On 10/25/2010 7:16 AM, Jim Thomson wrote:
> Who makes 5 x conductor rotor cable ?
Cables designed for communications and control functions like this are
generally pretty expensive, I suspect because they are made in
relatively small quantities.
This is nothing more than an Ohm's law problem combined with the cost of
the cable. When I needed a 350 run from my shack to my Yaesu rotor, I
used two runs of 3-conductor power cable from the shack to the base of
the tower (250 ft), and then found some surplus 8-conductor #18 to go
120 ft up the tower to the rotor. In that multi-conductor cable, I
doubled up on the pairs going to the motor.
Yes, someday the outer PVC jacket of the power cable will rot, but it's
on the ground and easy to pull in, and the multi-pair inside the tower
is protected, sees little UV, and has a much better quality jacket.
In your situation, I would first study what the sensing circuit is. In
the Yaesu rotors, it's nothing more than a 500 ohm pot with DC on it,
and the position indicator in the rotor senses that DC. One end of the
pot is connected to the rotor chassis and to the controller chassis, the
other two conductors go to the top of the pot and the tap. A more
sophisticated controller with a digital readout might still be sensing
that DC. If you think RFI might be an issue, run shielded twisted pair
for that circuit.
73, Jim K9YC
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