Date: Sun, 04 Apr 2010 08:55:26 -0700
From: "Bill, W6WRT" <dezrat1242@yahoo.com>
Subject: Re: [Amps] Vac relay sequencing.. [WAS contact bounce]
ORIGINAL MESSAGE:
On Sun, 4 Apr 2010 07:11:37 -0700, "Jim Thomson" <Jim.thom@telus.net>
wrote:
>
>Sri for the diatribe, but I have extensive experience using the RJ-2 and
>RJ-6 vac relays. Your RJ-6, as configured above, will last 25 x million
>operations.... per jennings.
REPLY:
Be careful using the Jennings SPDT relays on 10 meters. They are
barely adequate for legal limit on 10.
## legal limit on 10m is 5.5A into 50 ohms.
## The Jennings RJ1-A is rated for 7A @ 32 mhz. That's 2450 watts CCS.
We used the Gigavac GH-1 ham, which is
the eq of the RJ1-A on the 2 x GS35-B 6m amp. The gigavac GH-1 handles
4.4 kw cxr.. and 4.7 kw pep just fine. [50.125 mhz]
[dummy load of course]. It won't blow up on 6m, when run way past it's
ratings. It's built like a tank.
The gigavac GH-1 ham will easily hi-pot test to > 7.5 kv. [$77.00]
## two GH-1 hams, with all contacts in parallel, is rated for 14 A CCS @ 32
mhz = 9.8 kw. If u want qsk qro,
this is the way to do it. Some extra Teflon sheeting between the connections
helps a lot. [ zero flash over]
Most of them are rated for
only 10 amps continuous carry current at 32 MHz. The one exception is
rated at 12 amps.
## the RJ2-B/C and the RJ6 are both rated for 10A CCS @ 32 mhz = 5 kw
CCS cxr.
## we used 2 x RJ2-B's, with all contacts in parallel on a YU-148. = 20A
CCS @ 32 mhz= 20 kw.
## 3 of em in parallel = 30 A @ 32 mhz = 45 kw.
## the gigavac G2 ham is gigavac's eq of a jennings RJ2-B/C RJ-6 . The
G-2 ham and G-2
have IDENTICAL specs.. so ignore the 'de-rated' ham specs for peak v and CCS
current. And that's
per my conversation with gigavac engineer on the phone.
Gigavac is doing hams a favour, selling the GH-1 ham, and G2-ham at
bargain basement prices. A regular G-2 sells for $400.00 The ham
version is $133.00
You can get the G-2 ham in threaded cylinders..[ highly advised].. and also
flange or threaded base.
You can also get it in 12 vdc or 26.5 vdc. You can get the GH-1 ham in
12 vdc or 26.5 vdc versions.
I'll use the GH-1 ham for both the input of an amp, and also the cut off
bias. Then, timing issues
are predictable, no contacts to ever clean, or get dirty from dirty airflow
into the plenum, no pitting,
no int contacts, etc. Flat swr on bypass mode. You can also run 2 kw through
it on BYPASS.
That feature alone, allows you to hook up several amps, nose to tail, in
series. A 1 in, 6 out, small
rotary switch ensures that only 1 x amp is keyed at any one time. Key line
from xcvr is fed to input
of rotary switch, with a separate output to each amps's input key line.
Then it's instant qsy.
If you have less than 2:1 SWR on 10 you should be ok, but with 2:1 you
will be slightly over the edge if your coax is at a current node. Not
a show-stopper necessarily, just something to keep in mind.
## the worse case scenario would be 25 ohm, pure resistive load, which is
very unlikely to happen.
IE: 7.7A into a 25 ohm load [ zero reactance] = 1.5 kw. A GH-1 will
handle that just fine.
later.......... Jim VE7RF
73, Bill W6WRT
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