The AM Forum

How to not mount a glass vacuum relay.

Anyone have specs on a Kilovac H-12 relay? (not the one in the pic, that one is done broke)
Or a copy of a ~1980 Kilovac catalog?

This relay is not made now, and I found zilch on the interwebbie...

Pulled this relay from some HB gear I just picked up. Perhaps this is why the unit stopped working?

             _-_-bear

There be very nice ones from Russia on eBay.  Cheap, too, by comparison.

73DG

Dennis, based on your experience what are the minimum ratings for (A) antenna relay and (B) B+ relay in a
rig with 5-6kv on the plate... (I'm assuming headroom over a 4.5kv nominal B+). I guess there are two cases
here too, linear vs. plate modulated?

And, do you know what the difference is between "RF" rated vacuum relays and not??

I've looked at the ruskie relays. Bought American,  got a NOS military H-12 Kilovac coming... it's 12kv rated, but beyond that
I only know that it is higher rated than the H-8 that was in there (the broken one).

Surprised at the minimal info online. Kilovac does not return calls, no one picks up the phone. :(

The various Russki jobs have listed specs, and with vac relays the operating freq. range is no big deal.

KiloVac is most likely a CIA front op, you'll get a replacement on a 'need to know' basis ;)

73DG

same warning for glass relays as for vacuum tubes .... no lateral pressure to the pins .... only straight in line with the pins .... best to use something flexible, if possible

 ;D  Yikes -  I've made that exact mistake with the same vacuum relay about 25 years ago.  It usually happens when we try to torque down the screw fastener without terminal support. Even if the lead is flexible, the screwdriver torque can take out the glass seal.

Just so nobody else makes the same mistake:   The best way to torque the screw is to hold the floating / resting relay by its terminal (with needle nose pliers) while carefully torqueing the screw. This will keep all stress away from the glass. Any stress at all into the glass is a bad thang. And yes, flexible leads are the only way to go. Even a soldering iron can heat up a solid lead enough to mechanically expand it and crack the glass. Or, the lead heats the glass enough to make the seal fail - no vacuum, kaput!

A vac relay may be the most fragile part in any amplifier.... being made of thin glass and holding a vacuum.  Except for old buzzard glass tubes with plate caps and grid leads on the side, at least most tubes have sockets to eliminate direct connection failures.

T

I'll vouch for the communist relays.  Just as good as the capitalistic pig sourced kilo/jenning/gigavac sourced stuff where I've used it.

I can't remember which company was the split off by hams, but either gigavac or kilovac is very helpful when called and you identify as an amateur op.  The prices are even better to 'us'.

Since commie stuff is so cheap, it's been a no Brainerd on which brands to use.....  And the drop in American stuffs price sure reflects the competition of ebay.

--Shane
KD6VXI

ahhhh such a shame..Usually hard to kill those things; but glass is fragile