[VHFcontesting] Multi-pole relays with 28V common??

John D'Ausilio jdausilio at gmail.com
Fri May 8 17:17:58 EDT 2020

Ok, more info ..
Inside is just coils and steering diodes.
One relay showed common connected to frame, other one was fine. On opening
the bad one, frame connection disappeared. Reassembled and now works fine.
Maybe it was shorting the common to the top of one of the diodes. I may
open them back up and apply some kapton around the end of the PC boards.

On Thu, May 7, 2020, 19:17 John D'Ausilio <jdausilio at gmail.com> wrote:

> I've had a pair of 1P3T SMA latching relays in my relay box for a while,
> and thought I'd use them for a 144/222/432 switching box for my K3. They
> have one terminal marked +28V(COM) and three terminals marked -1, -2, and
> -3. For some reason, the +28(COM) terminal is actually at RF ground, which
> I realized when I connected system ground to the chassis! I see in various
> catalogs that these relays are offered with negative or positive common ..
> how the heck can you actually use a positive common relay without having
> the chassis at +28?
> Dynatech M3-413D38FT
> de w1rt/john

More information about the VHFcontesting mailing list