Rotator Questions and Comments


 Since I've had the website information on repairing, rebuilding, and renovating rotators, I've received several emails from other hams.   I'm certainly no expert but I answered them to the best of my knowledge.  The following page shows some of these emails and the answers I gave them to their questions.   Perhaps these can help others.

#1.

NOTE:  This person had written to ask me about a model TR-2C antenna rotator, a real oldie.  This was my answer back to him:

Subject: Re: Thank you for the ....

Date sent:            Wed, 06 Feb 2008 16:08:33 -0600

 Hi Darrell --

Thanks for your note.

 My dealings with CDE rotators go back to the 60s and I don't remember a TR-2C.  My first rotator was a TR-44 and I know it was an upgrade to their TR-4.  I don't know if the TR-2C was the model even before the TR-4 or it might have been a predecessor to the AR-22 which was smaller than the TR-4/TR-44/TR-45 series.

 CDE was very good about using duplicate parts in their units and the larger model just had more parts, i.e., additional bearings, additional whole bearing races, etc.    One unknown feature of the TR-44, and perhaps those earlier models, was a gravity brake.  I don't think they ever advertised it as such but the top part of the motor armature was attached to a round piece of clutch material which rotated with the armature.  When there was no power to the motor, that piece of clutch material rested on another stationery piece of the same type of material.  This kept the motor from turning and windmilling in the wind.   When power was applied to the motor, it hopped up just a bit and rotated in the raised position.  When power was removed, gravity caused it to drop back down and the clutch material held it from rotation.  It wasn't nearly as secure as the mechanical wedge brake used in the Ham-M, Ham-II, etc. series but it did hold somewhat.

  I first discovered this interesting brake when I had a TR-44 rotator turning a Hornet TB-750 beam on my first tower which was a homebrew 55 foot model.  The tower consisted of two 30 foot pieces where the inner section telescoped inside the larger outer section and overlapped five feet at the middle.  I would always crank the inner section down all the way and then crank both sections over so I could work on the antennas on the ground.  One time, while cranking the tower over, as the two sections were being cranked over, they reached approximately a 45 degree angle and suddenly the rotator and beam began to turn and didn’t stop until the heaviest part, the reflector element, was parallel to the ground.  I thought at first that the rotator had somehow broken because I’d never seen it allow the beam to move around in normal use.

 After some later experimentation, by leaving the beam in any position except one where the reflector was parallel to the ground, it would suddenly begin to turn, with a small whining sound, until the reflector returned to its desired position.  Several years later, when I took the rotor apart for replace the direction indicating rheostat, I looked the motor over carefully.  It was obvious, with the armature which could move up and down and with the clutch materials at the top, that CDE had made the TR-44 with a simple mechanical brake.  For that brake to work, however, the rotator had to be mounted up and down as in a normal installation.   Once it got off its vertical mount, gravity could no longer hold it from moving and it could then reverse rotate, hence the windmilling.  Fortunately for me, that gravity brake was sufficient for the Hornet antenna that I had.

 As far as repairs on your rotor, if I were you I would take lots of photographs and then go to one of the larger hamfests in your area.  If MFJ comes to your hamfest they usually bring with them a good supply of the CDE/HyGain/MFJ rotator parts.  If you've got some good pictures, I'll bet the guys at the MFJ display booth can help you.  Come to think about it, you're there in LA with MS next door...... perhaps you're within driving distance of the factory.

I've been surprised at all the good responses I've received from readers.  Seems like information on ham rotator repairs should be all over the Internet but it's been pretty scarce so I'm glad I took the time to write it.   Actually, the rotor I was rebuilding in the article has now replaced my Tail-Twister on my biggest tower so the TT is now down and waiting for me to do a complete rebuild on it.  I haven't quite worked up the energy to do that but it's a "soon to be done" project.  When I do, I'll take lots of pictures and write up a sequel with it.

 Lastly, if the motor still turns, the electrical connections can still be made, the case can still be securely held together and the mounting pieces are still in good shape, you should be able to rebuild this one and get some good use from it.  Age alone, doesn't always make something bad.  (Hmmm.... I just had a birthday.......... let me see if what I'm writing you is about rotators or something else....)  Anyway, good luck on your project.  I hope this has given you some ideas and some help.

73,

 Jim - K5LAD


#2.

