[Top] [All Lists]

Re: [Amps] Alpha

To: <>, <>
Subject: Re: [Amps] Alpha
From: "Dick Green WC1M" <>
Date: Thu, 5 Oct 2017 00:29:25 -0400
List-post: <>
> I figured out the life of a vacuum relay (RJ1, HC1, GH1, all rated for 2
> million cycles) in QSK contesting in CQing and also S&P.   When running
> (holding a freq and calling CQ) you get about 20,000 QSOs for the rated 2 
> million cycles, in S&P it's about 33,000 Qs, using my call as an example, 
> with the CQWW 
> contest exchange.
>Glenn AE0Q

At first blush that number looks very low to me. After all, there are quite a 
few very active contest stations here in New England that do 10,000-20,000 QSOs 
per year and you don't hear lots of stories about vacuum relays needing to be 
changed frequently.

But I think that's because the vast majority of highly active CW contesters 
don't use QSK for running. Too much noise, which gets really fatiguing when you 
do 3,000-4,000 QSOs in a weekend. Besides, many contesters grew up with amps 
that couldn't do QSK (meaning frame relays), so they've always used semi 
break-in. Some use QSK for S&P, but even then it's not all that necessary (if 
you're spending so much time in pileups that you need QSK, you're losing.) 

The number of relay closures for semi break-in is dramatically lower -- off the 
top of my head I think it must be 1/100th as many as QSK closures, maybe less.

Of course, relay closures have never been an issue for me because for the past 
22 years I've done virtually all of my contest running on an Alpha 87A. And in 
semi break-in at that. :-) I did have to change out the PIN diodes once, but 
that had little to do with cycles -- just a L1 arcing on the T/R board. I had 
to change out the relay on my Acom 2000A shortly after I got it because the 
factory had a bad run of HC1 vacuum relays. It's been going about 17 years now, 
though mostly for S&P duty.

I've been lucky -- I've been able to do numerous repairs to my 87A without 
having to send it to the factory. But I do worry about parts availability. That 
problem started a long time ago, and it will eventually force me to replace the 
87A. On paper the 9500 would be a worthy successor, but honestly I would want 
to make absolutely sure the amp doesn't still suffer from the problems it had 
early on. And it may be tough to justify investing in a tube amp with legal 
limit solid state amps getting better. 

73, Dick WC1M

Amps mailing list

<Prev in Thread] Current Thread [Next in Thread>