[TowerTalk] Remote switching design choice

[John Tait]

Subject: [TowerTalk] Remote switching design choice


> Can someone explain to me why some remote antenna switch manufacturers use
> a scheme that supplies 12V to the relay box and switch the ground side of
> the relays to select antennas, while others supply a common connection and
> switch the 12V to the desired relay?  I can't see an advantage one way or
> the other,

I prefer to supply the voltage to the relay, as I think it's safer. If you
use the switch-to-ground system, it means that all the unused lines and
relays are sitting at 12 or 24v potential. If any of those lines short to
deck, then you've lost all control until it's fixed. With the other system
all unused lines are at ground potential. and if one of them decks out,
you've only lost one relay.. Also, all "floating" control lines have the
propensity to pick up, and re-radiate interference.

73,
 John EI7BA  http://www.iol.ie/~bravo/

 >and it does have the effect of creating incompatibility among
> makers' hardware.
>
> 73, Pete N4ZR
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