[TowerTalk] Rotor Cabling Query

[Lux, Jim]

On 4/2/21 4:10 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
>
> _______________________________________________
>
>
>
I'm moving to an RF link (WiFi or long range serial) and just sending 
raw power out. You can run pretty small wire and use a boost transformer 
to overcome the voltage loss.  Put your rotator controller in a 
weatherproof box at the tower.


The brake draws 5A @ 24V according to the manual. You probably need 20V 
or so minimum, so for 1400 ft (out and back), to keep the voltage drop 
at 6V from the usual 26V transformer, the resistance has to be less than 
about an ohm.  AWG10 is 1 ohm/1000 ft.  So you'd need what, AWG 8? 
That's a pretty substantial expense.

The manual calls for AWG14 for 300 ft. You're running more than twice 
that, so to keep the resistance the same, you need to go down 3 gauges 
(3 gauges is twice the area/half the resistance). They call out AWG16 
for most of the other wires than the common and brake. (The motor draws 
2.25A)


Someone probably makes a suitable interface (Green Heron?).





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