Well, everyone, I have finally figured this out. and it turned out NOT to be
anything anyone had suggested.
After trying two other PA assemblies and seeing no improvement in receive
sensitivity, I decided to try a different RX filter hybrid. When I removed
the one in the radio, I noted that
Yes there have been many 900 Spectras over the years that exhibit poor receive
sensitivity. Check the Rx/Tx antenna switch diodes. The receive shunting diode
may be shorted. This is caused by high reflected power.
The RF amp/mixer transistor goes soft and looses gain.
Mark n9...@... wrote:
Thanks!
Unfortunately, I do not have board layout or schematic diagrams with which
to locate the parts you referenced - can you send me a scan or photo of a
board indicating where the diodes might be? I also assume the RF amp/mixer
transistor is somewhere else, yes?
Mark - N9WYS
n9wys (at)
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