At 4/22/2007 12:21, you wrote: >What value of cap should be used as a minimum for TX RX controller >inter-connection. 1000pf, 5000pf? > >Doug - GM7SVK
Jeff's answer completely & accurately answers the question; I can only offer my personal choices of filter types & values. For any DC supply lines, I use L-C or pi=network EMI filters. They're essentially brick wall filters at RF (-70 dB). Only problem is the shunt capacitance of these filters is usually too high to use on any non-DC signals. For those I use 1000 or 5000 pF feedthru caps with a small value of series resistance to assure that the cap can shunt enough stray RF. Series coils or beads are a good idea too but I worry about the 1% possibility of a series resonance occurring right at the frequency that needs to be blocked. OTOH a carbon resistor should maintain its resistive properties up to at least 500 MHz. Bob NO6B
