Topband: Loud clicks

[Rick Karlquist]

Paul Christensen wrote:
> My long-term plan for the SPE amp is to replace the output relay with a
> Gigavac GH-1 and input relay with an Aromat/Matsushita RSD-12V.  The
> latter
> of which is now an obsolete part, but still available through AG6K, and
> some
> "bottom feeders" on the internet.  However, my short-term fix works so

I recently built a homebrew QSK switch using the Gigavac GH-1 relay
in the 12V version at the RSD-12V relay.  I tested the GH-1,
which is rated at 6 ms, and found that it pulled in in 4 ms,
applying 12V to the coil.  I applied 24V to the coil for the
first 3 ms and reduced the pull in time to 2 ms.  After the
first 3 ms, the voltage falls back to 12V.  The whole circuit
runs on 12V only and uses a capacitive charge pump technique to
pulse the 24V on the GH-1.  Simple RC timing circuits are used.
The RSD-12V relay is good for 2ms just applying 12V to it.
Power MOSFET's are used to drive the relay coils.  It works
perfectly with my FT-1000.

There is a special "HAM" price of something like $86 for the GH-1
when you order by email directly from Gigavac.

Rick N6RK