The telephone company does this, too. It's called "sealing current" but
they use a larger voltage than 'a few volts'. This does
not have to be continuously applied. I think modern telephone central offices
apply sealing current to each loop once every two or
three days now, and not at all if the phone has been rung recently (since
ringing voltage accomplishes the same thing).
-----Original Message-----
From: topband-admin@contesting.com
[mailto:topband-admin@contesting.com]On Behalf Of Greg - ZL3IX
Sent: 2002 October 24 Thu 02:06
To: Topband Reflector
Subject: Re: Topband: Use of the RCS-4 for Remote Beverages?
> > Part of my idea is to run coax out to the center of the field, and
> > then use an Ameritron RCS-4 remote switch as the center hub.
>
> The newer version of the RCS-4 should be better at switching receive-
> only signals. It now uses fully sealed relays which are more immune
> to contact contamination.
>
> The older open-frame relays were OK if you transmitted through them
> on occasion, but probably are not a good idea in receive only
> application. The new boxes have the connectors in a rectangular
> layout, rather than in a line.
>
Hi Tom et al,
A trick I learned from a relay manufacturer a few years back, is to put some
DC on the lines being switched. Just a couple of mA from a few volts is
enough. It seems that the micro arcs formed when the contacts open and
close are sufficient to keep the contacts low resistance.
73, Greg, ZL3IX
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