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Saving Money On Rotors

from Steve Fetter, WA8UEG on April 10, 2017
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Saving Money On Rotors
By Steve Fetter, WA8UEG

Putting up an antenna system can be an expensive endeavor. The cost of beams, towers, masts and rotors can add up to big bucks even if purchased used. One way to save money and still have a modern, up to date, rotor system is to buy used and update/rebuild.

In October of 2013 I published an article here on how to rebuild a CD45II and similar HyGain rotors. Shortly I plan on improving the article by including the Ham IV and T2X with more detail then the previous article. The basic rebuild of all 3 are very similar the CD45 does not have a break, uses half the bearings of a Ham IV and while the CD45 and Ham IV use 2 sets of bearings the T2X has 3 sets. The gears and motor for both the Ham IV and T2X are more robust as well. A new Ham IV is around $650 without a controller capable of RS232 or USB connection to a logging or computer program.

The good news is you can buy a used Ham IV for under $200 and if your patient in your search a lot less.

You would never want to put a used rotor into service without opening it up and evaluating itís condition. The main thing to look for in a used rotor is to make sure the Motor is working, in the case of a Ham IV or T2X a good hard clicking sound when stopped is a plus and indicates the brake mechanism is working. Another plus is if the control indicator make a full rotation smoothly without any major jumping movement on the meter indicating the rotation potentiometer and gears are either ok or serviceable. The pictures below are of a T2X that was stored for several years, I was told it was in excellent working condition but convinced my friend to let me take a look before he installed it on his 70í tower (he was glad I did) and a Ham IV I recently purchased. This ham told me he had taken the Ham IV completely apart, cleaned all the bearings and gears, set for north center rotation and tested, ďready to put into serviceĒ. Point is donít ever place a used rotor into service without first popping the hood and taking a look. If not you could be installing a rotor that looks like the one below! (before & after)

Below is the T2X - A good sanding and paint job along with SS bolts, nuts and lock washers gets it back to looking new.

The bearings were badly pitted and rusted , 4 were missing. Main and drive gears had sticky thick grease and brake housing rusted.

Parts are reasonable and easy to get, most rotors can be rebuilt for under $50.00 and no special tools are needed. The indicator pot is $40 if needed but most can be cleaned and reused, of course if the motor or brake assembly needs replaced the cost of the repair goes up but that is the exception not the rule even for rotors in bad shape. You can get an idea of parts cost by going to the Hygain web site and the rotor you are interested in, all the parts and prices are listed there.

Now for the control box. If your buying a used rotor chances are (about 100%) it will not have the brake delay or any other features. I use to hate going from 160 degrees around to 320 degrees with a Hy Gain control box. If your using a Ham IV or a T2X the correct procedure is to hold the brake paddle along with the direction paddle down then when the position you want is reached release the direction paddle first, let it coast to a stop then release the brake paddle. Yea right, Iím sure everyone does that!

For a fraction of the price of a DCU control box or other upgraded boxes Hy Gain control can be brought into the 21st century. This easy to install mod gives you end of rotation protection, normal or point and shoot control (turn what was the calibration pot to the heading you want then press the brake paddle momentarily and it turns to the heading hands free), jogs the rotor in the opposite direction momentarily before turning to the desired direction to free the brake, can give you a 90 degree offset by flipping a switch if you have a staked array with an antenna at 90 degrees to the main antenna, cuts the motor and allows the rotor to coast to the desired direction before engaging the brake. Now, I said it's an easy installation and it is for anyone with some basic skills. Older control boxes require adding some LEDís as indicators for direction (like the new units have) and a nifty light that changes colors as you approach the desired direction so some careful drilling of the front panel is required as well as basic soldering skill on a PC board. You can get it with or without RS232 control, assembled and tested or in kit form, a USB converter cable with the necessary software. They also have a LED kit to illuminate the meter that is a 30 minute project start to finish. Information can be found at

New a Ham IV with the DCU control unit is around $800.00 but by rebuilding one and updating the control box you should be able to have just as good and just as reliable system for less then 1/2 the price. The only thing missing would be a digital readout.

