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Dish Antenna Radiation test pattern procedure

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sdanishsaleem
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Oct 29th, 2009 at 5:03am  
i need to know how we can do a radiation test , using SA
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Eric Johnston
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Reply #1 - Oct 29th, 2009 at 10:08am  
As a start read this: How to adjust antenna subreflector.

Don't proceed to any tests with the NOC until you have the antenna in focus and the first sidelobe balanced on opposite sides.

If you want to measure the receive pattern very far out then get the NOC to put up a really high power CW carrier.

To measure the transmit radiation pattern the NOC will tell you a suitable frequency to transmit a CW carrier.  Use a stable frequency reference for the carrier generator (e.g. modem) and upconverter to keep your uplink CW frequency stable.  The NOC will do the measurements (co-pol and x-pol pattern cuts) and send you the results by fax or email.   They normally will send you a detailed step by step procedure to follow.  It pays to spend a day practising first, simulating the complete test, without actually transmitting, just checking that everything works. 

To measure the transmit cross-pol isolation make the first test at the beam centre.  Then at 8 points in a circle around the beam centre, on a -1 dB radius.  Start by going left then up and round clockwise. It helps to have precision az/el position indicators, to 0.01 deg.

Best regards, Eric.
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« Last Edit: Oct 29th, 2009 at 11:33am by Eric Johnston »  
 
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Reply #2 - Oct 29th, 2009 at 11:06pm  
Hi,
You may follow the step-by-step instructions in Eutelsat's
"Earth station verification and assistance (ESVA) ESOG 130, Issue 2.0"
(for receive radiation pattern, see: chapter 11 -    RECEIVE SIDELOBES (INCLUDING RECEIVE GAIN)
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Admin1
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Reply #3 - Oct 30th, 2009 at 9:42am  
Download and save this document:
Eutelsat ESVA testing procedure ESOG-130 (1.45Mbytes pdf file)
Best regards, Eric.
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sdanishsaleem
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Reply #4 - Nov 10th, 2009 at 10:17am  
Thanks all for the support
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