[amsat-bb] Re: 144 Mhz contact made using ISS as passive reflector
kl7uw at acsalaska.net
Tue Dec 11 21:33:31 PST 2007
Already discussed on the MoonNet reflector:
Subject: Re: [Moon-net] ISS communicaton NOT a GOOD idea !!!!
Hi Steve ,
Even our "big" signals are small when they arrive up there .
Assume you use 1kw and 20dB antenna gain , this makes an ERP of 100kw or 80
dBm ERP, once your signal is +/- 600km further then you have about -130dB
less power due the path loss (on 144MHz) , this means that your signal
arrives at ISS with a level of -50dBm , so nothing to worry about .
At 07:49 PM 12/11/2007, Greg D. wrote:
>I thought of doing this back in October, when all the Sputnik-1 /
>early satellite discussion was happening. Echo-1, and all
>that. But, I would think that NASA (if not the crew) would frown on
>a bunch of folks on the ground hurling a few megawatts EIRP at their
>home in outer space. If Bob had to have a bazillion levels of
>safety in place for the little PCSAT-2 transmitter, I would think
>this would be right up there in the safety category, no?
>I haven't done the math yet... Are we far enough away that 1/x**2 saves us?
> > Date: Tue, 11 Dec 2007 11:32:50 -0800
> > From: bob at evoria.net
> > To: amsat-bb at amsat.org
> > Subject: [amsat-bb] 144 Mhz contact made using ISS as passive reflector
> > http://www.southgatearc.org/news/december2007/bouncing_signals_off_iss.htm
> > Congrats to the DF2ZC and DH7FB on making a CW contact using
> > the ISS as a passive reflector!
> > It's interesting that in the article Bernd discusses the problems
> > with using PSK due to doppler, as well as manually having to
> > set az and el. It seems to me that a couple of well equipped
> > computer-controlled earth stations should be able to do this using
> > One True Frequency principles with PSK. Wish I had the equipment
> > to give it a try.
> > Bob - AE6RV
> > _______________________________________________
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Ed - KL7UW
BP40IQ 50-MHz - 10-GHz www.kl7uw.com
144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w
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