Date: Sat, 14 Oct 2017 10:08:38 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] rotor @ 200m distance
On 10/14/2017 9:44 AM, Filipe Lopes wrote:
> My question is regarding the rotor, what kind of cable or how should one
> rotate the rotor at such distance? I guess the voltage drop is quite high,
> meaning the rotor will turn very very slowly or even not turn at all.
<Ohm's Law is your friend, but Yaesu's tech data is not. :) They don't
give you a maximum permitted resistance so you must compute it. I have a
350 ft run on my Yaesu rotator. I had to figure conductor resistance for
their maximum recommended cable length based on its conductor size, then
do Ohm's Law with a wire table to know what wire size to use. One
important piece of information -- study the schematic of whatever
rototor you are using. With the Yaesu, two conductors run the motor, the
other three sense the position of a simple potentiometer that tells
direction. Only the motor pair is sensitive to resistance. I ended up
using #14 "house wire" for the motor pair and #18 for the potentiometer.
73, Jim K9YC
## heres another thought. Use the tower as the return. That would work if a
DC
motor was used. Works on cars, and it would work on a tower. But in his
case, the
tower is a long way away, so u still have a V drop from shack to base of
tower.
Jim VE7RF
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