: Rotors for OTA: Channel Master, Nexxtech/Archer, Yaesu, Hy-Gain, Others
2010-12-16, 10:29 PM
What about replacing the controller with one that has a bit higher output?The controller is really just a timer, as other members were recently discussing, and a rotor is unlike an electrical motor that has windings, a yoke, and an armature. A rotor works due to the electromagnetic attraction of one applied voltage in one direction from the current position, and setting the controller in the other direction applies a voltage in that other direction, causing the rotor to reverse itself.
So, increasing the power may not do what you expect because all of the applied voltages would be raised equally. Does that translate into higher torque that could blast past ice jams? I've honestly never tried it, but my understanding of electrical theory says the rotor will burn out before it achieves much more torque. Again, I've never tried it. ;) Anyone?
As for greater turning power, that's when you're talking about Hy-Gains and Yaesus. :)Install instructions did not call for thrust bearing. It probably would add drag. Thrust bearings are made of a low-friction rubber-like material or soft metal, so they do not tend to affect the turning power of a rotor. Their purpose is to add rigidity in the vertical plane to the pole above the rotor, with the payoff being that the rotor only has to deal with turning motion as opposed to vibrations above it that wear it down. A rotor with a thrust bearing at least 2 feet above it will last years longer than a rotor without.
2010-12-17, 12:39 PM
Thrust bearings are made of a low-friction rubber-like material or soft metal, so they do not tend to affect the turning power of a rotor. Their purpose is to add rigidity in the vertical plane to the pole above the rotor, with the payoff being that the rotor only has to deal with turning motion as opposed to vibrations above it that wear it down. A rotor with a thrust bearing at least 2 feet above it will last years longer than a rotor without.
True. A thrust bearing may actually decrease the drag due to the decreased lateral forces on the internal bearings (Physics explains that the lateral force on the thrust bearing will be lower than what was on the rotor, due to decreased leverage).
2010-12-17, 01:44 PM
Install instructions did not call for thrust bearing. It probably would add drag. I suspect the issue it thickening lube.
Thanks. I was just trying to gain some context with the issue.
I can't say whether a thrust bearing installation will help the issue with the CM rotor. If you suspect the lube is the failure, I would disassemble, degrease what's in there, and apply a low-temperature grease. Of course this would likely void any warranty; only attempt this if you're technically inclined and willing to risk the warranty.
The DMX Thrust Bearing, which I use, glides perfectly. Though I have seen older ones which are pretty much seized up. If anyone is experiencing freezing up, and has an older thrust bearing, I would certainly check this first.
2010-12-17, 02:15 PM
I gather the new CM rotors are made in China. From my own personal experience dealing with Chinese contract manufacturers, you need to be very thorough with your specifications as if there is any place you let them make a choice, they will go with the cheapest alternative and likely will not tell you that they did so (I am sure the reason why a bunch children's toys had lead based paints is they were only told what colour to paint it and let them choose an appropriate paint). For the rotor the problem could be as simple as them using a different brand of grease.
Even when you are specific, I have seen it where they "upgrade" to a seemingly better option (without telling you) if they can't get what you specified. This "better" option may end up causing other problems that seem unrelated to part they upgraded.
2010-12-17, 09:25 PM
What about replacing the controller with one that has a bit higher output? Has anyone done this and cured the problem?
I don't recommend this. You will likely fry the rotor, and end up doing a risky winter replacement...
(I hate climbing towers/roofs in the winter..:) )
2010-12-18, 07:55 PM
Maybe there too much lead in it.;)
2010-12-22, 11:41 AM
I too have telephoned CM support twice now, with no call back. :(
I may just toss the thing in the garbage, and bit the bullet for a more expensive one that will function as advertised.
2011-01-03, 01:26 PM
I've purchased a new CM 9521a knockoff, Antennacraft TDP-2 and a NTE U-106 (new digital model) within the last six months and in every case, each one of these has bit the dust almost immediately after the first use. Each rotor has suddenly stopped working and no longer functions. Only my six year old NTE U-105 still works.
I need a new rotor and one that is going to not only work but last more than a week or two. I plan to mount a Winegard HD7084p or 7698p on it. I only used small antennas on the models mentioned and despite this, they all bit the dust.
Can someone recommend something that will work?
2011-01-03, 02:34 PM
How much are you willing to spend, Billiam?
