[CQ-Contest] VY1JA Tech Help Request.

[Scott Ellington]

Hi Jay,

It's really impossible to make relays that will handle both high power and
very small signals.  The gold plating is destroyed the first time high power
is applied.  One common solution is to use ordinary power relays, but apply a
DC bias of perhaps 50 mA when the contacts are closed.  Some RF chokes may be
required to complete the DC path, and possibly a blocking capacitor.  It may
be easier to switch in the bias only in receive mode, and only to the relay(s)
in the receiving path at the time.  There is no need to bias the contacts
while transmitting.

As for relays that will stand up to a VY1 winter, any RF relays specified over
the right temperature range should work.  The standard military range goes
down to -55 C, so I'd expect military surplus relays would work.

73,

Scott  K9MA


-- 
Scott Ellington
Madison, Wisconsin   USA

sdelling at facstaff.wisc.edu


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