Member Comments:
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Saving Money On Rotors  
by K9MHZ on April 10, 2017 Mail this to a friend!
Wow, that thing looked terrible. Good on 'ya, Steve. That's a nice restoration.
RE: Saving Money On Rotors  
by AF6AU on April 10, 2017 Mail this to a friend!
Yep. I have seen this before, usually, it's a "Box Special Good Working Rotor", yeah, sure thing...

3 notables...




Done right, and chances are the next work needed will be replacing the wiring the sun has destroyed after many years, and not a seized up Rotor.

Saving Money On Rotors  
by KB9FMV on April 10, 2017 Mail this to a friend!
Great Article ! EXCELLENT INFO !

RE: Saving Money On Rotors  
by WA8UEG on April 10, 2017 Mail this to a friend!

If anyone is interested here is the link to the first step by step rebuilding of a CD45II. I am currently working on a more detailed rebuild article for both the Ham IV & T2X.

You can copy and paste or right click on it then click go to article.
Saving Money On Rotors  
by AE7IS on April 10, 2017 Mail this to a friend!
i would really like to know where you got your "pot" for 40 bucks? Mine from Normʻs cost me close to 100. yes same model I believe.
RE: Saving Money On Rotors  
by WA8UEG on April 11, 2017 Mail this to a friend!
The pot is the same for the CD45, Ham IV & T2X and I get all parts from Hy Gain. I re build a few a year so I buy enough of the common problem parts to do several rotors to save on the shipping.

From their web site:

POT ASSEMBLY, CD45/H4/H5/T2X 39.95
RE: Saving Money On Rotors  
by KC8RPD on April 11, 2017 Mail this to a friend!
I'd use nickel-base antiseize; copper based can cause difficulties...
RE: Saving Money On Rotors  
by K2LGO on April 13, 2017 Mail this to a friend!
AE7IS...Is this the part your looking for...recent google search returned this...@39.95 from C.A.T.S...
[most 8-wire]
Potentiometer Assy., approx. 500 ohm resistance. This is the best and latest version that Hy-Gain has made. Took them 5 tries to get it right ! Prev. Old PN was 5
Saving Money On Rotors  
by KG4SAQ on April 13, 2017 Mail this to a friend!
I've never had a problem with copper-based anti-seize compounds; would be interested to hear what issues others have found with them.
Saving Money On Rotors  
by KD4AVP on April 14, 2017 Mail this to a friend!
Great article. In the process of taking down my 25 plus year old rotor and will do the steps laid forth here. Hopefully the next owner of it will get a long service life from it just as I have. Will replace several key components as recommended by the OP. When you think about it..rotors are really quite amazing pieces of gear. Exposed to the elements 24/7, carrying various size loads...and they give years of service if serviced properly from the beginning. Heard a ham make a comment at a hamfest some many years ago..why should I pay $500 for a rotor? I can find a "cheap" rotor that will do the job for less money. Needless to say..less than 18 months later he was taking it back down to start all over...using a $500 rotor this time.
RE: Saving Money On Rotors  
by WA8UEG on April 14, 2017 Mail this to a friend!
Thanks, they are amazing. I put a used CD45 in service in 1975 and used it until last year. It was still working fine. I cleaned the pot and replaced the bearings and bearing retainers (I replaced just because it was open & on the bench and cheap to do) along with a good cleaning of the gears and it still is going strong. The Ham IV I am using in my tower with the stacked beams (pictured above) now works as good as new and am sure will still be going strong when I'm in the big ham shack in the sky.

As long as you center them perfectly and watch the wind loading they will go decades.

The T2X pictured above was obviously stored for years upside down, it's the worse rotor I had ever seen but looked and worked like new with some careful cleaning, elbow grease, primer & paint and a few new parts.

Saving Money On Rotors  
by ZL1BBW on April 15, 2017 Mail this to a friend!
What grease do most people use in them? temps here min probably 10degress and max mid 30's but quite humid.

