I'm in the process of finding out whether we can lock into any OTA signals from our homemade rooftop antenna.

A friend gave me an older rotator (brand unknown -- no markings) to help with positioning a homemade CM4221-style antenna.

Thing is there was no controller included with the rotator and have no idea on what the input voltage would be in order to turn this thing. There is a long 3-wire flat cable coming from the unit's inside terminal board.

And after I get it to turn then something will be needed to remotely adjust the position of the mast.

Appreciate any ideas on how to ID the rotator, or at least determine the input voltage to drive it, and how to make up a simple [temp] controller to run it.

I'm doing this to get an idea of just what is available OTA before running out and purchasing all the necessary gear.

Any model numbers or anything on it?

They're typically 18 VDC. So you'd need an 18V transformer (capable of at least 1Amp) and a 68uF capacitor attached across the forward and reverse leads to start the motor.

It might be easier to use to tvfool.com and manually point it...

To help identify this beast, here are some pics of it.

The only numbers that are evident: cast on the turn-stem and another blue-stamped inside the housing :o

They're typically 18 VDC. So you'd need an 18V transformer (capable of at least 1Amp) and a 68uF capacitor attached across the forward and reverse leads to start the motor.

It might be easier to use to tvfool.com and manually point it...



Thanks. AntennaWeb and TVFool.com give me some tantalizing clues as to what to expect here at various locations within Greater Victoria, BC (Canada). So I have an idea of what's available -- I just want to get the antenna as high as is practical then use the rotator to help in positioning it for an even better idea.

So, my next question will be how to locate the forward and reverse terminals -- 1,2, or 3?

Then, what simple components be can be used to slowly adjust one direction or the other?

Jackism,

Personally, if I were thinking about installing this unit "outside"; I would just go ahead and get a whole new rotater system. Once winter hits; if the unit fails; I certainly wouldn't want to have to climb up on the roof.(Ouch!!) That unit looks "at least" 10-15 years old.

A new CM 9521A will set you back around $60.00-$70.00 or so. It's a great unit for light to medium weight systems.

Just a thought.:)

Jackism,

Personally, if I were thinking about installing this unit "outside"; I would just go ahead and get a whole new rotater system. Once winter hits; if the unit fails; I certainly wouldn't want to have to climb up on the roof.(Ouch!!) That unit looks "at least" 10-15 years old.

A new CM 9521A will set you back around $60.00-$70.00 or so. It's a great unit for light to medium weight systems.

Just a thought.:)
I hear ya -- that's my ultimate intention. But first I wanna get more of a handle on whether OTA is going to even work well enough for my location. Now, if I could have found someone locally who would be able to do a reception survey for me, then this exercise might be moot. On the other hand, it's rather interesting learning as I go.

Looks like one of these http://www.summitsource.com/product_info.php?ref=1&products_id=4602
Controller is only 7 dollars less than a whole new unit. http://www.summitsource.com/product_info.php?ref=1&products_id=6104
John

Looks like one of these http://www.summitsource.com/product_info.php?ref=1&products_id=4602
Controller is only 7 dollars less than a whole new unit. http://www.summitsource.com/product_info.php?ref=1&products_id=6104
John


Thanks, John. I'll keep that in mind if I decide to get the full meal deal -- btw, Summit, among others tend to make up low pricing by high shipping costs to outside the US. There are Canadian etailers here that may be more reasonable.

As indicated above, in the meantime I want to try and make this rotator work while conducting my experiment.

I haven't used that one, but most of the older rotators like that used 24-36 VAC with a separate starting winding needing a starting capacitor that was located in the controller. I would think more trouble than its worth.
John

I'd forget about the rotor for now. Do a temporary antenna install for a reception test. Once you know the results, you can decide if a rotor is needed.

I'd forget about the rotor for now. Do a temporary antenna install for a reception test. Once you know the results, you can decide if a rotor is needed.

That's what I'm trying to do: mount the antenna temp on the chimney and slowly rotate it while running through all the channels -- pretty hard to do by oneself don't ya think?

I figured why not get this old rotator to work somehow, even for a temp hookup.

Jack,

Grab a friend and two cell phones. One's precariously perched on the roof, the other is comfortably seated in front of the TV. Start rotating and talking -- problem solved.

Then, buy a new rotator!

meh.. hah :p the point is I wanna fix this thing and move to the next part of the exercise -- isn't that part of what a hobby is about?

Now.. appreciate some constructive advice on how to get this rotator up and running ;)

meh.. hah :p the point is I wanna fix this thing and move to the next part of the exercise -- isn't that part of what a hobby is about?

