Amps
[Top] [All Lists]

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

To: HAROLD B MANDEL <ka1xo@juno.com>
Subject: Re: [Amps] QSK (okay, not QSK...)
From: R.Measures <r@somis.org>
Date: Sat, 25 Feb 2006 04:52:24 -0800
List-post: <mailto:amps@contesting.com>
On Feb 24, 2006, at 11:01 AM, HAROLD B MANDEL wrote:

> 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,

In my experiences, an RJ-1A will not do 50wpm without a speedup circuit 
to decrease its make time from c. 6mSec to 2mS.   see  
http://www.somis.org/D-a-07B.jpg

> 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
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org

_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

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