Many station are upgrading their 2, 7, 13, 18, and 23 GHz Duplexed STL / TSL systems, and, instead of GAINING fade margin, they are LOSING both Fade Margin AND video Signal to Noise Ratio. Those with digital feeds find their on-air signal freezing for no apparent reason. This is normally a case where the old receiver worked OK, but just couldn't handle the fades.
This happens quite frequently when you connect a new, sensitive receiver to an old duplexer. Newer receivers have about 20 db (or more) front end gain (built in LNA). The problem comes from 3 places:
1) the transmitter's reflected power from the antenna appears at the receiver, and causes desense or overload,
2) the wide passband of the duplexer's receive filter allows transmit RF to appear at the receive port, and the more sensitive receiver is overloaded.
3) the wide passband of the duplexer's transmit filter allows transmitter power and/or sidebands to enter the receiver, and some of them are close to or within the passband of the receiver.
If you can kill the STL or TSL transmitter and all problems go away, you can solve this problem by having us retune your duplexer(s) to provide additional rejection between the transmitter and receiver ports on the duplexer.
Give us a call at 1-954-850-1016
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