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Re: [Amps] Amplifier lifetime

To: "'Bill Turner'" <>, "'Amps group'" <>
Subject: Re: [Amps] Amplifier lifetime
From: "David Harmon" <>
Date: Fri, 6 Oct 2017 01:47:39 -0500
List-post: <>
Array Solutions made a 'bias switching' box that essentially has the amp
antenna relay keyed all the time and the bias was switched.
I know of a guy that had one installed in his Henry 3K-A and I was
considering installing one in my 3K-A but I never followed through with it.
This was 4 or 5 years ago and I don't recall exactly how it worked just now
but as I was pretty slick.


David Harmon
Sperry, OK

-----Original Message-----
From: Amps [] On Behalf Of Bill Turner
Sent: Thursday, October 5, 2017 10:53 PM
To: Amps group <>
Subject: Re: [Amps] Amplifier lifetime

One thing a person can do to extend relay lifetime is to verify there is no
hot switching going on. Many modern rigs have a built in delay between amp
keying and actual RF output, but many older rig s do not. 

A dual trace scope with one input on the keying line and another on the RF
output will give the answer. A typical relay takes about 20 mS to switch so
any delay less than that may be trouble. Remember there are two relays which
have to switch - one in the transceiver and one in the amp. Be sure to check
both key down and key up times. 

One method I have heard of but never used myself is to key the amplifier
first and then have the amp key the transceiver. Simple enough on key down
but key up is a little more complicated. You need some kind of logic box to
unkey the transceiver first and then unkey the amp, just the reverse of key
down. Perhaps such boxes are available on the market?  I haven't ever seen

73, Bill W6WRT
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