The cautions that you have received are very real potential problems when
motorizing a crank-up tower. Although I have not worked with the Tri-Ex WT
series, I have motorized, and remote controlled several Tri-EX LM-470 towers,
and currently have a US Tower HD-589 that has the remote feature.
The RMC-1000 controller is a US Tower item, and is nothing more than a
grouping of switches and indicator lights for power on, Remote/Local, Tower UP
Tower Down. It does not supply power to operate the winch motor, but does
control a remote relay that does activate the remote control box at the tower.
That box contains relays for UP and DWN (reverses the motor rotation), two
time delay relays to prevent switching direction too quickly (if you don't
delay, the motor keeps going in the same direction). and also interfaces with
UP and DWN limit switches.
One key issue is the winch type and drum size. The type should be worm gear
driven, a ratio of about 40:1, The drum size in the 3 to 4 inch diameter,
and the length must be capable of hold all the cable in ONE single layer. You
can not jumble wind cable when using a positive pull down cable. You do need
a long eyebolt with a very heavy coil spring of at least 8 to 10 inches long
(a 51 foot tower may get away with less). This spring maintains positive
tension on the down cable, and compensates for the normal stretch or give in
The amount of UP cable that spool onto the drum is a function of the lift
cable design - Late model LM-470 towers this cable went to the top of the base
section, down to the bottom of the first moveable section, and then back to
the top of the base section. This is a two to one mechanical advantage, and
the amount of cable winding onto the drum is double the length that the first
From: "Bill Kerns" <email@example.com>
Subject: [TowerTalk] Tri-Ex WT-51 Electric Winch with Pulldown
Mechanism and RMC-1000
Content-Type: text/plain; charset="us-ascii"
I recently purchased a used Tri-Ex WT-51 tower with manual winch.
I want to install an electric winch on the tower to allow me to raise and
Since the tower will be located remotely from the house (about 200-300
feet), I'd also like to figure out a way to raise and lower it remotely.
I have also found a used RMC-1000 remote controller and am considering using
it in conjunction with an electric winch.
However, I have heard that there is a pulldown safety issue involved with
this tower. So I need to have a way to pull down the top antenna tower
sections, as the tower is being lowered, to ensure that it does not get hung
up on the way down. My understanding is that the WT-51 top sections may
sometimes bind on the way down, so having this second cable pulldown
mechanism will prevent that.
I am considering a single winch with 2 cables wound in opposite directions,
so that as one cable winds up, the other cable unwinds. Then I need to add
some pulleys to route the second cable through the middle of tower up to the
top section, so that when the tower is lowered, this cable will pull down
the top section as the other cable releases. However, someone said that
this might be problematic, since the 2 different cables may not wind/unwind
at the same rate, so I also will need a spring mechanism to take up the
slack as the cable winds/unwinds.
I would appreciate whatever advice anyone could provide to help with this
installation- such as recommended electric winch model part numbers,
suggested ideas for using RMC-1000 or similar remote system, pulley layout,
etc. I also wonder what the maximum distance is that the RMC-1000 will
operate remotely, since there will be 200-300 foot separation between the
house and antenna tower.
I am also looking for a softcopy of the RMC-1000 schematic and manual, if
anyone has one.
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