oversized that I took windings off of until I reach the desired inductance) tweaked to work with available start cap values. Mine will work on any amp up to 50 watts, you just plug it into a Speaker Out and then plug an external speaker into the filter.
        >
        > Elliptic Low Pass Audio Filters (Used to counter fading distortion on AM)
        > http://www.kongsfjord.no/dl/Audio/ELPAFs.pdf
        >
        > JR
        >
      • Ray Phillips
        Is it possible that you are confusing MHZ (millions of cycles per second) with KHz (thousands of cycles per second)? If you are trying to build a loop to
        Message 3 of 14 , Apr 1, 2011
          Is it possible that you are confusing MHZ (millions of cycles per second) with KHz (thousands of cycles per second)? If you are trying to build a loop to receive MHz transmissions but plugging KHz figures into formulas, then your calculations will be wildly inaccurate.

          As frequencies fall below 500KHz (0.5MHz) the amount of man-made signals reduce. At 1KHz I would expect all signals to be either natural or man-made noise rather than coherent signals. At 1KHz I, personally, would be using audio techniques not radio techniques. At 1MHz, however, I would definitely use radio techniques such as a loop and capacitor.

          Don't give up. Let the forum know what signals you are looking for and I am sure you will get help aplenty. If you are definitely looking for VLF signals then there are websites devoted to that pursuit. Take a look at http://www.vlf.it/harald/strangerec.htm or http://abelian.org/vlfrx/ for starters.

          Ray, vk5ugs




          To: loopantennas@yahoogroups.com
          From: mowypt@...
          Date: Fri, 1 Apr 2011 13:25:46 +0000
          Subject: [loopantennas] Re: What type of capacitor is used for loop antenna?




























          Thanks for your reply. Yes, I figured that I need more coil. I don't know, I read somewhere "just add more capacitance" but obviously that only works to a point.



          --- In loopantennas@yahoogroups.com, "longjohn119" <some_oil_with_your_teaparty@...> wrote:

          >

          >

          >

          >

          >

          > --- In loopantennas@yahoogroups.com, "mowypt" <mowypt@> wrote:

          > >

          > > With the loop I have, 6uf is what I need for below 1KHz and I don't know enough about capacitors. The one I have I guess it's called a "run" capacitor. It says 6uf 450 volts AC. I assume I need a different type of capacitor. Well thanks for your replies.

          > >

          >

          > You need a loop with more windings/inductance not a big cap. Having a way to measure the actual inductance is very helpful also ....

          >

          > Those run caps do make excellent bipolar caps in speaker crossovers (The + and - marks are for phasing not DC polarity), especially for high power sound reinforcement speakers .... Otherwise not much use for them other than AC motors, if it's got a plastic case it's a start cap limited duty cycle, if it's got a metal case it's a run cap 100% duty cycle. Only the run caps make good crossover (Or AC coupling) caps although their size limits their applications mainly to speakers although I do have a circuit similar to this one by Dallas Lankford only using coil values (Crossover coils oversized that I took windings off of until I reach the desired inductance) tweaked to work with available start cap values. Mine will work on any amp up to 50 watts, you just plug it into a Speaker Out and then plug an external speaker into the filter.

          >

          > Elliptic Low Pass Audio Filters (Used to counter fading distortion on AM)

          > http://www.kongsfjord.no/dl/Audio/ELPAFs.pdf

          >

          > JR

          >


















          [Non-text portions of this message have been removed]
        • Jerry Flanders
          ... You can actually see an earth resonance signal? What causes it? What changes did you see in it - freq? Jerry W4UK
          Message 4 of 14 , Apr 2, 2011
            At 10:08 PM 4/2/2011, you wrote:
            >I did some work with VLF/ELF years ago, 60KHz and down to 6.8 Hz.
            ><SNIP> 6.8Hz is the resonance of the Earth's
            >magnetic field, vertical with a capacitance hat, or a big loop laying on
            >the ground with low noise audio/instrumentation optimized op-amps with
            >filtering/amplification and you can watch it on a scope but it takes
            >DAYS to see changes in signal.

            You can actually see an "earth resonance" signal?

            What causes it?

            What changes did you see in it - freq?