Thanks gavin ZL1BBW
RE: Saving Money On Rotors  
by WA8UEG on April 15, 2017 Mail this to a friend!
A very very thin coat of white lithium works fine. About all that is needed for a complete rotor is a about thimbles full or so. A T2X requires a bit more as it has 3 sets of bearings vs the CD45, Ham IV, Ham V which only has 2 sets. Also, the CD45 uses half the bearings of the Ham IV & HAM V so about a thimble will do.
RE: Saving Money On Rotors  
by G3RZP on April 17, 2017 Mail this to a friend!
It's worth cleaning and greasing and re-using the stainless bolts that hold the shells together, because they will be pre-stretched. Grease all the bolt, because stainless in aluminium does get corroded pretty solid. Last maintenance took me 45 minutes just to get those bolts, despite the grease!

If your tower is used as a vertical and the beam is capacity hat - or isn't meant to be but is anyway - put a flexible strap from the tower to stub mast so that RF doesn't flow through rotator. That's how I lost an indicator pot. I've also bypassed the wires to the pot to ground with 0.01 mFd 250 volt caps.

My T2X has been up 31 years and has been serviced at about 10 year intervals. One problem is the need to 'rock' the rotor sometimes to get the wedge out. I've helped that by taking a 115 to 6.3 volt 1 amp filament transformer and putting the 6.3 volt winding (now giving 12 volts) in series with the supply to the brake. A slugged relay connects AC to the primary for about 1 second.

I've also got another slugged relay that delays the brake engagement for about 2 seconds after releasing the drive to the rotor.

A 6.8 ohm wirewound resistor in series with the pilot life increases life - as in 31 years so far!

The non-polarised electrolytic failed after about 18 months, so I took a 100 plus 100 microfarad 350 volt electrolytic from an old radio, wrapped the case in insulating tape and used the two capacitors in series as a non-polarised electrolytic. That's been working for nearly 30 years now.....

One trick for checking the stub mast is centred in the bearing above the rotor is to measure the current drawn as the rotor rotates. This is best done with an analogue meter as it is easier to see a change in current. The current should be substantially constant throughout the whole 360 degrees.

I have had trouble with the bolts holding the rotator down working loose. The best answer is stainless steel tab washers: not having any, I fitted a plate under the holding down bolts so they couldn't work loose. They should be well greased or anti-seized.

When opening up the rotator, doing it in a cardboard box limits the possible loss of filthy greasy balls getting loose. It is probably best not to do this job in the lounge, as it is probably the dirtiest job in ham radio! Washing the motor assembly in WD40 gets a lot of dirt out, as does washing the two housing shells. But make sure that the WD40 has all evaporated before letting either end stop switch open as the spark could ignite any vapour.

I bought the T2X new and it was about $600 equivalent in the UK. So that's about $20 a year. The CD45 on the VHF antenna was obtained NIB with controller by the XYL for the equivalent of $30 when the company she worked for moved to Scotland and the radio club folded before they had chance to put up the beam and rotator!

Even the T2X is a bit small for some of today's beams: I originally had a 205BA for 2 and Cue-Dee 4 element for 15 with 4 elements for 10 interleaved - a Swedish made beam. The 4 element SteppIR is a lot easier on the rotor.

RE: Saving Money On Rotors  
by WA8UEG on April 17, 2017 Mail this to a friend!
The T2X brake sticking problem, end of rotation, etc. is why I always recommend the Ham Supply modification. Handles all the problems at a very fair price, I think the point and shoot without everything else you get is worth it. (I have no connection with them other than I have purchased and installed several)
Saving Money On Rotors  
by N6JSX on April 23, 2017 Mail this to a friend!
When I refurb'ed my CD rotor 25yrs ago (a swap-meet $15 find) the handiest thing was my dual-wheel grinder - I removed one wheel/guard and installed a wire wheel. The wheel was placed to hanging over the edge of my work bench. [lesson learned, get a wheel that has twisted wire brushes - when wires snap off (and they will) they are very less likely to smack you in the face.]