HI JIM

DISREGARD MY LAST EMAIL, THE SEND WAS CLICKED BEFORE I FINISHED. I TOOK THE ROTER BACK APART AND FOUND MY PROBLEM WITH THE BOTTOM ISSUES. THE NEW PROBLEM MY ROTOR WILL ONLY GO IN ONE DIRECTION I DID NOT MARKED IT BEFORE STARTING.  I CHANGED THE TERMINAL STRIP 1-8, REWIRING IT; THE ROTOR HAD A LOT OF RUST SO I CHANGED RUSTED PARTS ALSO. EVERY THING WAS WORKING FINE BEFORE I WORKED ON IT (SMILE).

 I HAD THE ROTOR AND ANTENNA TAKEN DOWN TO CHANG ANTENNA, THE PERSON TAKING IT DOWN BROKE 2 BOLT IN THE BOTTOM SO I TOOK IT APART TO GET THE BOLT OUT. THE ROTOR HAS A LOT OF RUST SO I CLEANED IT CHANGED ALL RUSTED PARTS. NEW PROBLEM THE METER DOES NOT APPEAR TO INDOCATE OR MOVE, ROTOR WILL GO ONLY IN ONE DIRECTION. THANKS FOR ANY HELP!

 BILL    KA4---

-----Original Message-----

Sent: Wednesday, December 19, 2007 2:01 PM

To: Bill

Subject: Re: HAM 4 PROBLEM

 Hi Bill --

I don't think you're going to like my answer.  That answer is:  To keep from having the bottom not fit when the rotor is reassembled, you must mark the pieces BEFORE you take it apart.  My experience has been, it will always go back together correctly if it's reassembled the same way it came apart. 

Now, what can you do if you didn't mark it first?  The only thing I can tell you is -- try it and if it doesn't fit, take it back off, move to a different location and try again. 

Also, as I mentioned in my article, the plastic bearing holders must be in correctly.  If they're inserted upside down, the bottom won't fit on.   It actually looks the the clearance is the same either way but that's not been my experience.  I don't recall which side is which but I believe I described that in the article.

 Like I said, you won't like that answer but it's the best I can come up with.  It's trial and error if the outer shell pieces aren't marked.

 I hope the article did help you, at least partly and good luck on finishing the project.

Merry Christmas and 73,

Jim - K5LAD


#3.

Hi Chris --

I learned a lot of interesting things when I owned a ham store back in the 70s.  I sold a lot of CDE rotators during that time and one thing I learned was that the TR-44 has a "gravity brake".  I couldn't see it in your pictures but I recall that the armature of the TR-44 had a piece of clutch material at the top, which rotated with the armature and faced down.  Another piece was on top of the motor facing up.  When power is applied to the motor, the armature hops up just a bit which allows it to rotate.  When power is removed, gravity pulls the armature back down and the two pieces of the clutch material held the armature from turning.

When the rotator was mounted in a tower that could be cranked over, when the tower reached about a 45 degree angle, if you had a very large beam attached it would suddenly rotate (windmill) to the heavy side down when the gravity brake materials separated.  As far as I know the Ham M-IV series did not have that same thing since they had the mechanical wedge-type brake. 

Perhaps yours has a different problem but I thought that information might help.

Good luck and 73,

Jim - K5LAD


On 16 Nov 2007 at 18:31, xxxxxxxxx wrote:

 I have a rotor that has the letters TR 44 SER2 345 on the bottom.  I  have cleaned all the gears and moving parts inside and greased them. However, I can't get the motor to spin.   I am pretty sure the wires are too corroded to make good contact.  I should have checked that before I put it back together.  Now I don't have the motivation to do anything more with it.  Photos of the rotor can be seen here...

http://hrrdb.com/stuff/

  there are photos of other projects too, just ignore those.

The control box is a CDE model H-III/CD-44

 you can contact me using the contact form on the website home page or by phone ###-####

Chris W  KE5---


#4.

On 26 May 2007 at 7:25, John wrote: Hello Jim

 Just got done reading your article on repairing the CDE rotors, I  just rebuilt my Ham III with new  parts I acquired at the Dayton hamfest which included the new "pot".  Everything went well, except the "pot" will not indicate movement on the meter on the control unit, even though I can use my multimeter to watch the "pot" value change when the rotor is moving, which would indicate to me that the copper contact is seated in the top of the top bell.

 I wonder if you could give me insight into what the possible cause  could be for this. I have checked the continuity clear inside the control box so this would eliminate the screw connectors, and I have checked my wiring several times so I don't think it's that.

 Thank you

John W8ZL

 

Hi John -

That's a bummer. 

 If you're seeing the pot change value on your multimeter when you measure at the rotor, then that would pretty much rule out the pot itself.  If you checked it at the end of the rotor cable (on the ground) then the cable must be OK.   That pretty much leaves the problem in the control box.

