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Re: [TowerTalk] Conduit for cables to the tower?

To: "'Alan NV8A'" <>,"'towertalk reflector'" <>
Subject: Re: [TowerTalk] Conduit for cables to the tower?
From: "Mike, K6BR" <>
Date: Wed, 13 Sep 2006 19:31:50 -0700
List-post: <>

I have questions about the best way to get cables (coax, AC, and 
control) from the shack to the tower.

Here are the things I have read or observed and am trying to take into 
account. Please correct me if I am wrong on any point.

1. Low-voltage wiring (e.g., for rotor and other control functions) 
cannot be run in the same conduit as regular power wiring.

** True, I run mine in a separate conduit underground, just makes good sense
to me. 

2. All cables should run in grounded metal conduit for effective 
lightning protection, according to Polyphaser.

** I do not do this, I can not see what difference it would make really, if
I remember, above ground has to be metal and underground can be schedule 40

3. The bends in the conduit for a single run of cable may not exceed 360 
degrees or it becomes too difficult to pull the wires through.

** I would agree, why would you want to anyway?

4. EMT is not buriable. This suggests that RMC must be used, but can it 
be bent? Or can liquid-tight flexible metallic conduit be buried, and 
does it provide sufficient protection? Is there a means of grounding the 
metal in such conduit?

** I hate pulling cable through flexible metallic conduit, I avoid it at all

It looks as though I will need three separate runs of conduit: one for 
the feedlines, one for power for the crank-up, one for the control 
cables and rotator power.

** I run two with no problems, one for AC power and one for coax, control
cable for Steppir and rotator, I have no coupling.  I would add that modern
Yaesu rotators use DC and so does the steppir, so I do not see a problem.

The conduit run for 120V power looks like needing six 90-degree bends 
(two too many), and the other cables eight (double the permitted number).

** Don't know about the code on this, but using 90 degree sweep bends makes
it easier and I think the electrical code requires this anyway, the less the
bends the easier to pull cable, anything more than three and it gets very
difficult.  I would put a ton of talcum powder in the conduit to help.


How have others handled their cabling?


Alan NV8A

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