            Jerry W4UK
          • Tim Hills
            I did some work with VLF/ELF years ago, 60KHz and down to 6.8 Hz. What I found was that below about 20KHz forget about tuned loops. They can be built but to
            Message 5 of 14 , Apr 2, 2011
              I did some work with VLF/ELF years ago, 60KHz and down to 6.8 Hz. What I
              found was that below about 20KHz forget about tuned loops. They can be
              built but to get any directional gain they would have to be huge and
              heavy. The more wire used the larger the gauge needed to gain any
              benefit from it. Look up the resistance/Q formulas. Very large
              capacitors (Relative to RF) and electrolytics don't work very well
              either because of the low EMF involved. The best results I got were with
              Tantalum Caps. with a 3V
              bias applied.

              Other than man-made noise there really isn't much in the 1KHz range
              other than produced by thunderstorms and Solar flares. From 70 to 200 HZ
              there's submarine coms. with very slow CW or FSK 5 letter groups, my
              main interest at the time. 6.8Hz is the resonance of the Earth's
              magnetic field, vertical with a capacitance hat, or a big loop laying on
              the ground with low noise audio/instrumentation optimized op-amps with
              filtering/amplification and you can watch it on a scope but it takes
              DAYS to see changes in signal.

              Then again you could mix the 1KHz signal with a 13KHz then use WinRad......

              That Grumpy Old Man..

              On 4/1/2011 19:41, Ray Phillips wrote:
              > Is it possible that you are confusing MHZ (millions of cycles per second) with KHz (thousands of cycles per second)? If you are trying to build a loop to receive MHz transmissions but plugging KHz figures into formulas, then your calculations will be wildly inaccurate.
              >
              > As frequencies fall below 500KHz (0.5MHz) the amount of man-made signals reduce. At 1KHz I would expect all signals to be either natural or man-made noise rather than coherent signals. At 1KHz I, personally, would be using audio techniques not radio techniques. At 1MHz, however, I would definitely use radio techniques such as a loop and capacitor.
              >
              > Don't give up. Let the forum know what signals you are looking for and I am sure you will get help aplenty. If you are definitely looking for VLF signals then there are websites devoted to that pursuit. Take a look at http://www.vlf.it/harald/strangerec.htm or http://abelian.org/vlfrx/ for starters.
              >
              > Ray, vk5ugs
              >
              >
              >
              >
            • Jerry Flanders
              Cool! I had not heard of this, and found the paper very interesting. Thanks for sharing the link. Jerry W4UK
              Message 6 of 14 , Apr 2, 2011
                Cool! I had not heard of this, and found the paper very interesting.

                Thanks for sharing the link.

                Jerry W4UK

                At 11:06 PM 4/3/2011, you wrote:

                >Yes, there is a weak signal at 7.83 Hz that's caused by the resonance of
                >the Earth's magnetic field. It's been a while since I've done any
                >reading on it but if I recall it's thought to be powered by the Solar
                >Wind. Some New-Age types refer to it as "Gaia's Heartbeat" and I recall
                >seeing portable recievers marketed to the "Earth Change" people in the
                >1990s. I see the 2012 true believers have decided to adopt it as a sign
                >now too, not to mention the Zero point energy protagonists.
                >
                >I misremembered the exact frequency, I thought it was 6.8 so I looked it
                >up. Hey, after 20+ years a 1Hz drift isn't bad for an old analog unit
                >like myself ;) It's called the "Schumann Resonance" if you want to read
                >up on it on the WWW. Note that most of the search results point to what
                >I consider Kook-n-Quack sites. PDF from Scientific source
                ><http://www.hese-project.org/hese-uk/en/papers/schlegel_schumann.pdf> is
                >the best I found on a quick search.
                >
                >Submarine coms use multiples of that resonance, I think the FSK I picked
                >up was the 11th and 13th harmonics. Kinda like coupling to a spherical
                >resonance cavity at odd multiples
                >
                >I wasn't paying much attention to any frequency shift but the amplitude
                >varied over about a 2:1 range over a 2 or 3 month period. Never looked
                >into it as far as being affected by Solar storms or flux density. It's
                >not something I spent a lot of time on, just wanted to see if I could
                >pick up EMF at that low a frequency, there was no attempt made at
                >calibration and things like dew on the ground may have affected my
                >measurements.
                >
                >I recall seeing something about local disturbances in the signal right
                >before earthquakes and the harmonics used for lightning detection, there
                >may be other applications.
                >
                >On 4/2/2011 20:19, Jerry Flanders wrote:
                > >
                > > At 10:08 PM 4/2/2011, you wrote:
                > > >I did some work with VLF/ELF years ago, 60KHz and down to 6.8 Hz.
                > > ><SNIP> 6.8Hz is the resonance of the Earth's
                > > >magnetic field, vertical with a capacitance hat, or a big loop laying on
                > > >the ground with low noise audio/instrumentation optimized op-amps with
                > > >filtering/amplification and you can watch it on a scope but it takes
                > > >DAYS to see changes in signal.
                > >
                > > You can actually see an "earth resonance" signal?
                > >
                > > What causes it?
                > >
                > > What changes did you see in it - freq?
                > >
                > > Jerry W4UK
                > >
                >
                >
                >
                >[Non-text portions of this message have been removed]
                >
                >
                >
                >------------------------------------
                >
                >If you've got links, post them in the Links section!
                >http://groups.yahoo.com/group/loopantennas/links
                >
                >Post files here. If the file comes from a website, please put it in
                >the Links rather than uploading the file.
                >http://groups.yahoo.com/group/loopantennas/files
                >
                >You can now view images at higher resolution in Photos. Upload JPG
                >and GIF into Photos. Please convert BMP or TIF to JPG or GIF before uploading.
                >http://ph.groups.yahoo.com/group/loopantennas/photos
                >
                >And please trim all this when replying!Yahoo! Groups Links
                >
                >
                >
              • Steve, g4vbd
                Hi Jerry there is also a Yahoo group for ELF and ULF who talk obout the Schumann, take a look at http://tech.groups.yahoo.com/group/ulfelf/ There are plenty of
                Message 7 of 14 , Apr 3, 2011
                  Hi Jerry
                  there is also a Yahoo group for ELF and ULF who talk obout the Schumann,
                  take a look at

