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Re: [TowerTalk] Rotor Cabling Query

To: "tower >> [TowerTalk]" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Rotor Cabling Query
From: "Joe Subich, W4TV" <lists@subich.com>
Date: Fri, 2 Apr 2021 19:53:53 -0400
List-post: <mailto:towertalk@contesting.com>

A primary point/concern of my post is the length of the run on the temporary 300 ft and to the final goal of 700 ft. What size of the conductors/wire/cable to utilize for the effort. Some part being
heavy duty 8 conductor rotor cabling in conjuction with splices
and/or runs of UF solid wire cabling from 14 gauge to 10 gauge such
as 14/3, etc. or other such ideas on conductor size.
You will need to figure out those trade-offs for yourself in your
particular installation.

The brake solenoid in the Ham IV/T2X is rated 24 VAC @ 5A.  The brake
uses wires 1 and 2 (the "heavy" wires).

The motor in the Ham IV/T2X is rated 20 VA @ 2.25 A.  The motor uses
wires 4, 5, 6, and 8 plus wire 1.  Rotation power is supplied to either
5 (rotate right) or 6 (rotate left).  4 and 8 are the capacitor
connection and the return in wire 1.

To energize the brake you have the voltage drop of (0.75 Ohm + the
resistance of wires 1 and 8) x 5 A.  To turn the motor you need to
overcome the voltage drop of (5.0 Ohms + wire 5 or 6 + wire 4 +
wire 8 plus wire 1) x 2.25 A.

I do not know how much voltage sag the brake or motor can handle before
they stop working reliably but I would not allow more than 2V drop as
a first estimate.

The typical "light duty" eight wire rotator cable is 2 x #18, 6 x #22.
DX Engineering says "suitable for most controller to rotator cable
runs of less than 125 feet."  You could probably back out the voltage
drops for a 100' run and use that as a "safe" limit.   The so called
"heavy duty" rotator cable is 2 x 16, 6 x 18 but is probably marginal
at 300 feet.


73,

   ... Joe, W4TV


On 2021-04-02 7:10 PM, CEPitts wrote:
I would like to hear from those in regards to ideas for the following. I know there are those who have long runs of control cabling for rotation, switching, etc. so I seek your ideas and advice.

I have a need for a temporary set up of a run that is 300 feet from the operating position shack/controller to the top of the tower controlling a Ham 4 rotator. The final set up with be a run of 700 feet from tower to the operating position shack/controller

Would it be best to provide a disconnect near the connection point at the top of the tower with a short pigtail to the Ham 4, as well as a disconnect/splice point at the bottom of the tower, and a final run to the shack/controller?

Based on previous discussions/ideas tossed around here within the last 2-3 weeks I would most likely take some ideas from the group in regards to utlizing trailer type connects/disconnects and also splices within the entire run.

A primary point/concern of my post is the length of the run on the temporary 300 ft and to the final goal of 700 ft. What size of the conductors/wire/cable to utilize for the effort. Some part being heavy duty 8 conductor rotor cabling in conjuction with splices and/or runs of UF solid wire cabling from 14 gauge to 10 gauge such as 14/3, etc. or other such ideas on conductor size. A reasonable cost/maintenance perspective would be ideal keeping in mind going from the 300 ft to the 700 ft in the future and ease of said transistion. None of this will be buried, I have that part taken care of.

*(tower/rotor)*****short pigtail/run-->>>---*****(pigtail/connect splice)*****run to bottom of tower -->>>-->>>-----*** **(bottom of tower/connect splice) *****--->>>---->>>---*-****temp run*****>>---->>>>>>>---->>>>>>----->>>>>>>------>>>>>------->>>>> 300 ft expanding to 700 ft>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> (later to be the permanent run)>>>>>>>>>>>>>>*** **to connect/splice back to 8 conductor rotor cable ham 4 controller in shack.****

Besides possibly utilizing trailer type connects/disconnects I was also considering utilizing 8-10 conductor terminal blocks for splices/junctions etc. and I could possibly place those in weather resistant boxes at those points where required....What is the thought on that approach?**

Thank you for all the input/ideas and73! Ed K5OF in NC

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