[amsat-bb] AO-40 Antennas - 17 Turn Helix v 24" BBQ Dish (13cm)

[Andy Glenn <andy.glenn@xxxxxxxxxxxxxxxx>]

I am currently using a 17 Turn RHCP Helix (16dB Gain - apparently) for the 13cm Downlink on AO-40 with a UEK-3000 Down Converter. I am able to work contacts reasonably well on the S1 downlink but most fade into the noise on the S2 downlink (I have taken Squint angles into account). More gain is obviously required. I have a 24"x20" BBQ Grid Dish (21dB Gain) but this is Linear Polarization - either Horizontal or Vertical. With the 3dB Hit for not being RHCP the BBQ Dish theoretically gives me a 2dB advantage over the Helix.. But, it is a lot of hassle to swap the antenna, and I'd like to know whether it's worthwhile!

Is anyone else using a 24"x20" BBQ Grid Dish (SPG-24) and if so, how does it perform on the S2 downlink? Is it better using Horizontal or Vertical Polarization - or no difference?

Thanks for any info..

Andy, M1CPM

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