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[TowerTalk] Switching 450 ohm twinlead?

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Subject: [TowerTalk] Switching 450 ohm twinlead?
From: (Larry Lindblom-wa0etc)
Date: Sat, 07 Jun 1997 09:55:14 -0700
Jim Reid wrote:
> At 09:27 PM 6/6/97 -0400, L. B. Cebik wrote:
> >Henry,
> >
> >Unless you are using a matched 450-ohm load to 450-ohm lead, the impedance
> >bumps created by relay spacing will be in almost all instances meaningless
> >and minor, with no consequences for efficiency/loss of the power transfer.
> >
> >
> >Also, be sure that the relays can handle the high humidity that will
> >inevitably be present in the remote box.  Corrosion does not require
> >direct contact with rain drops.
> Loyd Colvin,  in his 8/56 QST article,  suggests leaving a small
> voltage on the relay coils.  This to provide a bit of heat to
> drive the moisutre away.  Wonder if it really works,  I will try
> with my set up.  Plan to use a Radio Shack enclosure for the
> relays/450 ohm lead/V-beam wire connection.  Guess will use a
> metal box rather than the plasic ones.  Must find some feed-thrus
> to mount/terminate wires.
> 73,  Jim, KH7M
> --
> Jim, some of the commercial relay boxes claim the include a heating element 
> to reduce moisture build up.  When opened up the heater is a 10 watt wire 
> round resistor.
73, Larry L.

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