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
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
Harold Mandel
Superintendent of Construction
Baran Telecom Inc.
606 - 205 - 0172
hmandel@barantelecom.com
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|