I have 8 towers, with rotor cable runs up to 700 feet or so. Rotors are
HyGain/CDE T2X, Ham 4 and M-Squared OR2800.
Most of my rotor cables have been "scrounged" from salvage yards and other
sources. Telephone cable, computer cable, old RG8 coax -- I've even used
1/2" CATV hardline for rotor cable. Very few pieces are true "rotor cable."
One uses 24-conductor computer cable, with multiple conductors of No. 24 or
so paralleled to carry sufficient current. Few are continuous -- I use small
terminal blocks on a pipe or wood post a foot or two above ground, covered
with a plastic bottle for weatherproofing, to make a splice. Have never had
a failure at these points (22 years+), even in my wetlands environment.
Cables are laid on ground through the woods.
With multiple sections of cable, wire colors may not always match. Some may
have 2-3 changes along the way. Documentation is important for future
reference.
If buying new, consider sprinkler cable available at the big boxes.
I have 6-10 volt boost transformers in series with the brake transformer in
the HyGain controllers on a couple of the long runs. 8-10 amp capacity
needed. These are mounted on the rear of the rotor controller.
I put the rotor capacitor in a small box at the base of the tower, so those
two wires are not running all the way to the shack. If you put it at the
rotor, the capacitor will fail in the worst of weather (been there!).
Breaking the cable with a terminal strip in this box at the base of tower
also provides a handy access point for testing to debug rotor or cable
problems, and to measure for voltage drop on the long run to the shack.
When I have a rotor rebuilt, it gets a simple pigtail of 3-4 feet of rotor
cable through a feedthrough where the old terminal strip (on HyGain/CDE) was
located. Then connections are made with a small barrier strip inside a
4x4x2" Carlon weatherproof box (about $10 at the big boxes) mounted near the
rotor. I find this much more convenient to work on at eye level than dealing
with the terminal strip under the rotor (especially on bright sunny days).
And cheaper than a weatherproof connector that is difficult to replace atop
a tower.
73/Jon
Jon P. Zaimes, AA1K
Tower climber for hire
http://www.aa1k.us/
Cell: 302-632-2353
Reviews of AA1K tower work on eham website:
http://www.eham.net/reviews/detail/12922
Hug your favorite tower every day, and always stay connected to it.
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of Joe Subich,
W4TV
Sent: Saturday, April 3, 2021 10:08 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Rotator Query
On 2021-04-03 9:02 AM, Wilson Lamb wrote:
>
> If you find the right contractor, you can get control transformers out
> of old air conditioning units, usually 120V to 28V,
Depends on the current rating of the surplus transformers. You would need
at least 5A on the low voltage side. Given the dual winding nature of the
Hy-Gain rotors you would also need *six* transformers (two for the brake
(1/2), two to rotate CW (5/1), and two to rotate CCW (6/1)). The motor run
capacitor (4/8) would need to be relocated to the tower.
The other option is to use one pair of 8A transformers (step up/step
down) on wires 1/2 (brake and motor common) and a couple of 24 VAC relays
(at the tower) to control rotation (again with the motor run capacitor
relocated to the tower).
In either case, be careful to bring wire 1 back unbroken as it is also used
for the direction indication.
Years ago the solution for Hy-Gain rotors was to use a surplus 5 - 6.3V
(filament) transformer to "boost" the 24-26V. Connect the primary of the
additional transformer in parallel with the primary of motor/brake
transformer and connect the secondary in series with the "ground" lead from
the brake transformer secondary to terminal 1 (common to motor and brake).
Make sure to check the brake voltage for boost instead of buck!
73,
... Joe, W4TV
On 2021-04-03 9:02 AM, Wilson Lamb wrote:
>
> How about using transformers to raise the voltage for the long run and
again at the tower, to go back down.
> You could use at least 120V, but likely even 240V.
> If you find the right contractor, you can get control transformers out
> of old air conditioning units, usually 120V to 28V, They often show up at
hamfests too.
> Wilson
> W4BOH
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