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Nashville bombing spotlights vulnerable voice, data networks
I strongly support the idea of a regular NVIS net. Maybe immediately after the club net each Thursday night on 75 meters. I would be happy to help with suggestions for antennas to meet various member'
I strongly support the idea of a regular NVIS net. Maybe immediately after the club net each Thursday night on 75 meters. I would be happy to help with suggestions for antennas to meet various member'
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Jef - N5JEF
· #6946
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Links for End Fed Antenna Design / Testing and Ugly Balun Chokes
Brian - I think all of the antennas were verified with excellent to usable SWR on 40, 20, 15 meters, but slightly over 2:1 on 10 meters. I wasn't directly present for the testing of the first one, but
Brian - I think all of the antennas were verified with excellent to usable SWR on 40, 20, 15 meters, but slightly over 2:1 on 10 meters. I wasn't directly present for the testing of the first one, but
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Jef - N5JEF
· #6788
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Nice. Thanks for the update! - Jef
Nice. Thanks for the update! - Jef
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Jef - N5JEF
· #6752
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Joshua— This is what I would recommend trying, quick and easy, and see how it works at 50ft up.
Joshua— This is what I would recommend trying, quick and easy, and see how it works at 50ft up.
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Jef - N5JEF
· #6734
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Oh, and if you go with a ¼λ ground plane suspended a tall tree, you can bend the radials away from the monopole to about 30-45° beyond orthogonal to get the impedance up from 36Ω to about 50Ω. - Jef
Oh, and if you go with a ¼λ ground plane suspended a tall tree, you can bend the radials away from the monopole to about 30-45° beyond orthogonal to get the impedance up from 36Ω to about 50Ω. - Jef
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Jef - N5JEF
· #6733
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Joshua — A half-wave dipole suspended from a branch in a pine tree about 50 ft above ground level could work well. However… You would want to bring the center-fed feed line out perpendicular to the an
Joshua — A half-wave dipole suspended from a branch in a pine tree about 50 ft above ground level could work well. However… You would want to bring the center-fed feed line out perpendicular to the an
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Jef - N5JEF
· #6732
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Joshua -- You can certainly make a dipole using two half-wave elements instead of the usual two quarter-wave elements. Then the gain will be nearly 3dB greater. The problem would be how to feed it, be
Joshua -- You can certainly make a dipole using two half-wave elements instead of the usual two quarter-wave elements. Then the gain will be nearly 3dB greater. The problem would be how to feed it, be
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By
Jef - N5JEF
· #6731
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NVIS and Happy Hour Propagation with Ben Witvliet PE5B
Forwarding this link (below) to a 20-minute video because NVIS, and because the presenter, Dr. Ben Witvliet, is probably the best researcher on NVIS that I know of. - Jef ---------- Forwarded message
Forwarding this link (below) to a 20-minute video because NVIS, and because the presenter, Dr. Ben Witvliet, is probably the best researcher on NVIS that I know of. - Jef ---------- Forwarded message
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By
Jef - N5JEF
· #6720
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Okay, I suppose you mean Sierra Hotel India Tango, but whatever... Congrats on the General. Now you can build some seriously big antennas. :-) - Jef
Okay, I suppose you mean Sierra Hotel India Tango, but whatever... Congrats on the General. Now you can build some seriously big antennas. :-) - Jef
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Jef - N5JEF
· #6719
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
10 tight winds around the boom, non-overlapping, should make a good choke for this band. - Jef
10 tight winds around the boom, non-overlapping, should make a good choke for this band. - Jef
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Jef - N5JEF
· #6715
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Joshua - Very nice to see someone putting this kind of effort into antenna building (and experimenting.) You could probably make a neater, and somewhat more effective choke if you coiled the coax tigh
Joshua - Very nice to see someone putting this kind of effort into antenna building (and experimenting.) You could probably make a neater, and somewhat more effective choke if you coiled the coax tigh
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By
Jef - N5JEF
· #6712
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Edited
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Oh, and it's a good idea to form a choke at the feedpoint with several turns of coax tightly wrapped together around the boom, to reduce the inevitable common-mode current you'll get due to feeding a
Oh, and it's a good idea to form a choke at the feedpoint with several turns of coax tightly wrapped together around the boom, to reduce the inevitable common-mode current you'll get due to feeding a
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Jef - N5JEF
· #6710
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Edited
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Greg - At work so gotta keep this brief. The hairpin, or beta match, has some advantages in this application—mainly that it is symmetrical so it doesn't distort the pattern as a gamma match would at t
Greg - At work so gotta keep this brief. The hairpin, or beta match, has some advantages in this application—mainly that it is symmetrical so it doesn't distort the pattern as a gamma match would at t
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By
Jef - N5JEF
· #6709
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Edited
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Here's a closeup of the hairpin match on the one I built:
Here's a closeup of the hairpin match on the one I built:
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Jef - N5JEF
· #6706
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Edited
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Joshua - Back in January 2015 we held an antenna-building party at my place and six of us built "tape measure" 3-element Yagis for 2 meters. Quick and easy to make, and the flexible elements fold up f
Joshua - Back in January 2015 we held an antenna-building party at my place and six of us built "tape measure" 3-element Yagis for 2 meters. Quick and easy to make, and the flexible elements fold up f
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By
Jef - N5JEF
· #6705
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Three Element Yagi / Beam built with gifted/salvaged parts.
#antennas
Joshua - Nice work. Keep in mind that the length of the driven elements (plural) should each be a quarter wave at the geometric mean of the frequency range of interest. It's not the tip to tip length
Joshua - Nice work. Keep in mind that the length of the driven elements (plural) should each be a quarter wave at the geometric mean of the frequency range of interest. It's not the tip to tip length
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By
Jef - N5JEF
· #6703
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Using a CB Antenna with an SDR receiver #antennas #elmer #howto
#antennas
#elmer
#howto
Doug - Nice work, and makes sense too! Thanks for sharing this. - Jef N5JEF
Doug - Nice work, and makes sense too! Thanks for sharing this. - Jef N5JEF
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Jef - N5JEF
· #6697
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Using a CB Antenna with an SDR receiver #antennas #elmer #howto
#antennas
#elmer
#howto
On Tue, Oct 20, 2020 at 6:05 AM Jef - N5JEF via groups.io <jef@...> wrote: Here's a picture of my 10-ft diameter loop for 40-60-80 meters, a work in progress. Here's the flanges
On Tue, Oct 20, 2020 at 6:05 AM Jef - N5JEF via groups.io <jef@...> wrote: Here's a picture of my 10-ft diameter loop for 40-60-80 meters, a work in progress. Here's the flanges
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Jef - N5JEF
· #6674
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Edited
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Using a CB Antenna with an SDR receiver #antennas #elmer #howto
#antennas
#elmer
#howto
Here's a picture of my 10-ft diameter loop for 40-60-80 meters, a work in progress.
Here's a picture of my 10-ft diameter loop for 40-60-80 meters, a work in progress.
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By
Jef - N5JEF
· #6671
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Edited
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Using a CB Antenna with an SDR receiver #antennas #elmer #howto
#antennas
#elmer
#howto
The small transmitting loop, often described misleadingly as the "magnetic loop" antenna, with a circumference under ⅓ wavelength (in some applications, under ⅒ wavelength) is a practical example of a
The small transmitting loop, often described misleadingly as the "magnetic loop" antenna, with a circumference under ⅓ wavelength (in some applications, under ⅒ wavelength) is a practical example of a
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By
Jef - N5JEF
· #6665
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