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Re: [Amps] QSK (okay, not QSK...)

To: g8gsq@eltac.co.uk
Subject: Re: [Amps] QSK (okay, not QSK...)
From: HAROLD B MANDEL <ka1xo@juno.com>
Date: Fri, 24 Feb 2006 14:01:04 -0500
List-post: <mailto:amps@contesting.com>
Hi Steve,

In my big amp I use an RJ-2, and in the little amp an RJ-1.

Neither of these are cheap, and there's more to do than
fidgeting around inside an amp, replacing vacuum relays.

The original Alpha 77 series have an RJ-1 as an output
relay and a Magnecraft reed relay as the input relay.

Neither of those are simple repairs, and good luck finding
a replacement Magnecraft reed job. I went with an
RJ-1 input and RJ-2 output after finding the input relay
trashed from 30 years of flopping around, and the RJ-1 output
was iffy because of all the RF amperage going through it and 
I have heard horror stories of '77's cooking their output relays.

The '77 manual says the original setup will track 50WPM,
but without a complete refit an owner might expect a fault,
especially at 20WPM or thereabouts, and what if that fault
involved a hot switching and a subsequnet 8877 failure?

I dunno, Steve.  I think I'd rather go for the MTBF
reliability side of the curve and let the relays settle down......

'73,

Hal
W4HBM
On Fri, 24 Feb 2006 07:40:25 +0000 Steve Thompson <g8gsq@eltac.co.uk>
writes:
> 
> 
> Jim Tonne wrote:
> >> I think I'm starting to get depressed with this exchange . . .
> >>. . . some others are enjoying it . . .
> > 
> > 
> > Echos my sentiments.  I just came back from Home Depot 
> > after having picked up a fire extinguisher.
> > 
> > Awaiting the "we're through with it" comment!   :-)
> Going back to a question posed at the outset about relay life... The 
> 
> reflector is not full of people saying that QSK trashes their 
> relays. On 
> the other hand, my mental arithmetic (far from reliable these days) 
> 
> comes up with an estimate of 120-150k operations for a heavy duty 
> contest weekend - a sizeable percentage of expected lifetime. 
> Ensuring 
> cold switching will presumably help, but mechanical failure is going 
> to 
> be a factor at some point.
> 
> Steve
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> 
> 


Harold Mandel
Superintendent of Construction
Baran Telecom Inc.
606 - 205 - 0172
hmandel@barantelecom.com
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