Considering a roof-mounted 3-el 6 meter beam and don't want to have to
spend more than the cost of the antenna just to turn it.

I see a number of apparently mechanically identical rotators intended for
turning TV antennas, ranging in price from about $50 to $120, which look
like they'd work under normal conditions.

We don't have much trouble with ice here, but long stretches of near-
zero or below-zero F temperatures are common, with occasional dips to -20F
or so.

Would these rotators work in those temperatures? Would they continue to
work for more than one winter?

--
Bert Hyman W0RSB St. Paul, MN

In article ,
Bert wrote:

We don't have much trouble with ice here, but long stretches of near-
zero or below-zero F temperatures are common, with occasional dips to -20F
or so.

Would these rotators work in those temperatures? Would they continue to
work for more than one winter?

Some of the ham rotators have their bearing races packed with
low-temperature grease, designed to withstand these sorts of
temperatures without turning into cement.

And, you can open up these rotators and remove the bearings from the
race, clean 'em out thoroughly, and then re-grease them with a grease
of this sort. Reportedly, you should *not* use wheel-bearing grease
or an "extreme pressure" grease loaded up with moly or a similar
fiberous material, as the additive will build up on the bearings and
races... Norm's Rotor Service recommends using either white lithium,
or emerald grease.

The little light-weight TV rotators can also be re-greased. One
review of the Radio Shack rotator suggested that it may not have had
adequate lubrication from the factory (shaft rusted stuck), and that
opening it and cleaning it out and re-greasing it took only a couple
of hours.

Some of the small rotators are said to have plastic gears - these
might not hold up against the torque stress of a medium-sized amateur
beam. Others seem to have metal gears, perhaps tougher.

You might want to install a rain-shedding rubber "boot" above the
rotator... and make certain that the condensation-drain hole faces
downwards, and is not plugged or obstructed!

You might want to see if you can locate a used ham-grade rotor at a
hamfest / flea market, or from a ham who is decommissioning his/her
tower ("silent key" sales, "we're selling the house and moving, come
take it down and take it away" situations, etc.).

I picked up an Alliance HD-73 rotator and a (slightly broken) control
box for a song at a ham flea market a few years ago. 2-3 hours of
work were enough to disassemble it, scrub out what little remained of
the original grease (now about the consistency of grout), clean the
ball bearings, thoroughly re-grease, and reassemble. It's not a
difficult job... but *always* disassemble a rotor while holding it
in a large cardboard box with a sealed bottom. Otherwise you *will*
end up chasing loose ball bearings across the floor, and you'll never
find them all (a cautionary warning I'm glad I read before starting
work!)

(David Platt) wrote in news:quo7bb-
:

And, you can open up these rotators and remove the bearings from the
race, clean 'em out thoroughly, and then re-grease them with a grease
of this sort. Reportedly, you should *not* use wheel-bearing grease
or an "extreme pressure" grease loaded up with moly or a similar
fiberous material, as the additive will build up on the bearings and
races... Norm's Rotor Service recommends using either white lithium,
or emerald grease.


I don't if those are perfluoro polyether greases, but anyway, that's what I
suggest. I've not had the same need, but given that these greases are used in
car parts, and have helped me retore LONG working life to mechanisms that
other greases have failed in, I think PFPE is the way to go. One that I dn
know by name is Krytox, found easily in public domain because it's sold for
scuba breathign gear.

One thing: Use generously, don't scrimp on it because it tends to part
between two moving surfaces rather than gloop between them, so you don't waht
cracks opening up to let dust in to form a grinding paste. Use enough of the
stuff, and it keeps everything out short of direct physical force.

One more thing (no-one expects the Spanish Inquisition) : I do not know what
its UV resistance is....

I can't speak for all rotors, but all of the rotors that i have seen over the past 30 years, cannot be taken apart, the parts are not service removable - for a regular television rotor - Channel Master, Radio Shack, RCA etc..

The closest I have come to repairing them was to take a can of PB Blaster and spray the bearing until it freed up and then turn it back and forth until I got as much of the rust out of the rotor bearing as I could.

Most rotor shafts are permanently welded to the armature plate inside of the rotor, but like I said before, if it doesn't have a brake and if it doesn't have a reluctor to tell you where it is pointed - it is a crap shoot every time you use it.

I have a old Channel Master TV Antenna rotor on my one tower that has a Solorcon A99 on the top, a 6 element - Two Meter beam below that and a Six meter dipole below that. But the rotor is nested 10' below the antenna's and the thrust bearing takes all the abuse when the wind blows.
That rotor has to be 40 years old, and it has been on 4 different houses before it ended up on my tower.

You won't find a new rotor with bearing and gears like what is in this rotor anymore. Even when the bearing rusted and froze, all I had to do was spray it with PB Blaster and replace the rubber gasket and it would work as good as new again. The bearing is sealed, I don't know how you could put grease in it. You could put grease around the bearing, but that would only create more problems, not solve them.

There is usually a weep hole in the inspection plate that has to be kept clean so the moisture that accumulates inside of the rotor housing can drain when there is a temperature change.

