[TowerTalk] Resistance of Rotor Control Wires (see also CAT5 thread)

[Jim Brown]

On 7/26/2012 2:44 PM, Larry Loen wrote:
> I am trying to understand control wire (DC) resistance losses.

You're right to be concerned -- CAT5 is far too small for your needs. 
But it's simple Ohm's Law, and you compute the IR drop for 2X the length 
of the cable, looking up the R for various wire gauges from a standard 
wire gauge table.  To make that computation you need to know the current 
that the rotor draws or the resistance of the rotor. You also need to 
know how much IR drop the rotor can tolerate and still have good torque.

I don't know what an "M2" is so I can't help with that.

Some rotor mfrs are better than others about providing this info in a 
useful form.  For example, Yaesu gives max distances for a certain wire 
gauge, and you need to do the arithmetic to translate that to greater 
distance and larger wire gauge.  A simple rule to remember is that three 
wire gauges is double or half the resistance.

73, Jim K9YC