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Preamp bypass circuit



I have recently built up a GasFET preamp for use on the 2 meter band on
AO-10.  To switch the preamp out during transmit, I have built up a RF
sensed circuit which bypasses the preamp through a relay.  The problem is
that I can observe a breif RF transient that would go into the preamp (I
actually have not hooked up the preamp to the switch circuitry yet) before
the relay switches into the bypass mode.  I am fearful that this RF
transient would be enough to blow out the GasFET.  Does anybody have any
hints or ideas how to supress this transient so I won't be replacing the
FET?

My rig is a FT847, and so I though another idea would be to switch the
preamp out of the transmit path by using the 847's PTT accessory jack.  But,
I don't think that the results would be any different unless there is a way
to delay the power output stage from coming up at the same time as the
switching of the PTT accessory jack signal.

How does everyone else get this to work on their homebrew preamps?

Thanks
Jon
KK7RZ

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