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QRM on Oscar 100

Posted: Wed Jul 10, 2019 7:39 pm
by G4uvz
Switched on this morning and the usual MER of 8 + on the beacon was just 4 and a bit

Checked on Goonhilly and all looked normal.

Out to the dish to see if the LNB was at 7 o'clock..all OK

Yesterday I re-instated my wideband 10 Ghz link to my friend G4UTM 8K across the valley ...an lnb turned inside out to transmit on 10Gz with about

10 mW output on 10370 ..the dish is behind the 1.2 M dish pointed at Oscar 100 but obviously enough adjacent signal to upset Minitune !

Switched off the tx and 8.3 MER restored

Re: QRM on Oscar 100

Posted: Wed Jul 10, 2019 8:04 pm
by g0mjw
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QRM - blocking perhaps or wideband noise.

The beacon signal also goes down when other signals are on the transponder.

Re: QRM on Oscar 100

Posted: Thu Jul 11, 2019 2:08 pm
by G4uvz
MER 10.2...how big is your dish!!??

Re: QRM on Oscar 100

Posted: Thu Jul 11, 2019 3:00 pm
by g0mjw
It's 10.5 - 10.6 when other stations are not on. The dish is 2.4m but I am concerned it is not optimum as others (including me) see similar figures with 1.2m dishes. However, the maximum MER is limited by the uplink so above 10 it's difficult to see differences.

Mike