[amsat-bb] Re: AO-51 mode change and recommendation

[Luc Leblanc]

On 28 Dec 2009 at 19:13, Andrew Glasbrenner wrote:

Date sent:      	Mon, 28 Dec 2009 19:13:24 -0500
From:           	Andrew Glasbrenner <glasbrenner at mindspring.com>
Subject:        	[amsat-bb]  AO-51 mode change and recommendation
To:             	Amsat-BB <amsat-bb at amsat.org>

> AO-51 has been switched to the SSB/FM crossmode repeater, 145.880 USB 
> up, 435.150 FM down. Power output is 1.93 watts. The downlink modulation 
> is set very high, so that even very weak signals will be audible. The 
> downside to this is that someone running excessive power will cause the 
> downlink to distort.If this happens I'll be forced to adjust the 
> modulation level down, or possibly end the mode early. For a "normal" 
> station, 5 watts on the uplink to a modest gain antenna is entirely 
> sufficient. Please use the minimum power necessary. This mode -requires- 
> tuning the SSB uplink precisely for Doppler, and to effectively do that 
> you will need full duplex.
> 
> Please use this for voice communications only, until Straight Key Night, 
> when CW will be the designated mode.
> 
> Thanks, and enjoy this unusual mode.
> 
> 73, Drew KO4MA
> AMSAT-NA VP Operations
> _______________________________________________

On the first 3.9 deg morning pass i was able to hear F6BYJ and an ON station my own downlink was quite distorted even with any 
signal/modulation level.

On the second pass signal peak at S9 plus 20 but my downlink aidio was rather weak. Signal from the satellite was breaking up but i was 
able to hear my downlink with 5 watts for most of the past but as probably a commanding station was adjusting the levels the near end of 
the pass my audio became extremely weak and seems to never getting back at the AOS to TCA level.

The first morning low pass audio adjustment produce a very good and clean signal but on the second one audio appears to be muted at AOS to 
TCA and became extremely muted on the second half on the pass to a point where no communication was possible. It is not a signal problem 
but just the audio who seems to be adjusted at the right level.

No distortion has been noted too.

The only one problem i was alone for the whole pass speaking to myself...

"-"


Luc Leblanc VE2DWE
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