Dick.... I don't have quantitative information such as how many contests,
qso's, etc my 77dx has seen in the last 16 years, but for what it's worth,
last month I replaced the RJ1A relay for the 2nd time (i.e. I'm now on my
3rd relay). 73 Noll W9RN
----- Original Message -----
From: Dick Green <dick.green@valley.net>
To: <amps@contesting.com>
Sent: Sunday, July 04, 1999 3:27 PM
Subject: Re: [AMPS] RJ-iA relay contact-life on CW?
>
> Hmmm. Let's put together a little thought experiment on how long an RJ1A
> should last a contester.
>
> Rich says the RJ1A is rated for 2,000,000 closures.
>
> Lately, I've been averaging about 2,000 QSOs in the big contests. Figuring
> an average of five characters in each callsign contacted, the average
> exchange is about 18 characters when running stations (callsign, RST,
> exchange, TU, WC1M) and about 12 characters when doing search-and-pounce
(my
> call, RST, exchange.) I probably do 75% runs and 25% S&P. I figure the
> exchange has to be repeated about 15% of the time. If the average number
of
> elements per character is 3, then I end up with about 114,000 relay
closures
> for the exchanges.
>
> Figuring CQs is a little harder. A CQ costs 14 characters (I like to send
> "CQ TEST WC1M WC1M".) During big runs, I hardly ever call CQ. Maybe once
> every 5-10 minutes at most, probably less. During slow, steady runs it
might
> be more like once per minute. During very slow periods, I probably call CQ
> 4-5 times per minute or more. Let's say I operate for 30 hours, 22.5 of
> which is spent running stations. Let's say the run time is equally divided
> between big runs, slow/steady runs and very slow runs. That comes out to
> about 2325 CQs in the contest, or another 97,650 relay closures.
>
> Altogether, that's well over 200,000 relay closures for one contest. Since
I
> try to operate in the five big CW contests each year (Sweepstakes, CQWW,
> ARRL DX, CQWPX and IARU), an RJ1A relay is only going to last me about two
> years! Yikes.
>
> But I don't use QSK for running stations. In fact, I suspect that very few
> CW contest operators use QSK, unless they do only S&P. Listening to loud
> static, noise and QRM (and AGC pumping on some radios) between every
element
> can be exhausting over a couple of thousand contacts or more. I love QSK
for
> chasing DX, and high-speed ops love it for ragchewing, but it really isn't
> all that helpful when running stations in a contest. I do like to use QSK
> for S&P contacts, which are more like chasing DX. But that's responsible
for
> a relatively small percentage of the relay closures.
>
> Some ops have said that they set the VOX to drop out between words. This
> would cut the number of relay closures to fewer than 20,000 per contest,
> extending the relay life to nearly 20 years! However, I find no reason to
> listen between words, so I set the VOX to drop out at the end of each
> transmission. Setting the VOX this way results in less than 5,000 relay
> closures per contest, so the relay should last a lifetime.
>
> I should add that I use an 87A with PIN diodes on the run radio anyway.
But
> I don't use QSK for running stations, even though I can. The amp on the
> second radio has an RJ1A, but the S&P duty cycle on that amp is very low.
>
> 73, Dick WC1M
>
>
>
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>
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