[amsat-bb] Re: Working SO-50

Eric Knaps, ON4HF on4hf at telenet.be
Sun Dec 4 04:25:12 PST 2011

Hello Ib,

I agree with you.
This is what I have in my Doppler.sqf file for SatPC32:


and in my SubTone.sqf:


This is for the Yaesu FT-847.


Amateur Radio Station ON4HF
Eric Knaps
Satellite manager UBA


Op 3/12/2011 21:45, Ib Christoffersen schreef:
> Working SO-50.
> I think it is time to look at how one can operate over SO-50 and the
> problems that can be encountered.
> First the normal and nominal data:
> Uplink is at 145.850 MHz.  Downlink at 436.795 MHz.
> If it is not ON - use 74.4 Hz CTCSS tone to activate the transmitter for 10
> seconds to have it on for nominally 10 minutes - when on use 67 Hz CTCSS
> tone during your transmission.
> That was the intended normal operation.
> Now to the deviations from the normal scheme.
> The downlink frequency sometimes jump approximately 5 kHz. Therefore I have
> two different frequencies pairs to be used in SATPC32:
> SO-50,436788.50,145849,FM,FM,NOR,0,0
> SO-50,436795,145850,FM,FM,NOR,0,0
> If you do not use Full Doppler Tracking it is not much of an issue. Just
> tune for best downlink.
> Talking about SATPC32 here are the entries for the CTCSS tone:
> SO-50,67.0,$3F,1
> SO-50,74.4,$3E,3
> The first data is for the ICOM IC-910 radio. If you use another radio please
> look at the information in SATPC32.
> Next problem is the change of polarity of the downlink signal during a pass.
> The polarity changes during the pass. At least I have to switch polarity a
> few times from RHCP to LHCP to optimize the downlink signal. That has been
> confirmed by others. How it works using linearly polarized antennas I do not
> know - but I think there will be some fading.
> And if that is not enough - at least here over Europe - we have to put up
> with QRM on the uplink from a lot of different sources like repeaters and
> people using our frequencies as cheap phone connections.
> The result of the QRM is that it sometimes is difficult to turn SO-50 on.
> Also the QRM may turn the transmitter off.
> And since the inclination is not sun synchronous we have to live with a
> steady change of pass times over the year.
> Some may think I am not a fan of SO-50. That is not the case. It is a very
> good satellite we got for free and it works very well.
> Already more people are using it over Europe after AO-51 is not with us any
> more. That just took a couple of days.
> 73 OZ1MY/Ib
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