George Cutsogeorge wrote:
> At Top Ten Devices we have been using the same relays in our antenna
> switching products for about 15 years now. They are the Aromat JW1FSN-DC12V
> types. They are sealed with 10 amp contacts and have high voltage
> insulation. Aromat has become Panasonic Electric Works. These relays are
> available from many sources and are shown in the Digi-Key catalog at $2.67.
> Many thousands of these relays are out there in our products and they don't
> come back. Note that in all cases the designs use the normally closed
> contacts for grounding and the normally open contacts to pass the tx power
> and the rx signals. i.e. We don't use the normally closed contacts for
> passing signals. It may take extra relays to design like this, but there
> are never any receive signal failures.
>
> In my own SO2R station there are 47 of these relays in use and there has
> never been a failure in the 12 years since I started building in Oregon.
>
> George, W2VJN
I'm getting a bit confused! We have two different relay discussions
that have seemingly merged into one.
The first questioner asked about relays for a strictly receive
application. Unless one wants to complicate things by arranging
to pass some current through the contacts, the only valid choice
seems to be gold contacts. These are designed for "dry" circuits
and will not handle any appreciable power.
The second questioner asked about a relay to disconnect his
inverted L during receive periods. George, W2VJN, gave us info
about a relay he has used with great success. However, there is
another consideration in this application and that is switching
time. I normally use semi-QSK and need a fast relay so I advocated
using a vacuum relay. If one operates SSB or uses a footswitch or
some such PTT arrangement, then switching time is not so important.
73, Roger
--
Remember the USS Liberty (AGTR-5)
http://ussliberty.org/
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