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Re: working ISS



Francesco,

IF you are trying to work paket on 2 meters, as said below,
no Doppler correction should be needed. Doppler +-3kc on VHF.
However if trying to use the repeater (when on) the uplink frequency
is extremely critical!! You have to be within a kc or so to be able
to make it. If the repeater is busy with stations GOOD LUCK!
That is what you will need. Also you might need more power than
what you normally use. Of course this adds to the problem!
Reason, ISS is VERY POPULAR when it is in
the repeater mode. Thus there are MANY stations trying to get in.
Try to keep in mind that these HAMS "trying" to make it into ISS
are NOT satellite types. They don't even know what Doppler means.
So, there are many stations OFF FREQUENCY. This adds to the noise
floor. Saying that, basically working ISS repeater is "like"
working a DX pile-up. The strongest station WINS.

This weekend, Bill McArthur will be operating on 437.550 SIMPLEX.
You will need your Doppler here, but I bet it will be less critical
than the repeater. We will see....

Basically QRM is the problem. IF you were in Hawaii, you would
be talking to yourself.

Good luck and 73...

Scott WA6LIE




From: "Francesco Messineo"


> Hello,
> 
> On Tue, Jan 10, 2006 at 06:16:29AM -0800, MM wrote:
> > 
> > Hi Francesco:
> > 
> > If ISS is on 2meter mono band, then doppler is only
> > 3.3k max.
> > Doppler adjustment on 2meter FM is optional.
> 
> well, I have monitored several times the downlink and I feel that some
> adjustment is necessary on the frequency, at least on my radio. 
> I've never been able to get heard, I don't know if it's a QRM problem 
> (too many stations uplinking and/or too much power used) or a frequency
> problem on my side. I know that if I were the only station uplinking
> probably I could forget to adjust my TX frequency.
> 
> > 
> > If ISS is on the 440 band, then will need to adjust
> > for doppler.
> 
> sure, but in that case it's a U/V transponder, so I could hear
> myself on the downlink, as any other LEO, right?
> 
> Thanks for hints & links 
> 
> 73 de IS0FKQ
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