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Re: My theory on ISS packet reception !!



VK5ZAI started a topic on ISS performance.  Here are my thoughts:

Now that we have seen stations on Hawaii and South Africa, we could ask
them to put up a 30 second test beacon and routinely record hits from ISS.
These continuing statistics would be the best evaluator of overall ISS
performance.  They could start at say 10W ERP into an omni.  Then adjust
for a power level that gives them an average 90% on high passes.  Thus
they can find the minimum threshold.  The Hawaii station would be the best
source of data, since there is noone else within 2000 miles.  The South
Africa station has few hams in that range, but there may be interlopers on
the uplink that would confuse results...

A Fixed test signal on center freq to a vertical WHIP antenna adjusted for
90% hits on high passes would then also show the statistical success of
low passes and or the beginning and ending high doppler...

de WB4APR, bob

On Sun, 27 May 2001, VK5ZAI wrote:

> My thoughts on the ISS. 2m. RX.
> I like many others never had a problem with packet
> on Mir even when I was running 5 watts up.
> I can get into the ISS. TNC but find it requires
> between 25 - 75 watts.
> Being one of the ISS telebridge stations I have
> done quite a number of family contacts for this
> crew and also the last crew and on all occasions I
> have found that they have trouble at AOS and LOS
> receiving me, but I find their signal is still
> quite readable. They are running a max of 5 watts
> (I think)  and  I am running up to 75 watts into a
> 10 turn helix.
> I don't think the problem is terrestrial QRM
> 'cause these contacts are done on an undisclosed
> frq. and we have very little traffic down here in
> Australia.  We do have a lot of QRM from the
> Islands north of us on 2m. which can be heard on
> AO-14 when it is a northern pass, however I am
> referring to ISS passes that are well south of
> these problem areas.
> My theory is that either their RX is a little on
> the deaf  side or there is something running on
> board the ISS that is de-sensing their rig. By
> this I am not ruling out that the TNC has problems
> as well.
> Let's hear your ideas on this.
> --
>        73 de Tony. VK5ZAI.
> 
>   Aust. ARISS Co-ordinator
> 
>   J.A.(Tony) Hutchison.
>   P.O. Box 216
>   PARINGA. SA. 5340.
>   Australia.
>   _____________________________
>   Grid.QF05jt: AMSAT Aust..#799
>   Member of AMSAT-NA....#33418
> 
> 
>   WEB SITE: http://www.electric-web.org
> 
>   Riverland Radio Clubs web site:
> http://www.rrc.org.au
> 
> 
> 
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de WB4APR@amsat.org, Bob

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