Re: [amsat-bb] AO-40 Transponder Question

[Andrew Glasbrenner <glasbrenner@xxxxxxxxxxxxxx>]

>2. Use a small dish for 2401 Mhz downlink and a small yagi for 435 MHz uplink.  My AO40 portable setup uses a >2-foot dish for the 2401 downlink and a 7x7 yagi for the 435 MHz uplink.  I'll send you a photo in a separate >email.  KO4MA has done successful portable operation with an 18-inch DSS dish.  Most people think reception is >inadequate with such a small dish, though.

As do I. The 18" dish was a neccesity based on what I could assemble in 3 days before the trip, and fit in my luggage. I had difficulty at times hearing, as a few stations will atest, however, I had 2 things working in my favor. AO-40 was either coming into or out of (I forget now which) an off pointing period and the range and squint combo was quite low and very favorable. Second, I used a DEM preamp which was an incredible help with the 18" DSS dish. At that size everything had better be perfect in order to hear decently on SSB. I know several guys use the 18" dish...these you can normally tell by how loud they have to be to hear themselves. Bigger is certainly better unless you have to stuff it in a suitcase.

I certainly should have mentioned this earlier... www.g6lvb.com has several excellent articles and pictures of Howard's "brolly" dishes (umbrella for us Americans). Howard's have been all over including 3A and Dayton hamvention that I know of.

73, Drew KO4MA




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