I don't think I have the service manual for the "B" model; I am not sure if
the original R8 is similar.

Pete

starman wrote in message
...
Pete,

When you get the time, take a look at the PC board layout of an R8B,
especially the top RF board. I guess the lowest board with the
synthesizer should be considered the noisiest one. It's located under
the chassis, apparently for shielding purposes. The SW8 is similar. I'm
going to revisit my R8B with your PC board grounding suggestions in
mind. Thanks again.

Pete KE9OA wrote:

Anytime! Anyway, it is a good idea to bring in the power supply return
(ground) wire to the noisest part of the circuit board; this way, the
ground
is "cleaner", the further you get away from that section of the board.
When
you are laying out the board, make sure that you locate the low level RF
circuitry as far away as possible from the noisy circuitry, and NEVER
connect the ground return wiring from the power supply to the low level
RF
section of the board. If this is done, the return currents of the noisy
circuitry will flow through the ground plane in the low level section.
This
noise will modulate the RF section, and be superimposed on the RF
output,
possibly causing undesirable spurs, high phase noise in the VCO, etc.

snipped


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