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Author Topic: Cheap rotator or DIY?  (Read 9880 times)
CHRISDX
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Posts: 244




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« on: February 14, 2013, 07:55:12 AM »

hi all, I need to rotate my OTA TV antenna and FM broadcast, and might wish to add 2m beam as well. Small array. I was thinking about a standard TV rotator but un like the old ones from Tenna Rotor etc which were old school reliable, this new stuff is hit-or-miss toy-grade crap from China. Sad but true - have researched all the reviews and no other conclusion can be reached. I dont totally trust an old rotator from ebay or whatever, so then I realized these are not rocket science! I could make a waterproof housing with bearings and some kind of DC motor, but would have to work out a reliable positioning mechanism.

Anyone done this for a project?
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WB6BYU
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Posts: 13149




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« Reply #1 on: February 14, 2013, 11:51:31 AM »

I rotated a push-up mast by attaching a handle to it with a U-bolt and
turning it by hand.

I've seen hydraulic and pneumatic systems.

Probably the simplest was a cable wrapped around the mast that ran
over pulleys to a crank handle on the wall of the shack.  He said he
worked several rare DX stations because he could crank the beam
around faster than those using electric rotators.  The cables ran
through the ceiling and down the wall to the crank, so he just put a
flag on the cable and marked the corresponding antenna direction on
the wall as it moved up and down.

However, there are a number of older Hy-Gain rotators available on the
used market at Hamfests, etc., and they can be rebuilt by places such
as Norm's Rotor Service (or by many hams) to give long service.
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CHRISDX
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Posts: 244




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« Reply #2 on: February 14, 2013, 12:02:58 PM »

You know, I had similar ideas. I have two choices, a mast on the house, or a standoff mast on one of my 2 70' Oaks behind the house where I could get much higher without a mast or tower (which I have to be careful, a mast ok a tower I think needs permitting, technically) A tree doesnt, and its already there!  But the rotor would then need to be electric. Also, I would either have to have long standoffs bolted to the trunk with SS lags, or sacrifice some of the swing (and make some kind of stops). A mast on the house could be 360 degrees. How tall could a unsupported mast be anyway? The Roof edge is about 8' up where it could be bolted. My G5RV needs just over 30' in the center I wonder is a small top-mast could support that with some kind of swivel above? And then would the G5RV wires interfere? Or I could use a lighter mast there on the southeast corner just for G5RV support, and the rear peak, about 15' up could support a mast for the TV and small beams etc, with a mechanical/manual rotator? Would that be a mast within the main support mast? bearings?
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N5VTU
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Posts: 361




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« Reply #3 on: February 14, 2013, 12:28:56 PM »

I was in Lowe's about a week ago and noticed this on the electrical aisle.


http://www.rcaaudiovideo.com/search/?ks=vh126

It's light duty and probably made in China, but for $69 and a one year guarantee, it might be worth the gamble.  It includes the rotator, digital controller with memories, and even an infrared remote control.

Stephen
N5VTU
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CHRISDX
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Posts: 244




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« Reply #4 on: February 14, 2013, 02:29:10 PM »

Thanks but these Chinese junkers have a bad rep. Frozen / broken gears, water ingress, and they get out of alignment almost immediately. No thanks. I'd rather go manual, or build something, or *maybe* buy a good used rotor.
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N5VTU
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« Reply #5 on: February 14, 2013, 02:58:48 PM »

Thanks but these Chinese junkers have a bad rep. Frozen / broken gears, water ingress, and they get out of alignment almost immediately. No thanks. I'd rather go manual, or build something, or *maybe* buy a good used rotor.