 If you could find a junkbox 500 ohm pot you could temporarily wire it across the proper terminals on the box and see if the meter is following the movement of that pot properly.   I think even a regular old carbon type pot would be OK since I don't recall there being too much current through it.  That's with the rotor not even being connected to the box at all, just extra pot to screw terminals on back of the control box.  When you swing it around, the meter should indicate.  You may have to hold down the control box switch to provide voltage for the meter circuit.

 It may be one of those things where you're overlooking a miswiring error because you are too close to the problem.  If you've got a buddy who can look at the situation, he may see something that you missed.

 I just come back to the fact that if your multimeter is indicating movement from the pot then the pot is not the problem.  That's about the best I can do from this distance.  Let me know the solution when you locate it.  Good luck on your project and 73,

 Jim - K5LAD


#5.

On 15 Feb 2008 at 12:02, jerry b------ wrote:

Hi-liked yr artical on the rotor repair.was hoping to find one on the indecater part of it also. Mine is sitting on the left hand side of the meter. Guess there isn't much that could need to be changed. Blows the 1/8 amp fuse. Tks for the fine artical. de Jerry W8--

----------------------------------------------------------------

Hi Jerry --

Thanks for the comment on the rotator repair article.   I hope it provided some help for you.   As far as your other problem, I might be able to give you some clues but I do need more information.   What type rotator are you using?  If it is a CDE/HyGain unit, which model do you have?  If I read your note correctly, I think you're saying that the fuse won't stay on and the meter is not indicating. Can you give me a little more information? 73, Jim - K5LAD

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On 15 Feb 2008 at 12:45, Gerald B-------- wrote:

Hi- HyGain 4 -Everything in manual on checking it out ,says meter hard to the right hand side.Mine is to the left. All res.seem to be ok,with wires off.Then a new fuse don't blow. Don't see much DC after the rec.diode. Going to change that and then the zener diode. The 2 res.seem about right.Later,Jerry

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OK, I'm looking at a schematic of the control box for the Ham IV.   The meter will only be to the right when current flows through that meter so if it's resting on the left side, no current is flowing. Now lets see how that could happen.

1. Fuse is blown - this could be caused by a grounding short on pin 3 of the controller. It could also be caused by a grounding short on the output side of the fuse block. That's the one where a 10K resistor is connected.  If the fuse is still blowing, remove it and measure with an ohmmeter from the output side of the fuse block to ground. What is the value?

2. Failure of the simple power supply for the indicator. Make sure you see 13 volts on both sides of the fuse block when you have a good 1/8 amp fuse installed.   Don't see much DC after the rec.diode. Going to change that and then the zener diode. What does "don't see much DC" mean? Do you see any at all? How much? If you're not seeing any DC voltage past the diode, are you measuring any AC voltage from the meter transformer? Actually, if you're getting any AC voltage from that transformer, the bulb should be lighted --- is it? Is it dim or fully lighted?

More questions but the solution is hidden within the answers to those questions. Be sure you answer each one. 73, Jim - K5LAD

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On 15 Feb 2008 at 13:32, Gerald B------- wrote:

Hi- Little dc .5-1 volt- Ac-4-5 Res. seem the right res. All the checks in the book are with the wires off. They seem fine,Lamp is ok - light! .Have to get back to it tonight .Had snow to take care of. Rotor turns FB,No indicate ! -Later,Jerry W8--

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OK Gerald --

Sounds like a possible bad diode. I am concerned that you said you had light but the AC measures 4-5 (volts). The bulb in that unit is a #1819 and that's a 28 volt, 400 ma bulb. If there's only 4-5 volts across it, if it lights at all it should just barely be lit.  Is this a new unit or old? Did the meter originally indicate? This would tell us if the meter movement itself is defective. Also, if the voltages get up to their correct values, I'd want to be sure that the 5K calibration pot on the front panel is not open.

Enjoy your snow. If I can help you further, let me know.

73, Jim - K5LAD

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On 16 Feb 2008 at 11:10, Gerald B------- wrote:

Hi- GM- I got it.Was a bad diode.Had a Moto 170- wouldn't think that would go.Think they are 1000prv and 2.5 amps.Oh well.See what a new one does. Sure hate to get into stuff these days . Most get sent in.TKS,For yr help

De Jerry W8--

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OK Jerry --

That was an easy fix, once you determined what was the problem. I'm glad it wasn't the meter movement itself....... that would have been a show-stopper.

Good luck with your new repaired rotator and 73,

Jim - K5LAD

 

#6.


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Created April 12, 2008      The page was updated on 04/12/08 11:42 PM

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