Jim:
I control my latching relays with one control line plus ground. It requires
two voltages [+ / - ] and a simple RC circuit in each + and - source used to
feed the control line for the relay.
The RC circuits provide a big current pulse when switching and then limit
the current to a much lower value once the transition has taken place.
Tod, K0TO
Sent via my DROID X
-----Original message-----
From: Jim Thomson <jim.thom@telus.net>
To: towertalk@contesting.com
Sent: Mon, Dec 27, 2010 08:40:22 GMT+00:00
Subject: [TowerTalk] Gigavac Relays
Date: Sat, 25 Dec 2010 20:53:40 -0800
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
Subject: Re: [TowerTalk] Gigavac Relays
On 12/25/2010 6:52 AM, Howard Hoyt wrote:
> Howdy and Merry Christmas all,
>
> I maybe restating common knowledge here, but I just discovered that
> Gigavac has a special program to sell HV/RF relays to hams directly at a
> really reasonable cost:
>
> _http://www.gigavac.com/products/relays/ham/index.htm
> <http://www.gigavac.com/products/contactors/datasheets/gx14/index.htm>_
>
I can report that the ham purchase program works as advertised
for about $85. I bought the 12V version and rebuilt
my homebrew QSK circuit for my linear. I used the speed up circuit
shown here:
http://members.cruzio.com/~k6xx/radio/fastrely.pdf
Using this, the turn on time is less than 5 ms.
Although this circuit doesn't speed up release,
it was already under 10 ms.
The whole thing runs on +12V including the reed
relay for the radio.
I had previously used Rich Measures' QSK circuit,
which was very inconvenient because it required
100V, which I didn't happen to have (my linear runs on 48V).
I kept the reed relay from that circuit to use in the
new one. BTW, the reed relay doesn't need any speed up.
It's something like 2 ms from the factory.
The 28V vacuum relay in that circuit failed.
I had bought it surplus, used. I think its worth the
extra money to get a new one.
The dimensions of the current relay are slightly different
from my old surplus one. I had to slightly enlarge the
mounting hole. They converted to metric dimensions.
The new relay still has the same flimsy coil connections,
be real careful you don't bust them off.
Rick N6RK
### BTW, I talked to the Gigavac eng a few yrs back...and although the
'ham' version of
a G-2 , GH-1, and G41 and G-12 all are depicted with lower peak V and
lower CCS RF current ratings,
such is NOT the case per the gigavc eng I talked to. The G2 and G2-ham
have IDENTICAL specs. The ham
version is "de-rated' to appease commercial user's, so they don't think
they are being ripped off. Max gain
systems sells the GH-1 for less than the Gigavac GH-1 ham version
anyway....and no max limit of 3 x relays per
yr either. The Kilovac version is far mote robust than the jenning's
RJ1-A.... which is why Alpha switched from
jenning's to kilovac years ago. The gigavac version is better than both
of them. The GH-1 will consistently hi-pot
test to > 7.5 kv. Max gain systems has excellent pricing on the entire line
of gigavac relays, including the G23, G52, G-9
and G2.
## Kilovac engs told me years ago, If you are limited with vdc...and you
want to speed up a 26.5 vdc relay.... then simply
use the 12 vdc version instead. With 24-30 vdc applied with a simple drop
resistor..they operate blazing fast. If you want em still
faster, then use a small 50 uf lytic across the drop resistor, then it
becomes a 'RC hot shot circuit' . If you have +48 vdc available,
you are laughing.
## I had no problems with building a +120 vdc supply, using a FWD..for
use with speeding up a 26.5 vdc vac relay. I use a
P+B ODC-15 or ODC-15A opto isolator..with a 8-18 vdc input. The opto
has 4 kv primary to sec isolation, and operates in < 100 microseconds.
RlS time of the same opto is 750 microseconds. Current draw on the 12 vdc
opto primary is just a few ma.
## For applications for ant use..such as the ultimate trbl free remote
ant switch box's.... or for shorting out coils at the feed-point of DE's,
etc... you can get many of the gigavac relays in a latching version. I
find the 'hold' voltage [ min voltage to operate a vac relay] to be low
enough
that I usually don't bother with the latching version. The latching
versions all use 2 x coils. With a com between em... you still require a
min of 3 x control leads to operate em. Any 13.8 vdc supply will work with
them. You can also get many of the gigavac relays in either a threaded
base or a flanged base. You can also get many of then with threaded
cylinders... instead of soldering... which makes using strap or sta-kon
connector's
a snap.
Later.... Jim VE7RF
------------------------------
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