Lets break your question down into smaller, more digestible parts.
A 3 element - SIX METERS beam has a wind loading of X.
Six Meters - Lets see - the FCC took 6 meters off the television broadcasters and gave it to the amateurs.. 6 meters is just below the frequency for channel 2. How many elements does a good UHF / VHF antenna have?
My answer is many, the Winegard 8200U I had up probably had 8 to each side. Then again, my rotors broke until I discovered how to build them so they wouldn't break.

The rotor in question was a RCA sold in Lowes with a rotor control - VH126N

The problem was three fold.
1. - there was three 1/4-20 bolts inside that were not Loctited and were not torqued.
2. - I did not use an antenna thrust bearing.
3. I did not use guy wires.

So how did I solve the problem?
I threw away the carbon steel components and replaced all of them with stainless steel. I used Green Loctite on all the threads, I put three guy wires directly to the rotor.

Only the very old rotors with bad gaskets has a problem with corrosion or water getting into the bearings. If you buy a new rotor, rob the gasket from the new rotor, take it back to Lowes, tell them there was something wrong with the rotor, get another rotor, then you will have two rotors in working condition.

The thrust bearing isn't expensive - under $100.00 and the rotor is only $80.00
The manufacturer tells us not to place any antenna more then 3 feet above the rotor. So all we have to do is make a plate, attach the plate to the tower, attach the rotor to the plate, center the rotor in the tower, put a thrust bearing near the top of the tower, put the antenna above the tower and we are golden.

If we are worried about corrosion - water getting into the rotor, we can cut a two liter bottle, slide it down the mast and put a hose clamp around the threaded portion of the bottle.

3 conductor - communications grade wire - 24 gauge will work for length up to 100'. No reason to spend $28.00 on Radio Shack rotor wire.
I think the last time I bought 3 conductor it was $.12 cents a foot.

The problem with using a television rotor for ham radio is that it was never designed to be started and stopped and there is no brake inside of the rotor and the rotor will turn in the wind and then you will have to re index it from time to time and eventually the parts inside of it will fail and then you will have to buy another rotor.

A CD 45 rotor can usually be had at a hamfest for about $150 in working condition and even less if someone is just giving it away. Not many of the parts goes wrong, and the parts that does go wrong can still be bought - for a price. Most times with the CDE product the capacitor goes bad.
Same is true with the old Tenna rotors probably laying around in most peoples basements and garages.

The CD 45 has a brake and a reluctor that tells you where the antenna is pointed. Why not use a CD 45?

As far as using a tri pod mount on the top of the roof - Forget it.
If you have high winds - like the high winds I have, you will find your antenna laying on the roof if you are lucky and laying on the ground if you are not.

The commercial antenna mounts are not robust enough to just stick a mast on the side of the house. At the minimum, I would want 1 1/4 semi rigid conduit for a mast and 3 mounts on the side of the house and a ground stake driven into the soil right next to the mast and a stainless steel ground clamp attached to the galvanized pipe.

If you place a copper wire directly to the galvanized pipe, it will cause galvanic corrosion - make the pipe rust!
I would also put a PolyPhaser on the ground stake before I bought the coax into the house.

Mo money, mo money, mo money!

Good coax will also pay huge dividends when working 6 meters.
Belden 9913 or LMR 400 should be on your shopping list...

You should try to get the antenna 10' higher then everything in the neighborhood, or at least 30' - 50' off the ground.

A 70' tower is optimal for working DX...

Channel Jumper wrote:

'Bert[_3_ Wrote:
;823186']Considering a roof-mounted 3-el 6 meter beam and don't want to
have to
spend more than the cost of the antenna just to turn it.

I see a number of apparently mechanically identical rotators intended
for
turning TV antennas, ranging in price from about $50 to $120, which look

like they'd work under normal conditions.

We don't have much trouble with ice here, but long stretches of near-
zero or below-zero F temperatures are common, with occasional dips to
-20F
or so.

Would these rotators work in those temperatures? Would they continue to

work for more than one winter?

--
Bert Hyman W0RSB St. Paul, MN


snip

Six Meters - Lets see - the FCC took 6 meters off the television
broadcasters and gave it to the amateurs..

US amateurs were allocated 56 to 64 MHz in 1924.

In 1949 the band was moved to 50 to 54 MHz to make way for TV channel 2
and it has been that way ever since.


--
Jim Pennino

Only the very old rotors with bad gaskets has a problem with corrosion
or water getting into the bearings. If you buy a new rotor, rob the
gasket from the new rotor, take it back to Lowes, tell them there was
something wrong with the rotor, get another rotor, then you will have
two rotors in working condition.

Oh, what a wonderful suggestion. Steal a gasket, and stick Lowes and
the rotor manufacturer with the cost of refurbishing the one you
plundered. Their shipping cost and personnel time will probably more
than wipe out any profit they made on the rotor you bought. They may
just junk the "bad" rotor rather than go to the considerable
expense of "fixing" it.

This is different than shoplifting, just how?

In (David
Platt) wrote:

This is different than shoplifting, just how?

I filter out all posts with Message-IDs ending in "

--
Bert Hyman W0RSB St. Paul, MN

On Wed, 6 Aug 2014 18:02:48 +0000 (UTC), Bert wrote:
David Platt wrote:

This is different than shoplifting, just how?

I filter out all posts with Message-IDs ending in "

+1 See below...

--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
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