What about RF getting into a relay maybe ?
----- Original Message -----
From: "Guy Olinger, K2AV" <k2av@contesting.com>
To: "Bob Henderson" <bob@cytanet.com.cy>; "TowerTalk"
<towertalk@contesting.com>
Sent: Tuesday, June 18, 2002 11:10 PM
Subject: Re: [Towertalk] WX0B Six-Pack
> 1) The design is not bad. Too many of them out there working FB for
> that.
>
> 2) You say relays, assuming you really mean more than one exhibits the
> problem.
>
> It is unlikely that six relays are all bad with the same problem
> unless there was a bad batch. As in Jay got a box full of 18 volters
> mislabeled 12 or some such. That would have showed up as a serial run
> of bad units, which he would have found about, and knowing him, would
> have quickly owned up to and offered a replacement unit. Jay would
> have been happy to get all the defective units back.
>
> So I will speculate that there is something wrong in the common
> return, or the power supply's output voltage is dropping drastically
> under load.
>
> Could be in the six pack box itself, as in solder joint, a bad piece
> of wire (yes, even 3 feet of wire could have a conductor problem
> inside the insulation. I once had a piece of zip cord that was MISSING
> a foot of wire inside the insulation, as came from the factory).
>
> With the voltage on one of the relays, measure the voltage AT THE
> COIL. And measure it at the power supply. Low at the power supply,
> chase the power supply problem. OK at power supply and low at the
> coil, start chasing a common ground path problem.
>
> Good luck & 73, Guy
>
>
> ----- Original Message -----
> From: "Bob Henderson" <bob@cytanet.com.cy>
> To: <towertalk@contesting.com>
> Sent: Tuesday, June 18, 2002 2:17 AM
> Subject: [Towertalk] WX0B Six-Pack
>
>
> > I am wondering if any Six-Pack users out there are experiencing the
> same
> > problem I am.
> >
> > I have found my Six Pack to be rather unreliable. The problem is
> that the
> > relays don't always operate in such a way that a reliable contact is
> made.
> > The typical failure is that one or other of the relays fails to pull
> in
> > properly. I spoke to Jay at Array Solutions and he told me that the
> spring
> > tensions on the relays needed to be adjusted to ensure that there is
> enough
> > tension to cause the necessary wiping action on the N.O. contacts.
> At the
> > same time this tension has to be not so great that it overcomes the
> capacity
> > of the relay coil to cause the relay to close properly when power is
> > applied.
> >
> > I have adjusted endlessly but I have not been able to find a
> reliable
> > operating set-up through this adjustment. It seems to me that when
> > increasing spring tension I find the point that prevents relay
> closure
> > before I find the reliable N.O. contact wiping tension.
> >
> > It seems to me, though Jay disagrees, that there is a design flaw in
> the
> > Six-Pack. I have used DX-Engineering and Top Ten Devices switch
> boxes at
> > the top of towers in hostile environments for years and never had a
> problem.
> > This Six-Pack sits in the shack at the back of my operating desk and
> it is
> > so unreliable! At least it is close enough so I can give it a kick
> when a
> > relay doesn't pull in properly.
> >
> > To me that the idea of a fine adjustment of relay spring tension to
> find a
> > position where the relay reliably closes but at the same setting
> will open
> > with the necessary force to properly wipe the N.O. contacts has no
> place to
> > be on an antenna switch. Surely this is marginal design?
> >
> > On my previous antenna relays I have found that nominal 12V relays
> would
> > operate with as little as 8V applied which meant that with 12V
> applied the
> > really clunked in well. With these units there was no delicate
> adjusting of
> > spring tension either....they wiped the N.O. contacts reliably from
> day 1.
> >
> > Does anyone share my experience or have I just got a one off
> unreliable Six
> > Pack?
> >
> > 73
> >
> > Bob 5B4AGN, P3F, ZC4ZM
> >
> >
> > _______________________________________________
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> > Towertalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
>
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