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Bushing for antenna mast extension idea?

rons

Diamond
Joined
Mar 5, 2009
Location
California, USA
Extending a 7 foot pole (1.140 I.D. left side) with a 3 foot pole (1.0 O.D.). The 3 foot pole will have a antenna mounted to it.

The length and material for the bushing would be Al. round or a S.S.304 tube. How long? And I was thinking of using the Al. clamp that
is 1.150 I.D. The clamp will be half over the 1" side with a split ring. The clamp is not wide enough? The weight of the antenna is 1/2 pound.
The 3 foot pole might be replaced with a 5-6 foot length if the signal strength is better. The length of the bushing and what stuff to use?
Or should I use some HDPE? I thought about software that can tell me the right length so that the upper section isn't too stiff, flexible, or
the clamp size. MOdes of vibration and stuff like a M.E. would know. All in order so that the antenna doesn't get blown away in the wind by
pulling out of the joint, or the mast breaking due to encouragement from the design.

Left to right:
-Solid Al. round
-S.S. 304 tube
-Short screw up of something in S.S. that can be turned down
-Upper and lower antenna sections
Al/ clamp (Off of one of those scooters that was junked by a spoiled kid)

DSC_1191.jpg

Opinions on bushing idea, material, length.

Now using half of the original pole that was galvanized steel that rusted through and broke in half.

DSC_1187.JPG
 

EPAIII

Diamond
Joined
Nov 23, 2003
Location
Beaumont, TX, USA
If you are talking about that little, short threaded piece in the first photo, I WOULDN'T. I would suggest at least 6" of overlap and a fitting at each end of that. A full foot would be better.

And are you going to thread the inside of the larger tube? That will significantly reduce it's cross section and therefore it's strength. Again, I WOULDN'T.

Is this going to be a self supporting mast or do you plan to use guy wires? They can help a LOT when the winds kick up.

And why not just get a 10 foot pole? Antenna masts are sold in sections.

antenna mast - Google Search

You are trying to reinvent the wheel.
 

plastikdreams

Diamond
Joined
May 31, 2011
Location
upstate nj
Most ham radio yagi antennas are held together with either hose clamps or sheet metal screws. The tube simply slide into each other, this is for rigidity and for resonance tuning.
 

rons

Diamond
Joined
Mar 5, 2009
Location
California, USA
The larger tube was from a previous antenna with telescoping tubing held with SS hose clamps. Then it fell down in the wind.

No. about the threaded piece going into the tube. The description is that it is just a short piece of scrap that can be reduced down.

The tune is .055 wall. I am using the 7 foot piece with a 3 to 5 piece on top for some reasons.

A good reason is that I can just loosen one connection to remove the antenna from the pole. Or extend it higher.
A bad reason is that I like to use what I already have.
The usual is Cheap, cheap.

I hope this has been interesting to some readers. This antenna height stuff is important, I think when tall trees are in the way. Tall, like in pic.
There is a particular station that is on the fringe and I'm trying to improve on that. That is DEFY that has the Kustom Car program, and knife making
competitions. There is also American Restoration. The other programs like Swamp Things where they hunt crocs and gators, no thanks. They also have one
program where there is wild hog hunting or something, no thanks again.
 

TGTool

Titanium
Joined
Sep 22, 2006
Location
Stillwater, Oklahoma
Gray Hoverman antenna, very interesting. I've done a couple a few years ago but didn't actually watch much over the air so when a storm finally smashed it up that was the end.

Good luck there.
 

rons

Diamond
Joined
Mar 5, 2009
Location
California, USA
This antenna is a modified Gray H. which allows some VHF to have higher gain. Anyway, I designed the hardware so that it can be unmodified.
Hopefully this antenna will have little wind resistance. The days of a big bird Winegard hovering over me.

Mine crashed down but the front V section was totally unharmed, if you don't count corrosion from weather. Some of the reflectors in back were
bent. So I salvage some of those reflector bars and made my DTV antenna. I wanted to flatten the ends of the DTV antenna tubes (just rolled Al.)
so that they would look like a ducks foot (sort of) but I have not figured a way to press the ends and have a sharp looking end. Rather than a
sloppy looking foot stomp.

See this one. With just the front V section (no more reflector elements in back) I can get almost everything. Made with aluminum pieces but held
together with steel rivets that eventually rust away. If they used SS rivets they would put themselves out of work.

HD7694P Platinum HD Series Antenna
 

TGTool

Titanium
Joined
Sep 22, 2006
Location
Stillwater, Oklahoma
Better than my effort it sounds like. I found that the PBS station I wanted most was still broadcasting in VHF and I wasn't picking it up so had to add an additional folded dipole element. All history now.
 

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
You could flatten the ends then cut them with a round wood working chisel. Maybe use one edge of a chassis punch at an angle. For Al a piece of water pipe cut in half at one end and ground sharp might do a few.
Or slip a rubber cap over each end
Bill D
 

EPAIII

Diamond
Joined
Nov 23, 2003
Location
Beaumont, TX, USA
Cheap, cheap, cheap. I should have known it was going to be one of those threads.

My favorite for cheap is PVC pipe fittings. Slap them on the lathe and turn them into the needed bushings. I say plural bushings because I still say a nice overlap of 6 to 12 inches is a good idea.

OR.........

Take a piece (12") of PVC pipe and turn the inside on one end to the OD of the short tube and on the other end the OD to the ID of the larger one. Leave at least 1" at the center with no reductions. With a bit of luck you will have two slip fits and the whole thing stays together via gravity. Should work fine if you use guy wires, as you should.
 
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Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
Antenna masts Around that Diameter have a necked male end roughly 6" long. So I would say your sleeve needs to be 12" long to get 6" on each piece.
Bill D
 








 
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