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Re: [TowerTalk] Rotor swap query

To: "Alan Swinger" <awswinger@earthlink.net>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] Rotor swap query
From: "Jim Thomson" <jim.thom@telus.net>
Date: Tue, 18 Nov 2014 05:23:04 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
##  How do you tilt the tower over..with a yagi on top ?
##  Id just extend the tower as required, block it off at the bottom,
then climb it.

Jim  VE7RF

-----Original Message----- From: Alan Swinger
Sent: Tuesday, November 18, 2014 5:11 AM
To: Jim Thomson ; towertalk@contesting.com
Subject: Re: [TowerTalk] Rotor swap query


If your TX-455 nests like my TX-472 does, you will not likely be able to get the rotator out without extending the tower to get access. This is easy when the tower is tilted over (did it this summer), but a different matter with it vertical and extended. Think about getting that Tilt-over fixture.
73, Alan K9MBQ

-----Original Message-----
From: Jim Thomson <jim.thom@telus.net>
Sent: Nov 18, 2014 12:22 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Rotor swap query

Date: Tue, 18 Nov 2014 02:11:06 +0000 (UTC)
From: John McCormick via TowerTalk <towertalk@contesting.com>
To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: [TowerTalk] Rotor swap query

Content-Type: text/plain; charset=UTF-8

It was bound to happen, although I wasn't expecting it so soon. I experienced a rotor issue during the Sweepstakes contest last weekend when a visitor was operating my station in a multi-operator effort. The Ham IV rotor is still working, but the meter dial is stuck at southwest, even when the beam is pointed in another direction. A ham buddy who is much more electrically savvy helped me do some troubleshooting today and we are pretty convinced that the potentiometer up in the rotor is not working properly. We also discovered that the previous owner of the control box had removed the fuse that is supposed to protect the potentiometer and metering circuitry.

The good news: I have a spare Ham IV rotor (purchased for this exact kind of situation), so I can swap them out an make repairs to the one now up in the tower. I also have a spare control box (we tried that as well today and it produced the same southwest reading).

The bad news: I've never swapped out the rotor before and I don't have a gin pole, something I plan to eventually acquire.

My question: What's the best procedure for swapping out the rotor? Will I be able to lift up the mast and beam 18 inches and place it on a wooden brace in the tower, while I make the swap, securing the base of the mast with some ropes or wires to keep it from moving laterally? Am I foolish to even attempt this without a gin pole, helping me lift the weight from the ground?

Some other specifics:

+ US Tower TX-455, with a KF7P work platform installed (cranks down to 22 feet, but I don't have the tilt-over fixture at this point)
+ 5-element yagi (57 pounds)
+ WARC rotatable dipole (about 10 pounds)
+ 10-foot mast, 2-inch diameter (25 pounds)
+ one thrust bearing installed at top of tower

Thanks for any thoughts directly or through the list.
73s, John/N0FCD ( N0FCD@yahoo.com )

## Get the UST MRF....... aka mast raising fixture. I believe it will work on all the ust towers. Then its safe and a snap..to raise the mast up a ft to get the rotor out. I would also temp install a heavy duty clamp around the mast... so it sits on the top bearing. Then its perfectly safe to swap rotors. If you do use a gin pole, it doesn’t have to extend above the top of the tower very high. I would use a cum-along between top of gin pole and mast..just above the top bearing. Either method will work, then its just a case of winching the mast + yagi up 1 foot. Most ust towers have a locking pin to pin the mast..when doing rotor swaps etc, so the mast is not rotating..while doing the rotor swap. Make sure the new rotor is 100% tested good..on the ground.

Jim   VE7RF



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