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[TowerTalk] Gigavac Relays

To: <>
Subject: [TowerTalk] Gigavac Relays
From: "Jim Thomson" <>
Date: Mon, 27 Dec 2010 00:40:22 -0800
List-post: <">>
Date: Sat, 25 Dec 2010 20:53:40 -0800
From: "Richard (Rick) Karlquist" <>
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:
> _
> <>_

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:

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 
a snap. 

Later.... Jim   VE7RF



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