Dow Key Antenna Relay


Bill Pancake:
Can anyone explain to me how to correctly adjust the "internal" relay contact spacing on a vintage 60 series dow key antenna changeover relay?

I know that the SO-239 connectors are adjustable as viewed thru the end cover access hole. But what constitutes "correct" alignment & contact gap spacing so I get a good latch with no chatter?

This series relay is the one you see used by most hams for changing the antenna between a separate transmitter and receiver.  Thanks... Bill...K0JWP

Steve Katz:
The factory adjusted them for the correct spacing, so if nobody's played with it, it should still be set that way.

If someone has played with it, here's what I do:

Loosen nut on "receive" side (normally closed)connector, unscrew it until it loses contact with the relay lever arm, then screw it back in 1/8" to assure good, solid contact, and tighten nut.  Burnish both the SO-239 and the lever arm contacts with a very fine burnishing tool, which has a grit about equivalent to a piece of paper.

Now, loosen nut on "transmit" side (normally open) connector, and adjust it so that the relay lever arm travels 1/4" total from "RX" to "TX" and tighten nut.  Burnish both "TX" side contacts as above.

If anyone had ever taken a file or sandpaper or anything gritty to those contacts, they're probably shot forever at this point and need to be replaced.  The original surface was coin silver, which is soft and cannot be filed or sanded.  The normal burnishing tool is a dollar bill!

I've owned an awful lot of these over the years, and have visited the factory where they're made several times.  (Used to be in Minnesota many years ago, but has been in Santa Barbara, CA for a long time now.)



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