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Re: Use less uplink power!



Hello Achim, readers,

I only can agree! My first attempts to uplink on the sat were not really 
succesfully. I Calculated, and thought my station whould even have some 
reserves. Well... I was very poor on the sat, and I had to bay an PA, to be 
readable (for from being as strong ass all those stations - but at the level 
which is suggested --> 10dB)

But some weeks ago, At an sunday afternoon I was really surprised. I could 
hear we quite strong on the downlink, even without my PA. So I fast checked 
the beacon, and the AGC was around 5 to 7. And it worked as calculated the 
first time.

There are quite a lot of stations on the sat who appear to have not an 
adequate receiving system, and simple blast a lot of power on the uplink 
towards the sat because of this. It's difficult to convince them all to 
improve their receiving system. Sometimes I wish LEILA would act much more 
agressive hi. I have yet to be notched sout by LEILA..

73, Luc, LX2GT


On Monday 13 January 2003 17:33, Achim Vollhardt wrote:
> Hi all,
> I was qrv with my portable setup (25W into 2x8el X-yagi RHCP, 60cm dish)
> on Orbit 1010 (Jan 11th, 1300UT). While receiving the beacon clearly and
> strong, I was having real trouble hearing myself back.. I suspected a
> fault in my TX system and cancelled the session only to learn that my
> setup was perfectly working.. So I went into the telemetry from the
> weekend: have a look yourself!
>
> In the data file corresponding to Jan, 11th (A01010.tlm) if you display
> (with P3T software) the  AGC for the U-Band RX, you will get a
> interesting plot: AGC rises to up to 15dB at MA90 and staying over 10dB
> up to MA200. But there is a sharp noth at apogee around MA128 and guess
> what: it coincidences roughly with the transponder off time.
> But only roughly: There is a lag between the transponder and the high
> AGC values of 1 to 2 telemetry blocks. The U-Band RX has been on all the
> time, so this couldn't be radar interference.. this is the effect of few
> users running too much (15dB!!) too high power.. or in other words:
>
> A station using 100W could run with 3 Watts instead !! I am not kidding,
> read the reports from 1st transponder operations in May 2001..
>
> You could argue that this is LEILAs job: keeping down the AGC level. I
> don't blame the command team for this, because they have a hard job to
> do, even without tweaking around with LEILA (thank you guys for
> eveything!!).
>
> This is OUR job! Just make sure, that at least one station is stronger
> than you..Life would be so much easier especially for us QRP stations.
>
> 73s Achim, DH2VA
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