Topband: RELAYS

[Mr. and Mrs. Magoo]

For the past few years I have been using surplus SPDT relays with 30A
contacts to switch all my Beverage lines some distance from the house, and
also to switch bands on the 160/80 vertical at our summer home.  On the
Beverage system, every antenna is grounded until pulled off ground by the
relay.

On the TX antenna I have not had any problems switching 800 watts on either
band.  Resting position is 160M and pulled position is 80M.  Minus 30C or
plus 30C temperatures there have been no problems.  The relays in the TX
system are well insulated from ground and heavily decoupled.

The particular units I use are made by Deltrol Controls and have a contact
spacing of about 3/32".  They are 10V and require about 100 ma to pull, so
300 ft of control line and a 12V power supply works out well.

I don't think you can over-engineer a switching system, especially when you
might be faced with a long cold trek through the snow some blizzardy night! 
My indoor Beverage routing control box using small encased 12V SPDT relays 
has had several relay failures.  When I rebuild this unit I will use the 
same style of relay I have been using outdoors.

Bill, VE3CSK