                  http://tech.groups.yahoo.com/group/ulfelf/
                  There are plenty of papers, designs and results here

                  regards
                  Steve, g4vbd


                  On Sun, Apr 3, 2011 at 4:35 AM, Jerry Flanders <jeflanders@...>wrote:

                  >
                  >
                  > Cool! I had not heard of this, and found the paper very interesting.
                  >
                  > Thanks for sharing the link.
                  >
                  > Jerry W4UK
                  >
                  >
                  > At 11:06 PM 4/3/2011, you wrote:
                  >
                  > >Yes, there is a weak signal at 7.83 Hz that's caused by the resonance of
                  > >the Earth's magnetic field. It's been a while since I've done any
                  > >reading on it but if I recall it's thought to be powered by the Solar
                  > >Wind. Some New-Age types refer to it as "Gaia's Heartbeat" and I recall
                  > >seeing portable recievers marketed to the "Earth Change" people in the
                  > >1990s. I see the 2012 true believers have decided to adopt it as a sign
                  > >now too, not to mention the Zero point energy protagonists.
                  > >
                  > >I misremembered the exact frequency, I thought it was 6.8 so I looked it
                  > >up. Hey, after 20+ years a 1Hz drift isn't bad for an old analog unit
                  > >like myself ;) It's called the "Schumann Resonance" if you want to read
                  > >up on it on the WWW. Note that most of the search results point to what
                  > >I consider Kook-n-Quack sites. PDF from Scientific source
                  > ><http://www.hese-project.org/hese-uk/en/papers/schlegel_schumann.pdf> is
                  > >the best I found on a quick search.
                  > >
                  > >Submarine coms use multiples of that resonance, I think the FSK I picked
                  > >up was the 11th and 13th harmonics. Kinda like coupling to a spherical
                  > >resonance cavity at odd multiples
                  > >
                  > >I wasn't paying much attention to any frequency shift but the amplitude
                  > >varied over about a 2:1 range over a 2 or 3 month period. Never looked
                  > >into it as far as being affected by Solar storms or flux density. It's
                  > >not something I spent a lot of time on, just wanted to see if I could
                  > >pick up EMF at that low a frequency, there was no attempt made at
                  > >calibration and things like dew on the ground may have affected my
                  > >measurements.
                  > >
                  > >I recall seeing something about local disturbances in the signal right
                  > >before earthquakes and the harmonics used for lightning detection, there
                  > >may be other applications.
                  > >
                  > >On 4/2/2011 20:19, Jerry Flanders wrote:
                  > > >
                  > > > At 10:08 PM 4/2/2011, you wrote:
                  > > > >I did some work with VLF/ELF years ago, 60KHz and down to 6.8 Hz.
                  > > > ><SNIP> 6.8Hz is the resonance of the Earth's
                  > > > >magnetic field, vertical with a capacitance hat, or a big loop laying
                  > on
                  > > > >the ground with low noise audio/instrumentation optimized op-amps with
                  > > > >filtering/amplification and you can watch it on a scope but it takes
                  > > > >DAYS to see changes in signal.
                  > > >
                  > > > You can actually see an "earth resonance" signal?
                  > > >
                  > > > What causes it?
                  > > >
                  > > > What changes did you see in it - freq?
                  > > >
                  > > > Jerry W4UK
                  > > >
                  > >
                  > >
                  > >
                  > >[Non-text portions of this message have been removed]
                  > >
                  > >
                  > >
                  > >------------------------------------
                  >
                  > >
                  > >If you've got links, post them in the Links section!
                  > >http://groups.yahoo.com/group/loopantennas/links
                  > >
                  > >Post files here. If the file comes from a website, please put it in
                  > >the Links rather than uploading the file.
                  > >http://groups.yahoo.com/group/loopantennas/files
                  > >
                  > >You can now view images at higher resolution in Photos. Upload JPG
                  > >and GIF into Photos. Please convert BMP or TIF to JPG or GIF before
                  > uploading.
                  > >http://ph.groups.yahoo.com/group/loopantennas/photos
                  > >
                  > >And please trim all this when replying!Yahoo! Groups Links
                  > >
                  > >
                  > >
                  >
                  >
                  >


