I'll also add in my recommendation to build. For 2018 Field Day, I built a Kent Britain WA5JVB 1296 MHz Cheap Yagi. The plans can be found in the PDF document https://www.wa5vjb.com/yagi-pdf/cheapyagi.pdf.%C2%A0 It was easy to construct, if you are careful. Without tuning, I was able to get a 1.25 SWR on transmit frequency for AO-92 in L/v mode. I was able to make two successful QSOs during the one decent pass, for my location on Field Day that AO-92 was in L/v mode. Unfortunately, that pass occurred before Field Day officially started. Anyway, I felt validated that the antenna worked! Give it a try!
73,
Mac Cody / AE5PH
On 08/27/2018 05:19 PM, Greg D wrote:
Add in my recommendation for building your own. I made one with some old aluminum Radio Shack "ground wire" that I had laying around. Follow the calculator for radius and spacing as best you can, but don't sweat over the super fine detail. Helix antennas are inherently forgiving in construction, and are nice that they are circularly polarized which helps when working a spinning satellite. Both traits are in contrast to building a Yagi beam.
Anything inside the helix is invisible to the antenna; I used an aluminum rod, and heavy zip ties out to the wire turns. Tie one end around the central support, then use another (smaller one) to attach the wire to the "tail" of the first. Don't need to support every turn; just use enough to keep things kind of in place.
Greg KO6TH
Zach Metzinger wrote:
On 8/27/18 2:28 PM, Philip Jenkins wrote:
Does anyone have recommendations for another brand, or have an appropriate one for sale? (I wish I had bought some of those loop yagis which were prominently displayed in Ball Arena at Hamvention in the early 90s...)
You might also try this home-brew model:
https://www.mictronics.de/2011/07/1240mhz1280mhz-diy-helix-antenna/
--- Zach N0ZGO _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb