[amsat-bb] Re: SO-50 eludes me

Gordon JC Pearce MM3YEQ gordonjcp at gjcp.net
Fri Nov 28 01:01:21 PST 2008


francesco messineo wrote:
> Hello
> 
> 
> On 11/28/08, Mark Lunday, WD4ELG <mlunday at nc.rr.com> wrote:
>> I have worked every bird several times: AO7, AO16, AO27, AO51, FO29, VO52.
> 
> same here, plus FO-20, UO-14 and maybe some other I don't remember now...
> 
>>  But I have never worked SO50.  Tonight I had a pass DIRECTLY overhead.  I
>>  tried the standard initiation call with 74.4 CTCSS, and then calling with 67
>>  Hz.  Never heard a thing.  In fact, I don't think I have ever heard SO50.
> 
> are you working full duplex? I always found SO-50 very easy to work
> (well at least to hear myself back), the 74.4 tone must be sent for
> one or two seconds continuously then switch to 67 Hz tone. I work with

I programmed up two channels on my TH-F7E with "SO-50 74" and "SO-50 67" 
and the same carrier frequency, so I can TX with the "wake the bird up" 
tone then switch to 67 for actual QSOs.  Other radios will probably have 
this facility.

> handeld homemade dual V/U yagi usually and I noticed that this bird is
> particularly sensitive to polarization, so I need to rotate often the
> yagi to find the best signal. I didn't try recently anyway, beeing on
> other bands :-)

I have pretty much the same setup - homebrew WA5VJB "Cheap Yagi" design, 
5 ele 70cm and 3 ele 2m on the same boom with a HB9ABX diplexer.  Even 
if the polarisation is fairly badly off you should hear *something*.

>>  I triple-checked the Doppler, turned down the squelch, turned up the RF
>>  gain.  Not a peep.  Even with only my Arrow yagi fixed at 30 degrees EL, I
>>  should have heard something.  All I heard was the rush of static.  I know
>>  this bird is lower orbit and smaller power out, but I should hear something,
>>  right?
> 
> if nothing is wrong with the bird yes, you should at least hear
> yourself. Activity was low even in Europe on this bird.
> 

What I found when I was getting started with finding satellites and 
working them was it takes a bit of time to "get it", and then it's 
fairly easy.  Trying to point the antenna the right way, tune to the 
right frequency as you chase the downlink down the band, and talk into 
the radio is all a bit much at first.  It's a bit like gliding, when 
everyone else is getting thermals *except you* - and then you feel the 
little bump as the wingtip starts to roll out of a thermal, so you roll 
back against it and you're going up!  There's a sudden "ding!" moment 
where it all falls into place.

Keep trying, it's there.

Gordon


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