New perspective? Re: [1000mp] Sticking relay problem

Wed, 24 Mar 2004 22:05:23 -0800

Interesting thought exercise. However, in my case, the problem first
appeared on the other side of the planet (3B9R) and was still there when I
got home. I also have enough antennas to know that the problem manifested
with all of them.

Garry, NI6T

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Scott Galbraith
Sent: Wednesday, March 24, 2004 5:05 PM
To: [email protected]
Subject: New perspective? Re: [1000mp] Sticking relay problem
Importance: High

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I've noted and just "read the mail" on this topic several times over the
past few years. I don't normally get too involved in these things because,
even if I experience a similar problem - I rarely have time to really
diagnose and provide detailed engineering perspective.

However, thought I would finally throw another factor into this equation
based upon my own problem/solution.  It may be that the focus on the
"sticky relay" is a focus on a "symptom" rather than the root cause.

I have experienced the described problem at least three times over the past
2 years. It was baffling and not "consistent" that I could tell at first.
Twice it "cured itself". The third time I effected a cure and upon
reflection decided that the cured item had also been an existing parameter
in each of the earlier two circumstances - but I had not correlated it at
that time.

All three times that this problem happened, I had antenna problems - and
not necessarily very obvious ones and in at least one of the cases also a
shack ground problem. The antenna problems were associated with broken or
intermittent shield or center conductors in feedline and the ground problem
was present the first time that I experienced this failure. The antenna
problems were not immediately obvious because they were intermittent (as
the wind blew) and/or the Quadra and external tuner box were masking the
immediate impact (things appeared to work at times even when they were
not!)  In all three cases, when the ground and/or antenna problem was
fixed, the "sticky relay" problem went away on it's own - immediately. The
third time I empirically established the relationship by recreating the
antenna problem and observing the immediate return of the "sticky relay"
problem.

Therefore, I suggest that the  relay/switching problem may be related to
excessive RF in the shack and/or ground-loop situations which may not be
enough to prevent loading and apparently successful operations - but may be
enough to affect the relays or their driving circuitry. This might also
explain why shops, using good antennas and/or dummy loads (and probably no
linear) might have difficulty recreating the problem observed by the
equipment owner.

Those of you with more time and test equipment than I have may wish to
tackle this problem from a different direction and see if you can observe
the same correlation that I have noted. As I said above, I had this problem
3 times, it was fixed all three times without any work on the rig and I
have never experience the problem when my antenna/ground system has been
connected and functioning properly. My use had been in net, contest and dx
oriented operations and I almost always am running the amp for those
activities.

- For what its worth, my 2 cents.
--
73 de Scott Galbraith
N3OK, Frederick County, MD
FM19ji
ARRL, QCWA 30013, GERATOL 2198, PVRC
NAVMARCORMARS - NNN0OPY, NNN0GAW
National Communications System SHARES
mailto:[email protected]

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