"Greg_False" wrote in message
...
Hi,

I want to fit a receiving preamp to my 29MH mobile radio which runs a
50watt
linear amplifier. My plan is to fit the preamp at the base of the 102"
whip
and to switch it in and out of the co-ax circuit (when transmitting) by
means of relays activated by the mic press to talk button. Can I use any
12v relays, well shielded by copper boxes around them and what will happen
to my 50ohms impedance?

As you can see I need all the guidance I can get:)

Use one of these preamps. YOu will have to put it between the rig and amp
as they are only good for about 25 watts. They have the switching built in.

http://www.advancedreceiver.com/page7.html