The next item was smaller hand-held drill wire wheels.

Sure can clean up almost anything with a grinder wire-wheel. The hardest part was finding replacement parts for the rotor. This rotor only 6 ball bearings that had slipped out of the retention fingers. I removed the fingers and bought enough bearings to completely surround the circumference. I used a lot of high-temp anti-water-soluble white grease to hold all the balls in place until I trapped them with the upper body of the rotor.

One other thing I did of GREAT help; I found an 8-connection in-line vehicle/trailer WX-resistant type male-female connector. I used crimp ring-lugs (that I soldered) on the wires attached to the rotor and then applied lots of non-conductive grease before closing the rotor connection door. I will NEVER have to wire the rotor in-place and drop those darn small screws or use folk-lugs that wiggle loose. If/when I ever need to remove the rotor I just pop the WX connector and lower to the ground. This one simple connector allowed me to do all the finesseful work ON THE GROUND!

The one big thing over my many years of HAMdom - is the rotor controller phase-shift motor starter capacitor goes bad every few years. Good news it is a simple ground item to fix, bad news is finding them, as the same time replace/convert the controller bulbs with LEDs!

Kuby, N6JSX /8, MS-EET
RE: Saving Money On Rotors  
by K5XOM on April 25, 2017 Mail this to a friend!
I took apart an alliance HD-73. After I reassembled it, I couldn't get it calibrated. I think it must have something to do with where the feedback potentiometer is positioned in it's travel. But since I have never worked on one I am having some difficulty figuring it out.
RE: Saving Money On Rotors  
by WA8UEG on April 25, 2017 Mail this to a friend!
The motor assembly should have an "O" mark on it and the bottom housing should have a small dimple. Make sure those were aligned when assembled then:

Run the unit full counter-clockwise by pressing
left side of control switch. When rotator reaches
stop, release the control switch. Leave main power
switch "on". If meter pointer is not on left-hand
"S" adjust it to read exactly on "S" with a
small screw-driver through the hole beneath the

Now run rotator to clockwise stop by pressing
right side of control switch. Release switch. Using
"Calibrate" knob on panel, adjust meter pointer to
read on right-hand "S". Your HD-73 should now calibrated.
RE: Saving Money On Rotors  
by WA8UEG on April 25, 2017 Mail this to a friend!
I can provide a link to the manual that shows the location of the "O" and dimple if needed.
Looking for old TV Rotator  
by N2LEE on April 26, 2017 Mail this to a friend!
I am looking for an old Alliance U-110 TV rotor if anyone has one in their junk box.
RE: Saving Money On Rotors  
by K5XOM on April 29, 2017 Mail this to a friend!
Yes, please send me the link.
RE: Saving Money On Rotors  
by WA8UEG on April 29, 2017 Mail this to a friend!
Here is the link, the diagram is on the last page.

Hope it helps!
Saving Money On Rotors  
by KG7A on May 3, 2017 Mail this to a friend!
Thanks Steve for all the info on rebuilding rotors. Thanks for all the comments as G3RZP, Peter described with the electronics, and KC8RPD, Richard and KG4SAQ, Bill on the anti-seize comments. Also thanks to AF6AU, Jon for his input. All in all this is a very informative article. Since I have some used rotors, I'd better start opening the hood...

Thanks, Ronny KG7A
RE: Saving Money On Rotors  
by K5XOM on May 5, 2017 Mail this to a friend!
WA8UEG, thank you for the link.
RE: Saving Money On Rotors  
by K1PCG on May 7, 2017 Mail this to a friend!
Thank you for all the good info!
RE: Saving Money On Rotors  
by K1PCG on May 7, 2017 Mail this to a friend!
Thank you for all the good info!
Saving Money On Rotors  
by NA4RA on May 10, 2017 Mail this to a friend!
Excellent Article! Thank you for all the information and your wealth of knowledge! It is much appreciated. 73
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