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Re: [TowerTalk] US Tower RMC-1000 control box question

To: "'Scott McClements'" <kc2pih@gmail.com>, "'Towertalk Reflector'" <towertalk@contesting.com>
Subject: Re: [TowerTalk] US Tower RMC-1000 control box question
From: "Dick Green WC1M" <wc1m@msn.com>
Reply-to: wc1m@msn.com
Date: Sun, 29 Jun 2008 02:34:44 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Scott,

In the stock version of the RMC-1000, the control box has to be connected in
order for the "local" switch on the RMC-1000 to work. The control box POWER
switch must be flipped on, which energizes a 110VAC relay in the RMC-1000
that connects AC to the rest of the circuitry. In addition, the control box
"REMOTE/LOCAL" switch has to be set to LOCAL to enable the switch on the
RMC-1000 housing. I don't remember offhand whether another relay in the
RMC-1000 is involved.

It's certainly possible to modify the RMC-1000 to eliminate the control box,
but you would have to add a couple of switches to duplicate the POWER and
REMOTE/LOCAL switches. These would have to be mounted inside the RMC-1000,
or you would have to drill holes in the housing and use weatherproof
switches like the one that's on the housing now.

Alternatively, you could get away without the switches by hard-wiring the
circuit so the AC relay is always tripped and the local switch is always
enabled.

Either approach, however, would allow anyone passing by to activate the
tower motor. Probably not a good idea.

A better alternative would be to build a small weatherproof enclosure next
to the tower, or even mounted to the RMC-1000, and put the remote control
box in there. You should put a lock on the enclosure.

I operate my MA-770MDP remotely, but I was not happy with the design of the
remote control feature. The control lines are 110VAC, which technically
means they should be run in a conduit separate from all other control wires
and coax. I didn't realize how the system worked until I had already pulled
the control cable through 265' of conduit along with several other
low-voltage control lines.

Rather than live with a an unsafe situation, and a building code violation,
I build a simple 12VDC relay board to exactly duplicate the action of the
remote control box switches. I mounted it inside the RMC-1000 and built a
12VDC control box which is about 1/6 the size of the AC control box. It has
the same set of switches as the original box: power, raising/lowering, and
local/remote. These simply switch 12VAC relays in the RMC-1000, which in
turn switch 110VAC to the big stock relays in the RMC-1000. The status light
voltages from the RMC-1000 activate 110VAC relays on the board I added to
the RMC-1000. Those relays switch 12VDC to LEDs mounted in my low-voltage
control box.

73, Dick WC1M

> -----Original Message-----
> From: Scott McClements [mailto:kc2pih@gmail.com]
> Sent: Thursday, June 26, 2008 9:36 PM
> To: Towertalk Reflector
> Subject: [TowerTalk] US Tower RMC-1000 control box question
> 
> Hi All,
> 
> I am just starting to do some refurb on a used 1992 US Tower HDX572 I
> bought. It has the RMC-1000 remote option. I  The tower is on stands
> right now. I took off the drive belt and without any remote control
> box hooked up, I plugged the tower into AC  locally at the tower. I
> flipped the switch to both raise and lower the tower and the motor
> didn't start up or even make a sound. I have a few documents from
> various about the RMC-1000 circuit in both the remote control box and
> in the local control box. I started to draw up a schematic for myself
> too. I am running a heavy extension cord directly to my service
> entrance on a 20 AMP circuit.
> 
> Now a few questions. Does the remote box need to be hooked up to run
> the local controls? If so, can I bypass that, because I don't plan on
> using the remote option. If it should have worked as, where should I
> start on this. I did some basic checks with a volt meter, power is
> getting to the terminals. I checked the 20 AMP fuse while it was in
> the holder. It appears ok, but maybe I should pull it out of the
> holder. I don't know what to look for next.
> 
> Here is a picture of the 1992 vintage innards :
> 
> http://picasaweb.google.com/mcclements/HDX572/photo#520478827723580865
> 8
> 
> Any and all suggestions appreciated.
> 
> -Scott, WU2X


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