[Premium-Rx] The Ghost of Racal Past

[Ron Ott]

My 3711 has been visited by gremlins from the Ghost of Racal Past.  The fundamental problem with my 3711 was the internal 5MHz reference osciallator.  As a result, LO injection levels were low and the BITE indicated a couple faults: low 2nd LO level and RX gain failure (but not a reference oscillator problem).  The 3701 and 3711 receivers are different in some important ways and my 3701 manual raised more questions about LO frequencies and voltage measurements than it answered. 
 
Nevertheless I eventually wound up checking the 5MHz Reference Oscillator output that turned out to be the problem. Using my HP sig gen as an external reference the 3711 came to life and also passed the BITE test. 
 
But more gremlins: I switched back to the internal reference oscillator to check whether the BITE errors would come back, and the 3711 still works fine. For how long, I don't know, but I now know there is some funny business with the reference oscillator (Bad cable or connector??? Int/Ext switch contacts??? Who knows?)
 
Thanks to all who came to my assistance with Racal information, I'm in a good place with the 3711 right now and hoping to stay there. Let's hope the Ghost of Racal Future is kinder.
 
73, Ron W6XY