RE: [amsat-bb] Echo totally unuesable on an Arrow

["Howard Long" <howard@xxxxxxxxxxxxxx>]

Hi Emily, Keith

I've been trying AO-51 since the first open pass over Europe only with a
TH-D7 and an Arrow, and only made it in today for two QSO's. I've always
been able to hear it fine. As a fairly seasoned TH-D7/Arrow operator, I
assumed something was wrong with my hardware or configuration. At first I
thought I'd got the wrong uplink, then I thought I'd got the wrong PL tone,
then I thought my radio's PA was dead, then I thought the 2m side of the
Arrow was broken.

In the end I had everything set up fine - except (a) everyone else was
running 1kW+ erp, (b) the passes I chose were perhaps rather busy passes.

The problem with the way the PL tone access works on AO-51 is that as soon
as there is heterodyning on the uplink, the tone squelch seems to close
leading to carrier with no modulation on the downlink. Therefore everyone
assumes it's open to transmit.

As a direct comparison, on SO-50, you still get to hear the heterodyning,
and inevitably folks drop carrier on the uplink as they realise they're
being trampled on. But at least you can tell something's happening, and I
believe that op's hearing the heterodyning in itself provides some degree of
protocol. This is a subtle difference in the way AO-51 and SO-50 operate.

The way it works at the moment encourages operators to simply continuously
key up and talk until they hear their own downlink, which only makes it
worse.

Hopefully the initial hiatus on AO-51 will drop and QRP ops will stand a
better chance. Whether there will be another knack to crack this bird under
busy conditions remains to be seen.

73, Howard SM/G6LVB
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