Now.. appreciate some constructive advice on how to get this rotator up and running ;)

Yeah, but the point is the old unit isn't worth resurrecting, considering the price to do so. Even if you could get it working inexpensively (find an old controller for cheap), a unit of that age could go at any time. Rotors are mechanical devices that have a limited life span, and you have no idea how much use it's already had. Since you've got it down, putting it back up again and expecting it to work for any length of time is a real crap shoot.

Get a friend, do a test, and see if a new rotor is needed.

Here's a thought. Ohm out the connections. Find two terminals that have an ohm or two but not zero ohms. That is probably a motor winding. Hook these up to a car batttery. If it was a DC motor the rotator will turn and you can use it for testing. If not it will pobably burn out. Then you can throw it away with a clear concious.
John

Yeah, but the point is the old unit isn't worth resurrecting, considering the price to do so. Even if you could get it working inexpensively (find an old controller for cheap), a unit of that age could go at any time. Rotors are mechanical devices that have a limited life span, and you have no idea how much use it's already had. Since you've got it down, putting it back up again and expecting it to work for any length of time is a real crap shoot.

Get a friend, do a test, and see if a new rotor is needed.
Jeeze, Ken .. if you lived near by I ask you out for a beer and we could discuss my real reasons why I wanna make this rotator work!

Here's a thought. Ohm out the connections. Find two terminals that have an ohm or two but not zero ohms. That is probably a motor winding. Hook these up to a car batttery. If it was a DC motor the rotator will turn and you can use it for testing. If not it will pobably burn out. Then you can throw it away with a clear concious.
John

Finally, something I can get a good chaw on and perhaps grab a clear conscious if it sucks :rolleyes:

A car battery! Here I was looking around for an 18 volt converter when I can yank spare 12 and 6 volt car batts and try this sucker out on them. I might even have a couple of spare caps beside to bridge the terminals.
Good idea ..why didn't I think of that? -- thanks John.

Jeeze, Ken .. if you lived near by I ask you out for a beer and we could discuss my real reasons why I wanna make this rotator work!

Real reasons be damned!


Look for a cheap rotor controller on eBay, and go for it....

Real reasons be damned!


Look for a cheap rotor controller on eBay, and go for it....

Hah.. ok smarty pants. What controller will I need? 14 vdc? 18vdc ..or vac? load capacity? Lotsa standalone controllers but good for only certain types of rotators. Besides, by the time I get one it will be 2-3 weeks.

I'll see if this one can be made to work b4 going through the hassle and expense of getting a new assembly.

Hah.. ok smarty pants. What controller will I need?Well, that's the question, isn't it?

It doesn't look like the Channel Master I have, and it doesn't look like any of the other half dozen rotor pictures I've seen, so I don't know what to tell you to try.

Let me have some of the experts here take a look, and I'll change the topic title to be more descriptive.

Here's another idea:

http://www.ea4tx.com/products/ars-rotators.htm

Well, that's the question, isn't it?

It doesn't look like the Channel Master I have, and it doesn't look like any of the other half dozen rotor pictures I've seen, so I don't know what to tell you to try.

Let me have some of the experts here take a look, and I'll change the topic title to be more descriptive.

If I open it completely up and take a pic of the guts ..including the windings and gears.. will that assist in helping with the id?

If I open it completely up and take a pic of the guts ..including the windings and gears.. will that assist in helping with the id?

Wait & see for a few days.

I have to agree that this project isn't worth pursuing. The last time I went out to replace a rotor controller, I found that early Winegard rotors had a different number of pulses per degree of turn than the currentmodel did, so while it turned, the amount of rotation of the antenna did not match the amount of rotation of the knob.

I wouldn't buy a used rotor without a controller in a flea market for a dollar. As noted above, the difference in price between buying a controller alone or a controller with a new matching, warranteed rotor is small. When I compared the two prices at my Channel Master dealer several years ago, I thing the difference was less than $15.

If I open it completely up and take a pic of the guts ..including the windings and gears.. will that assist in helping with the id?

This old 9512C on ebay will turn it,if it's any good.It's an antique CM rotor.I'd take it apart and lube it up good.It may work.

http://cgi.ebay.com/Channel-Master-9512C-Antenna-Rotator-Remote-TESTED_W0QQitemZ190218981646QQcmdZViewItem?_trksid=p3286.m20 .l1116

There's a difference between frugal and cheap. Jacksim, you're not being frugal. Buy a new rotor and be done.

