[amsat-bb] Noise, distortion and fading on AO-92 L/v downlink

[Jean Marc Momple]

Ron,

There was an exchange about this issue about same earlier this year.

My observation (from memory) and comments where as follows:

1) That the fading is on the L uplink, easy to tests: You just monitor the S/N with Foxtelem while listening to yourself on the downlink and you will notice that the fading occurs on your voice only.
2) The L-band is much more affected by the surrounding such as trees, building etc. than UHF or VHF.
3) Having too much power also does not help as if near a water plan or iron sheet roof nearby may create multi-path fading to the bird in spite of the distance. Keep the power low as in any case not much required (depending on the antenna gain).

Hope this help.

I wish all on the BB a Merry-Xmas and the best for 2019 (seems a promising one with the number of birds being sent up-there & Es’Hail 2, Hi!).

73



Jean Marc (3B8DU)




> On Dec 24, 2018, at 6:55 PM, Ronald G. Parsons <w5rkn at w5rkn.com> wrote:
> 
> To my ear, the L/v downlink just “sounds” more distorted and noisier than the U/v downlink. Perhaps something is coming in the L port or is internally generated. The downlink path in my radio is identical in L/v and U/v. The rapid fading last weekend was very noticeable at lower elevations and was close to a 30 sec period. At higher elevations, it was not noticeable. I’ll try to remember to screen capture the downlink waterfall next weekend.
> Ron W5RKN
> 
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