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Re: [Amps] Relays

To: 'Amps' <>
Subject: Re: [Amps] Relays
From: Paul Kelley N1BUG <>
Date: Mon, 31 Mar 2008 07:47:12 -0400
List-post: <">>
Nice work Larry.

I haven't personally tested enough radios to be sure but I have a 
strong hunch most of the newer radios are better than some of the 
older ones in this respect. The radio with 3 ms was a much older 
Icom (740). Very scary.

With firmware upgradeable radios watch out for changes with upgrades 
though. My current radio used to have 15 ms between assertion of amp 
control logic to RF output. After a firmware update it dropped to 7 
ms. Some radios also have more than one possible means of 
controlling an amp - eg. a set of relay contacts intended for that 
purpose and an open collector output which is often 1 to 3 ms 
faster. I used the latter with a homebrew interface in order to give 
my amp's vacuum relays a little extra time to switch (in this case 
they don't need it, but it makes me feel better!)

Paul N1BUG

Larry Benko wrote:
> I was interested in the same topic a few years ago and I made a bunch of 
> measurements on some Icom radios.
> Look at
> Bottom line was for all the all the radios I measured I never saw 
> anything like 3mS on relay closure.  However both the IC-706 and IC-7000 
> have a negative holdover on the relay release in the full QSK mode which 
> is quite scary.
> 73,
> Larry. W0QE
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