[amsat-bb] Re: AO-07 Distorted audio

[Andrew Glasbrenner]

Well stated Paul!

Additionally, I fear some users just turn up the power to overcome a poor receive system.

73, Drew KO4MA

Sent from my iPhone

> On Apr 25, 2014, at 8:23 PM, Paul Stoetzer <n8hm at arrl.net> wrote:
> 
> Absolutely!
> 
> The recommendation at the time of launch was to limit power output to no
> more than 100W ERP (which is about 25 watts to a small antenna like an Elk
> or an Arrow). This is even more critical now since the solar panels are
> almost certainly not supplying enough power to drive the transmitter to
> it's full power output. At certain times of the year, there are poor solar
> angles on the panels too, which reduces power availability. Remember too
> that AO-7 will enter a period where it eclipses on every orbit over the
> south pole within the next week or so. That period will last for about 9
> weeks. It should be in Mode B every day as a result, but from what I've
> read about past eclipse cycles, it can act a bit odd during that time.
> 
> On too many passes, I hear distorted audio and reflections throughout the
> transponder from it being hit too hard with SSB and especially CW. CW,
> being full power at key down, unlike SSB, is even harder on a linear
> transponder.
> 
> If everyone would just have the courtesy to keep their uplink power to a
> reasonable level, AO-7 can be a very enjoyable satellite with a large
> footprint providing the best DX opportunities currently available.
> Unfortunately, this problem is not new as a glance at the AMSAT Newsletters
> from 1974-1981 shows.
> 
> I recommend the following reading: The Editorial + Letter from W4NUL/5 in
> the March 1976 AMSAT Newsletter, the AMSAT-OSCAR-7 QRP Test Telemetry
> Report in the November 1976 AMSAT Newsletter, and the June 1976 QRP Test
> Results from the December 1976 AMSAT Newsletter. All available here:
> http://www.ka9q.net/AMSAT-Newsletter-1976.pdf
> 
> Please calculate your ERP ( http://www.csgnetwork.com/antennaecalc.html )
> and keep it to no more than 100W.
> 
> 73,
> 
> Paul Stoetzer, N8HM
> Washington, DC
> 
> 
>> On Fri, Apr 25, 2014 at 11:12 AM, Dave Webb KB1PVH <kb1pvh at gmail.com> wrote:
>> 
>> Only when people are running too much power. It's called FM'ing.
>> 
>> Dave-KB1PVH
>> 
>> Sent from my Verizon Wireless Droid RAZR
>>> On Apr 25, 2014 11:10 AM, "Peter Wilson" <protest at virginmedia.com> wrote:
>>> 
>>> Just worked IK8YSS on AO-07.
>>> 
>>> 
>>> 
>>> Haven't worked this satellite for a while and whilst I know the bird is
>>> very
>>> old, the audio on this pass was very distorted.
>>> 
>>> 
>>> 
>>> Is this common?
>>> 
>>> 
>>> 
>>> Peter
>>> 
>>> G8KEK
>>> 
>>> _______________________________________________
>>> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
>>> Not an AMSAT-NA member? Join now to support the amateur satellite
>> program!
>>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>> _______________________________________________
>> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
>> Not an AMSAT-NA member? Join now to support the amateur satellite program!
>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb