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Happy Birthday UO-11

Hi All,

I was listening to the S beacon of UO-11 at 2401.500 MHz 
+/- doppler to day 1 March 2004 during two Northbound orbits,
the first one with AOS at 14:16 and the second one with 
AOS at 15:52 from JN70ES

The carrier of the beacon was peaking max 12 dB over the noise
with a slow QSB  and the level was changing slowly from 8 to 
12 dB over the noise as seen on a spectrum analyser connected to 
the S band converter 145 MHz IF

Doppler was about +45 KHz at AOS and the beacon appears
at about 2401.545 MHz on acquisition. 

At TCA i.e. the Time of Closest Approach the frequency
appears to be 2401.505 MHz i.e. about 5 KHz higher than

At LOS the doppler was about -45 KHz   

I was receiving UO-11 with the same S band setup used for AO40
i.e. 1.2 meter dish with 3 turns helix feed and 110 kelvin overall noise
temperature receiving system.

In this receiving system the AO40 MB was strong about 21 dB over 
the noise at apogee with low squint angle.

I do not recall exacly if the S band antenna of UO-11 is LHCP or RHCP 
but looking at a pictorial it seams that UO-11 uses two different LHCP 
helices and we are receiving using RHCP antennas !

It would be very interesting to have exact information about the S band 
antenna polarization of UO-11

I  recall very well that the S band beacon  of  UO-11 was very usefull for 
many of us in preparation of AO40 and it seams that the UO-11 signal 
strenght at 2401.500 MHz is not to much reduced.

The S beacon of UO-11 can still do a nice job now for beginners preparing
for the future with P3-E  

Nice birthday to our old friend satellite UO-11 !

73" de 

i8CVS Domenico


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