Topband: Recommended Relays

[Richard (Rick) Karlquist]

On 12/7/2018 12:53 AM, k3ky at radioprism.com wrote:

> (1500W) "...has excellent RF properties..." "In more than
> 20,000 hours of 24 x 7 operation with the four StationPro's
> in the author's station, there has not been a single relay
> failure."
> 

A somewhat more robust relay is the Omron MJN series.  Besides
being rated to hot switch 600VAC, they have a "dielectric strength"
of "750 VAC, RMS 60 Hz across open contacts" and greater than
2,500 VAC across any other pair of terminals.  I don't see
why this voltage wouldn't apply to RF as well as 60 Hz, unless
there is excessive heating of the insulation.
In any event, this is good for 1500W in a 450 ohm line at 3:1 SWR.
They work well for tuning a dipole or monopole across the 80
or 160 meter band by switching in capacitors.  There can be
substantial voltage across them.

The MJN is considerably bigger/costlier than the Schrack, but
not in the "contactor" class that is even bigger and costlier.

(Available from Mouser).

Rick N6RK