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Old August 5th 14, 09:48 PM
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Quote:
Originally Posted by Bert[_3_] View Post
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
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?
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Old August 5th 14, 09:56 PM
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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...
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Old August 5th 14, 10:34 PM posted to rec.radio.amateur.antenna
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Default Performance of low-cost rotators in cold?

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
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Old August 6th 14, 05:55 PM posted to rec.radio.amateur.antenna
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Default Performance of low-cost rotators in cold?

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?





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Old August 6th 14, 07:02 PM posted to rec.radio.amateur.antenna
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Default Performance of low-cost rotators in cold?

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



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Old August 6th 14, 09:34 PM posted to rec.radio.amateur.antenna
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Posts: 3
Default Performance of low-cost rotators in cold?

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
* Killfiling google & XXXXbanter.com: jonz.net/ng.htm
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Old August 7th 14, 12:37 AM posted to rec.radio.amateur.antenna
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Default Performance of low-cost rotators in cold?

In t Jonesy W3DHJ
wrote:

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...


My googlegroup filtering is a bit more selective; I only kill "thread
starting" posts from googlegroupers, but allow their followups.

--
Bert Hyman W0RSB St. Paul, MN
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Old August 7th 14, 04:07 AM posted to rec.radio.amateur.antenna
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Default Performance of low-cost rotators in cold?

On Wed, 6 Aug 2014 23:37:53 +0000 (UTC), Bert wrote:
Jonesy W3DHJ wrote:
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...


My googlegroup filtering is a bit more selective; I only kill "thread
starting" posts from googlegroupers, but allow their followups.


As well, I do the same. But to add that much detail to my .sig ain't
worth the complaints I would receive from the usenet police about
a "too long" .sig. :-)

73
Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
* Killfiling google & XXXXbanter.com: jonz.net/ng.htm
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