Then I think a used, but rebuilt American unit from Norm is your next best option unless you go DIY.  $149 for this little gem.

http://www.rotorservice.com/images/U110RC%20Nw.jpg 

Stephen
N5VTU
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KB9JXZ
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Posts: 36




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« Reply #6 on: February 14, 2013, 03:41:41 PM »

 I purchased a RCA VH126 rotor from my local big box lumber yard two years ago and it has worked great. Bought a second one just a month ago. Really like the whole 12 memory remote also. I always replace the zinc hardware with stainless and use no-ox or whatever you want to call it.
 I can't help but wonder if the hams who complain about the cheap China junk have too large of an antenna on it and also overload their tower with antennas to a scary level. Maybe I just got lucky. My two cents.
 73
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CHRISDX
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Posts: 244




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« Reply #7 on: February 14, 2013, 03:48:08 PM »

Yeah I WISH this wasnt the case but...  the reviews I saw were on Amazon and other non-Ham places, unfortunately. Here are some excerpts:

http://www.amazon.com/RCA-VH126N-Antenna-Rotator-Remote/product-reviews/B002GSG0CG/ref=cm_cr_pr_btm_link_next_2?ie=UTF8&pageNumber=2&showViewpoints=0


After the installation, I plugged it in and fliped the power switch and nothing happened. After confirming I had power to my receptical, I took the cover off the control box. One wire was not soldered to the power switch, so I got out my soldering iron and made the connection. The control box works fine now, but the remote control doesn't work.

Seen the reviews were not to bad so i bought it. If you notice the Phillips brand recieved very bad reviews but the item looks exactly the same. Both are made in China. I ordered the first one (RCA)and it came quickly, and set up easily. You will be told to do a 360 degree test before installing antenna to make sure it goes around.. This should have been my clue about reliability. I did the test and it worked. Put it up on the mast, installed the antenna and then took it to 360 degrees again. Thats where it stayed. The motor would not bring the rotator back. I took it off the roof and tested it without an antenna. Still stuck, no sound, nothing. I ended up having to send it back (KEEP THE BOX).. The good news is that amazon returns had me another one within one day and they were awesome do deal with. I asked for a replacement.
When I got the new one and opened the box, i ended up opening the trap door where the wiring connects to the rotator. The first thing i noticed is one of the wires broke off that comes from the motor. It needed to be resoldered on. What kind of quality is that. I did the 360 degree test and made sure it went around once. Thats where dejavu came in. It locked in place and wouldnt go the other way. I could hear the motor humming but it would not move. I had to look up online the RCA customer service (which is audiovox in NY). The representitive actually asked me how I knew it wasnt turning. After i explained to him it doesnt go the other way and is stuck, i was told that it doesnt sound like that is supposed to happen. Basically they were useless. I ended up taking the motor out and pulling everything apart. It appears the motor is mounted a little off so the gears are not matching correctly. I ended up drilling out the motor mounting holes a little bigger so i could manually move the motor around as i tightened the screws and got the motor gear to match better. So far it goes back and forth now without issue, but if i had a choice to do it all over, DONT BUY THIS BRAND OR ANYTHING THAT LOOKS LIKE IT THAT SAYS MADE IN CHINA IN FINE PRINT.


I have bought two of these units in the past 14 months. The first unit worked fine for just at 13 months, then locked up. The rotator unit went to 00 after I hit the "INIT" button - and never moved again. Just outside the warranty - naturally.

I only used the device during the first few weeks to set the best signal strength, after that - I did not touch it again for many months. The only reason I used the rotator again after about 6 months was to adjust it after I had replaced the coax lead in wires. I got the unit set up - great signals etc. When I went to store the new setting - I hit "INIT" instead of "MEMORY". This is THE largest failure - poorest design with the unit. The INIT causes the antenna to go to 00 - while the base goes to 36 and count down - trying to send the rotor to 00 the whole time. If the INIT button is allowed to be used - why does it lock the unit at 00 never to move again? The rotator now just hums when you send it signals. That button ought to have a lock on it so as to confirm you really want to "INIT".

I bought the second unit once the first unit locked up, I installed it yesterday - was tuning it this afternoon - and again - hit the #^$*#@ "INIT" button by accident - and now this NEW unit is locked up. It lasted all of ONE day.

Made in china - what quality.... Do NOT buy this unit unless you need a new paper weight. RCA is not what it used to be and there are no Made in America products to do this anymore.

