Topband: Antenna relays

[Tom W8JI]

>I agree generally with these comments, except that my experience with
> CdAg contacts on receiving hasn't been that bad, provided that the
> application exercises the relays occasionally. Thus, using them as,
> e.g., an outdoor antenna switch where the antenna isn't regularly
> switched, and where there are large temperature fluctuations, can
> definitely lead to receive problems. At one point I thought about
> using a small dc bias current through relay contacts, but found it
> wasn't necessary.

With two relays in an amplifier, and maybe 5-8 relays in a switch, and 
thousands of amplifiers and antenna relays sold, and with Internet where 
even 1-2% failures creates a lifelong firestorm of "what they did wrong" by 
critical experts (who probably see less than one or two units a month 
instead of samples out of thousands), the perspective changes.

:)

The relays have to be gold flash, because silver has sulfidation issues. The 
contacts generally have to be small, or must have pretty high operating 
power for the relay size to allow high spring pressure.

This is all summarized, including links to outside relay information, at:

http://www.w8ji.com/relay_cleaning_and_life.htm