2011-01-03, 02:50 PM
Perhaps up to $300 just as long the unit is reliable.
Someone recommended a U-100 from Norm's but I'd first like to find out if there are others out there that might be comparable to this unit and not cost a great deal more. I know the AR40 has a good reputation but it looks like it might cost more than I'd like to spend.
2011-01-03, 03:04 PM
I can't remember if you're in upstate NY or Maine, but is there a local ham radio club or organization? They have great swap meets at which you could probably get a Yaesu or Hy-Gain for a good price so that you can say goodbye to your back luck with weak TV rotors once and for all! :) Here in the Province of British Columbia a ham radio operator can get license plates for his vehicle that use his call sign, so maybe that's true where you are. I've had some really good conversations with hams when spotting them in shopping center parking lots. It amazes me how those nice guys can talk for hours and hours on the air and then talk your ear off for an hour in front of a grocery store! LOL :D
2011-01-03, 10:49 PM
The cold weather is back and so is the stuck rotator from CM I pointed at CBC TO for Wall E last night! It was good in the warmer rainy days. I found a way to free it up by reversing multiple times it then syncing it. Goes real slow at first then speeds up to normal. Still no reply from vendor support!
2011-01-04, 10:40 AM
Thanks Stampeder. I wish I did live in either NY or Maine. The economy has me stuck near Kansas City which to be blunt, is not my kind of place.
I have a couple of friends that are Hams (not the meat or comedians mind you) and I may talk to them about it.
I want to find out more about the new Eagle Aspen ROTR100 before I decide to spend some bucks on a more expensive unit like a Yaesu. Hy Gain or the Alliance
2011-01-06, 08:50 PM
I am starting to think multiple stationary antennas may be more cost effective than rotators especially with multiple TVs. I have set up a second test tenna. The only downside so far is switching antenna inputs, all manual so far. My old zenith TV had a coax remote option as an add-on and I still have it around somewhere but it is proprietary to the TV it was made for. Is there anything else out there so I can stay on the couch and switch antennas?
2011-01-06, 09:12 PM
wilspin: There are wireless A/B switches available.
Or you could look into an MATV system that allows you to inject channels into a common feed from dedicated antennae. Though the cost is considerably more than most will pay...
2011-01-06, 09:18 PM
i've been googling it Jase, no luck so far
2011-01-06, 09:28 PM
Which? The wireless a/b switch? Save & Replay (Mississauga) sells them.
2011-01-07, 03:23 PM
Today, I decided to plug in the NTE U-106 just on a whim to see if it would work. I got to thinking that perhaps the control box simply froze up and by unplugging the unit and then leaving it without juice for a while would reset the unit. Well, I lucked out and it worked. Apparently it froze up for some reason not unlike some of my stereo electronics have in the past. Now I have a good rotor that actually works. The U-106 has steel gears that can handle the load of the antenna that I plan to mount. But the Antennacraft unit is still dead and the Centronix CM clone I sent back because neither of those units would start up after leaving the units unplugged for a while and then plugging them back in.
Anyone looking for a quality rotor should consider the NTE U-105 or U-106. They are the only two that I have used that seem to work. Can't comment on the Eagle Aspen ROTR100 though since I have not used it.
2011-01-09, 09:15 AM
I'll throw in some input on the Eagle Aspen ROTR-100. I installed it last summer, and have had a chance to use it for about 6 months now. It replaced an old CM that would lock up in the winter time.
To reduce wind load, I removed an old VHF head that was on the tower, leaving it with a pair of stacked Televes Dat-75 uhf heads.
In a nutshell, it works flawlessly. No uncommanded movement during high wind events, works on the coldest days that we've had, which so far this winter has only been around -15 or so. I've got zero complaints about it.
To install it, I used a separate coax for it, as I didn't want the power going through my feed cable since I'm in a weak signal area with enough challenges as it is. May have worked fine, but I had the other cable up there anyways.
2011-01-09, 09:59 PM
DC power won't degrade signal quality. There may be slight insertion loss--but this would be overcome by preamplifcation (if the rotor is after the preamp).
My concern is using a coax-powered preamp. If the pre-amps voltage requirements aren't identical to the rotor, you could have problems. Likely this rotor won't pass DC anyways (assuming it's set up with an in and out spigot). Thus the separate coax solution is likely the best.