Now I get to mess with "Audiovox" to go through all the expense of sending dead weight in for warranty on another piece of junk. Thank goodness for USPS if it fits it ships....

Nothing wrong with Amazon nor the company that shipped it - the unit is just junk.


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KB9JXZ
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Posts: 36




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« Reply #8 on: February 14, 2013, 03:50:28 PM »

Guess I'm just lucky
73
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CHRISDX
Member

Posts: 244




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« Reply #9 on: February 14, 2013, 06:51:24 PM »

So, back on track, while we wait for a DIY person top throw in here, whats are some good ham rotors that are accurate and reliable to look for used perhaps?  Maybe thats the way to go... I just need some models that have good track records...
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W1JKA
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Posts: 1622




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« Reply #10 on: February 15, 2013, 07:40:42 AM »

   Depending on antenna mast location in relation to your house I can offer one prooven solution.Back in the day (1950s) our free turning 30 ft. tv mast pipe was locacated just outside the tv room window,it stood off the side of house by about 14 in. due to eave overhang.Dad took an old solid rubber tire 12 in. trycycle wheel slid it over the mast and made it fast at window level.It was my job to open window grab the wheel and rotate per dad's instruction.Directional indicator was strictly visual by day and illuminated by flashlight at night.Never had a failure,just cold hands in the winter.
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K4RVN
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« Reply #11 on: February 15, 2013, 07:05:16 PM »

Walmart sells it so try it and take it back if it fails during the warranty of one year if you are inclined. It may be under another brand, but looks the same.
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W4HIJ
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Posts: 367




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« Reply #12 on: February 15, 2013, 07:18:39 PM »

They don't make stuff like they used to. I've got two Gemini Orion OR-360 rotators that used to be widely sold for TV antennas. I got the tip to buy them and where to buy them when I was putting together  my satellite station. Lot's of gearing driven by a tiny little DC motor but they work reliably and have position pots to indicate direction. I controlled them with this..... https://sites.google.com/site/marklhammond/saebrtrack Probably too much for what you want to do and i no longer know where the surplus OR-360's are available these days.
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KM3F
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Posts: 501




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« Reply #13 on: February 16, 2013, 06:01:41 PM »

From experience, there is a quality difference between the Phillips rotor and a Channel master.
While they look very much alike the CM rotor uses a steel gear train.
Both are 26 volt AC powered and actually can use the same controller interchangeably.
The internal motor is the same one in each.
You would be ok using CM rotor with TV, 2 Meter, 440 beams as long as the rotating inertia, wind load etc are not to high and it's not used high on a tower that cannot be easily pulled down for any issues with it.
These have no brake of any sort but rely on the gear reduction ratio to keep them in place.
The direction indicators each uses is based on time of rotation that is reset when you would do the calibration.
The calibration runs the rotor to end of rotation as the means to a reference, then times it from that point on.
This is the only way it can be done using only a 3 wire power feed.
The rate of rotation is good enough for general use using beams that do not have very narrow beam width patterns up to about 8 elements or so.
Some other consideration are the number of coax cables a the rotation point, keeping them from snagging in hot weather etc.
I use home made eye loops about 12" out from the mast and another out from the tower or mast pipe to keep the coaxes out away and have no chance of hangups.
Do watch trying to turn the rotor in freezing ice conditions as a freeze fast could do damage.
I use the CM rotor on 10 foot of tower with 18 feet of alum pipe up top and a 2m and 440 beams just to play with and easy to take down and work on or take the whole assembly to a mountain top to play out of mobile as the base mount is made to run on with a vehicle wheel and stand up without guy ropes.
The rotor is powered by a 12dc to 120 volt ac inverter as the rotor does not take much power.
Good luck..
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CHRISDX
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Posts: 244




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« Reply #14 on: February 16, 2013, 07:10:38 PM »

What I would like most is a rotor that tells me where it is at all times, not guess. Which small ham rotors should I look for buying used? Something reliable but not a budget breaker.
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