That is called "sealing current". It's been used in the telecom industry for ages. The spec is <20mA though, and you can get by with only a few mA. It helps to prevent various corrosive forces from damaging contacts in relays and the like over time.
The problem is that every time you switch you will get a very small arc at the contact point and you'll pick some of that up in the receiver. Regardless of the value of the "suitable choke" the arc will have a wide spectral content that will extend up into the lower HF bands. It might be possible to keep a sealing current on the system when it's not in use, and then go to a regular no-current (dry) system while operating. I'm not sure if that would accomplish the same function as having the current always present though. -Bill > One solution to the receiving problem when using high current relays may be > to have dc current (eg 100mA) pass through the contact in RX. > This would be particularly easy to implement when the antennas are zero > ohms at DC because the dc current source can then be placed in the shack > (with a suitable choke to isolate the RF from the supply and capacitor to > isolate the DC from the rig). > > - Paul > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband
