[amsat-bb] Modulation levels on AO-85

Matthew Stevens matthew at mrstevens.net
Tue Aug 15 03:10:09 UTC 2017

I'm not entirely sure what you're talking about. There's a big difference between not fully capturing the repeater due to low power or mismatched polarity, and having low audio.

I've heard many stations who were fully capturing the repeater (no noise on their signal) yet were barely copyable because it sounded like they were holding the mic 10 feet from their mouth. On the other hand, I've also heard lots of stations with less than perfect, scratchy signals who had fine modulation and were plenty loud.

As Jerry Buxton said earlier in this thread...If you've got a quiet signal, the first place I would look is your mic and mic settings.

- Matthew nj4y

> On Aug 14, 2017, at 22:47, Tom Schuessler <tjschuessler at verizon.net> wrote:
> The issue with quieting vs. Modulation level is that if a station has enough
> power to do full quieting FM into the AO-85 bent pipe, than even if he is a
> weak talker, or his radio has low modulation gain, he will be heard because
> the background noise is minimal.   Having enough power to get to that point
> is a good thing, but there are many stations, like myself sometimes, that
> are using HTs for uplink and downlink.  5 watts, not the right transmit
> polarization and a slightly deaf RX on AO-85 due to an antenna not quite
> what it should've been (Documented shortly after AO-85 launch) and you have
> a number of things lined up against you.   This presents a situation where
> this combination results with a station barely coming through the noise and
> thus being hard to hear.  Again remember that AO-85 is a bent pipe after it
> is tuned on via hearing a station transmitting a 67 Hz tone so that is why
> you can hear FM noise through it when no RX of uplink signal is present.  It
> has no squelch to prevent weak signals from getting through.  
> I have a little Chinese radio that definitely even on "Wide" mode, is
> quieter than another radio I own.  Most HT's give no option to adjust this
> value.  Yelling into these radios does not help as they seem to have some
> level of high signal limiting or compression, as simple as plane old peak
> clipping.  I know that Yaesu does allow for mic gain adjustments on some of
> their Fusion radios but most FM only handhelds have no option for fine
> tuning.
> My suggestion to little pistols like myself (When learning to work FM
> satellites like AO-85), is to just not try during a busy pass but wait for a
> lesser trafficked pass so you can learn how best to manipulate your
> transmitting circumstances to hear yourself and be heard.  
> Jerry Buxton, the Fox series daddy, assures us that the newer iterations of
> the AMSAT Fox birds will have a little better ears and hopefully that will
> help immensely.  
> Have patience with the little guys.  You probably were one once yourself.
> Tom Schuessler
> n5hyp at arrl.net
> ------------------------------
> Message: 3
> Date: Mon, 14 Aug 2017 19:27:29 +0200 (CEST)
> From: jerry.tuyls at telenet.be
> To: amsat-bb <amsat-bb at amsat.org>
> Subject: Re: [amsat-bb] Modulation levels on AO-85
> Message-ID:
>    <1165542169.90891698.1502731649191.JavaMail.zimbra at telenet.be>
> Content-Type: text/plain; charset=utf-8
> Spending some time here by telling several times on AO-85 passes about bad
> modulation to the same stations, but they DON'T listen.
> Just ignoring them, because i cannot understand them on my TS-790/FT-847.No
> narrow FM and no PL tone. Never got a problem.
> And please...why do some stations upload logs with DWNlink freq on sat qso's
> instead of the UPlink freq?
> Always having some rejected qsl's because qso's don't match due to wrong
> band. I log with VQlog, uplink and dwnlink freq etc, so i think the TX-freq
> is most important for logging sat'qso's and not the RX-freq? 
> 73's
> Jerry,ON4CJQ
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