                  [Non-text portions of this message have been removed]
                • Tim Hills
                  Yes, there is a weak signal at 7.83 Hz that s caused by the resonance of the Earth s magnetic field. It s been a while since I ve done any reading on it but if
                  Message 8 of 14 , Apr 3, 2011
                    Yes, there is a weak signal at 7.83 Hz that's caused by the resonance of
                    the Earth's magnetic field. It's been a while since I've done any
                    reading on it but if I recall it's thought to be powered by the Solar
                    Wind. Some New-Age types refer to it as "Gaia's Heartbeat" and I recall
                    seeing portable recievers marketed to the "Earth Change" people in the
                    1990s. I see the 2012 true believers have decided to adopt it as a sign
                    now too, not to mention the Zero point energy protagonists.

                    I misremembered the exact frequency, I thought it was 6.8 so I looked it
                    up. Hey, after 20+ years a 1Hz drift isn't bad for an old analog unit
                    like myself ;) It's called the "Schumann Resonance" if you want to read
                    up on it on the WWW. Note that most of the search results point to what
                    I consider Kook-n-Quack sites. PDF from Scientific source
                    <http://www.hese-project.org/hese-uk/en/papers/schlegel_schumann.pdf> is
                    the best I found on a quick search.

                    Submarine coms use multiples of that resonance, I think the FSK I picked
                    up was the 11th and 13th harmonics. Kinda like coupling to a spherical
                    resonance cavity at odd multiples

                    I wasn't paying much attention to any frequency shift but the amplitude
                    varied over about a 2:1 range over a 2 or 3 month period. Never looked
                    into it as far as being affected by Solar storms or flux density. It's
                    not something I spent a lot of time on, just wanted to see if I could
                    pick up EMF at that low a frequency, there was no attempt made at
                    calibration and things like dew on the ground may have affected my
                    measurements.

                    I recall seeing something about local disturbances in the signal right
                    before earthquakes and the harmonics used for lightning detection, there
                    may be other applications.

                    On 4/2/2011 20:19, Jerry Flanders wrote:
                    >
                    > At 10:08 PM 4/2/2011, you wrote:
                    > >I did some work with VLF/ELF years ago, 60KHz and down to 6.8 Hz.
                    > ><SNIP> 6.8Hz is the resonance of the Earth's
                    > >magnetic field, vertical with a capacitance hat, or a big loop laying on
                    > >the ground with low noise audio/instrumentation optimized op-amps with
                    > >filtering/amplification and you can watch it on a scope but it takes
                    > >DAYS to see changes in signal.
                    >
                    > You can actually see an "earth resonance" signal?
                    >
                    > What causes it?
                    >
                    > What changes did you see in it - freq?
                    >
                    > Jerry W4UK
                    >



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