Ok, guys. I stumbled upon a near match to my rotator today. It even came with a semi-functioning controller.
(sans dial cover and internal clock mechanism). The old rusty rotator is identical to mine!

I powered up the antiques and they do work together for a rotation ..and they do need each other to work.

The label on the controller says manufactured by Crown Mfg. The model number is RC-18.

As with our '55 Chev p/up and various vintage Catalin radios, this too has got me intrigued.

Anyone familiar with these old models? Anywhere I can see a parts list/schematic and perhaps a user manual?

See
http://www.digitalhome.ca/forum/showthread.php?p=782800
http://support.radioshack.com/support_video/doc44/44901.htm

See
http://www.digitalhome.ca/forum/showthread.php?p=782800
See? Not necessary. It's the same person asking the same question.

See

http://support.radioshack.com/support_video/doc44/44901.htm

Great! Kinda thought there should be a 3rd party application for this unit, and so thanks for directing me to the RS part. I should now be able to at least remotely turn the antenna to test my reception perhaps by using a stopwatch to 'time' the position and thus avoiding coax wrap-up around the shaft.

Again, if it proves successful, I may purchase all the state-of-art parts needed for OTA.

See? Not necessary. It's the same person asking the same question.

Sheesh.. hope this wasn't taken as an insult to this thread and site. I wanted to gather as much info on this unit asap. DHC also has a very good OTA approach -- thanks for pointing that out :o ..and thanks guys for your thoughtful assistance :D

..now to see what programming this whole contraption can round up.

Great! Kinda thought there should be a 3rd party application for this unit, and so thanks for directing me to the RS part.

Odds are good the rotor control will not be cheap. Let us know.

Great! Kinda thought there should be a 3rd party application for this unit, and so thanks for directing me to the RS part. I should now be able to at least remotely turn the antenna to test my reception perhaps by using a stopwatch to 'time' the position and thus avoiding coax wrap-up around the shaft.

Again, if it proves successful, I may purchase all the state-of-art parts needed for OTA.

There's a metal stopper in the drive unit which will prevent it from turning beyond 360��°, so coax wrapping around mast shouldn't be a problem.

I found that there was indeed a stopper on the rotator, which helped in keeping the coax in check.

The homemade antenna is mounted on a makeshift pole and at about 10' above the roofline of our rancher. Inside there is the crippled coverless controller that provides no info on direction hense the constant need to go outside to check on the antenna's position. I spent a lot of time running through every channel the tv produced ..with each revolution of the antenna.

Even after polling the results of TVFool's search for my area, the very few channels pulled in were no improvement over what could be had from a set of wabbit ears next to the tv: lotsa noise in the picture.

But there were lots of tantalizing moments when the static was popping in and out and some channels had sound but no pics ..'straining but no dump' as they say.

This was a good fun exercise and methinks if we wanted to carry forward with OTA then an investment in having the signals instrument-tested may be prudent. The trick is to find someone locally that's still into this stuff.

Another problem is that our neighbourhood is well-established with many tall evergreens so exploring OTA may be moot in the end anyway.

As for keeping this rotator, I probably won't if we decide to carry on with OTA. We'll just purchase everything we need new from scratch -- state of the art.

Our original approach to OTA was as augmentation to either commercial or FTA satellite. This would perhaps free us from our local catv co.

Thanks everyone for your suggestions. Great forum!

I'm not sure if anyone actually answered the question here...

This is a low quality rotor I believe made by a company named Crown and sold under dozens of other brands. It uses a synchronous AC motor that runs off of 24v ac. It has a common terminal and 2 field coil terminals, one which you apply 24vac directly to and the other you apply 90 degree phase shifted 24vac to by connecting a capacitor in series with it and the transformer output connected to the first field terminal. You reverse direction by reversing which field terminal has the capacitor connected to it. You should be able to determine which terminal is common with an ohm meter, common to both field terminals should be about equal resistance, between the 2 field terminals should be about twice the resistance of any other pairing. Nearly all rotors run the motor this way, they just have different positioning sensing systems and that is what the 4th or 4th and 5th wire are for on other designs. Since this rotator is a synchronous motor, it turns at a more or less constant rate(one RPM at the output shaft for the antenna I believe). The control box tracks its position by timing how long the motor has run. In most of the control boxes, there is simply a second synchronous motor connected in parallel to the rotor that moves the pointer on the control box. Some computer controlled control boxes time the position electronically.

If you do buy another rotor, I would suggest you buy a Cornell Dubilier/CDE/CD or Alliance wither new, NOS, or rebuilt from Norm's Rotor Service, it will be much higher quality and similar price than the new Crown type rotors.