Dave,
I've looked at the automotive relays for RF use because they're easy
to find locally, and they have large, low-inductance contacts. But a
few years ago, someone on the reflector recommended another relay--one
that's already used in some commercial ham antenna switch products.
I've found them at Mouser, Newark, Allied, etc., and they price out at
less than $3.
I bought the Magnecraft 976XAX97H-12. This is the 12-VDC, 16 Amp
version. There are also 24-VDC, 120-VAC versions, and there is a
version with 20 Amp contacts. The important thing about these relays
for RF use is that the armature and its solder tabs is set between the
two stator contacts, and there's no need to have a wire leading from
the armature to the contacts, as there is in most other relays.
Some guys have put 3 kW or more on these relays (with low VSWR of
course). In design projects in my work, I've run these at 1200 VDC
without problems. The coil-to-contact breakdown rating is fairly
high--a couple kV if memory serves. Contact-to-contact breakdown is
less than 1 kV, but I've never had a problem with this when I've run
them at around 850 Volts. In the SPDT version, each pole and the
armature connects to two solder tabs, so you can get a pretty
low-inductance connection to the contacts. And by the way, these are
small relays---1"h x 1 1/8"w x 1/2"d.
Just a few thoughts....
Brad, KV5V
>> W5UN wrote:
>> Does anyone here have any experience using automotive type relays for
>> switching RF?
>> Dave, W5UN
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160 meters is a serious band, it should be treated with respect. - TF4M
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