SatSig topic:

observation of unwanted carrier on 5300

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Aug 8^th, 2008 at 5:21am

Hi all
I have 5300 satellite routers, running on TDMA configuration, version 7.0.5. The router is not connected to any ODU and is not in network.The Tx port is connected to Spectrum analyser and Rx port is open.i need to test them on table using CW carrier generated in router at different l-band frequencies.

When a Tx freq is entered either through Console or through telnet, i observe a modulated carrier even before tx CW is switched ON.This carrier is of low level just above grass noise.I observed this at different l band frequencies.when the Tx CW is switched ON the required signal appears over the previous mentioned low level carrier.

Kindly suggest how to avoid the above mentioned low level carrier which appears even before Tx CW is switched ON.
Thanks in advance

Aug 8^th, 2008 at 11:54am

I have always observed that "L Band nub" when connected locally (with a SPECAN) to a line card or modem. It appears to be a very low Lband presence at the center freq. I have never had the time to hunt down what it is, but I can confirm your findings that it is certainly there and is not isolated to your config (read: it is common to all). I recommend calling the TAC if you want a solid answer to the source of that energy.