K3 Receiver troubleshooting

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K3 Receiver troubleshooting

Rick Stealey
My K3 suffered a sudden loss of sensitivity this morning.  Yes, there was lightning last night.  The antenna input was grounded in an antenna switch but the receive antenna port was connected to a Beverage.

It appears to be normal in every other way.  Transmitter ok.  Receiver functions work, like preamp, attenuator.  But the level is down >60 db.
It is the same on both the antenna jack and the receive antenna port on the KXV3.

I have some lab equipment (HP sig gen, spectrum analyzer) and made some quick checks but I need a sanity check:
With -40 dbm into the receive antenna port the S meter is S7.  
With -30 dbm input, The spectrum analyzer connected to the IF output shows -80 dbm.  I'm assuming this is WAY off, and should approximate the level of the input signal.

So I think I can safely assume the problem is not in the IF or downstream, but a likely culprit would maybe be a switching diode in the receive path?  Any ideas?

Rick  K2XT



     
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