I sent an e-mail directly to the original poster on this subject. What I
mentioned to him is that AlfaSpid has a circuit in there manual which allows
the use of their rotor at very long distances. It involves using a DC power
supply at the tower and a relay board to use the voltages from the in shack
control box to apply the PS voltage to the rotor motor. The data lines
should not be a problem at longer lengths. This of course requires that you
have 120 or 220VAC at the tower site.
Julio, W4HY
-----Original Message-----
From: jimlux [mailto:jimlux@earthlink.net]
Sent: Wednesday, January 14, 2009 9:46 AM
To: donovanf@starpower.net
Cc: towertalk@contesting.com; aredandgold@msn.com
Subject: Re: [TowerTalk] Rotor control
donovanf@starpower.net wrote:
> Lee,
>
> There isn't anything especially difficult about controlling a rotator at a
distance of 750 feet. The only issue is maintaining the required voltage
for the motor, and the brake if the rotator has one. That distance presents
no problem at all for indicator circuits.
>
> I currently have two M2 Orion rotators that are over 700 feet from their
control boxes, and there is no problem at all. This rotator requires only
four wires: two for the motor and two for the indicator circuit. I use #10
wire for the motor. Although I use #12 wire for the indicator, smaller wire
would work well.
>
> The motor and brake voltage for the Ham4 and T2X rotators are more
critical. Again, the indicator circuit is not a problem with these
rotators. The following techniques will allow a Ham4 or T2X rotator at
operate 750 feet from its control box:
> 1. Three #10 wires from the control box (the motor and brake wires,
terminal strip wires 1,2 and 3)
> 2. Relocate the motor starting capacitor to a convenient much closer to
the rotator. Its not necessary to place it immediately next to the rotator.
> 3. Mount a small transformer on the back of the control box and wire
it into the control box to boost only the brake voltage.
>
> 73
> Frank
> W3LPL
>
2100 feet of AWG10 wire is going to be pretty pricey. Seem to recall
something like $80/500 ft, so you're looking at over $200 just for the
wire. (although copper prices are always changing)..
I like the idea of just using a transformer to boost the voltage to
overcome the additional drop from more reasonably sized wires. The
money you save on the thinner wire would cover the cost of the
boost/buck transformer.
(Unless there's a widely varying load and an overvoltage issue..)
Jim,W6RMK
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