Aluminum Round Tube 6061-T6 1.500 OD. X 0.250 Wall thickness for 18’ 6” to 20, antenna mast. What do you think?

[63Sprint]

I have an opportunity to purchase a 24 foot length of Aluminum Round Tube 6061-T6 1.500 OD. X 0.250 Wall thickness for 18-1/2 foot antenna mast. I was reading that the the antenna might possibly act as a dipole if the pole length is the same length of the antenna. Is this true.?

I am able to store a 20 foot length of this tubing under the trailer strapped to the frame with no issues. I believe it’s seamless tubing.

Does anybody know how strong it would be? Im thinking of making two rigid guy struts that will mount 10 feet up on the pole. And, the guy poles will mount directly to the outside front corners of the trailer frame. The guy poles will have adjustable tie-rod ends so the antenna can be easily adjusted and kept plumb. So, in theory, there will be a rigid triangular structure holding the pole. I’m thinking that this setup might hold up to just about anything that we might see. I figure that it will take more abuse than what the antenna is capable of handling.

The tubing is at a friends shop and I can get it at the fraction of original cost. A 20 foot length weighs 23 pounds.

If this pole is way bigger than what I need there is also a 20 foot length of
Aluminum Pipe 6061-T6 1.000” Schedule 80 (1.315 OD X 0.179 Wall )
around 15 lbs. On the plus side of the 1 inch SCH 80 pipe, it’s about 8 pounds lighter. That is a huge difference in weight. And it will be much easier to put up.

Please give your thoughts and opinions.

Thanks

 

[prcguy]

If an antenna is not adequately decoupled from the feed line or mast they can become parasitic radiators. The Antron A99 and a few others are notorious for this. I think a 9ft or 1/4 wave resonant length of mast would be more of a problem being very low impedance on one end where an 18ft mast would be 1/2 wavelength long and very high impedance trying to couple “loose“ RF into the end.

Why not look at thick fiberglass telescoping mast sections, you should be able to get something like a three section that is maybe 7ft collapsed and about 20ft tall extended and very light weight. I would try for a top section 1 1/4” to 1 1/2” dia or up to whatever’s the largest size your antenna can take.

Here is one that is 25ft and collapses to about 4ft and has a 1” dia top section. You can build them any way you want with less longer sections and larger dia top sections. One nice thing about using insulated masts is you can put a good choke balun at the antenna connector and there is no metal mast to become a parasitic radiator.

DX Engineering DXE-TFK25 DX Engineering Complete Fiberglass Tubing and Cam Lock Clamp Kits | DX Engineering

Free Shipping - DX Engineering Complete Fiberglass Tubing and Cam Lock Clamp Kits with qualifying orders of $99. Shop Fiberglass Tubing Kits at DX Engineering.

www.dxengineering.com

 

[63Sprint]

I’m a little lost, I thought an aluminum mast would be a good thing for the ProComm, Proton, PT99. 1/2 wave antenna.

I see I have more to learn because I don’t understand what would be best.

The aluminum tubing would cost me $40.00. A friend has had it in his garage for over 20 years. But if it won’t work I won’t bother with it.

You mentioned that the antenna has to be decoupled from the mast. I’ve seen insulated mast/antenna clamps. Is this what is used? Or, it will still not be good enough?

Would these work to decouple the antenna from a mast?

DX Engineering DXE-RSB-I11500 DX Engineering Resin Support Block Clamps | DX Engineering

Free Shipping - DX Engineering Resin Support Block Clamps with qualifying orders of $99. Shop Resin Support Block Clamps at DX Engineering.

www.dxengineering.com

 

[63Sprint]

One nice thing about using insulated masts is you can put a good choke balun at the antenna connector and there is no metal mast to become a parasitic radiator.

prcguy,
Is it possible to explain in simple terms what you wrote. I’m embarrassed to say that I do not understand what you wrote.
I’m really see how much of a novice I am with antennas. I thought it would be easy to put one up. And now I see that I pretty much know very little on properly installing an antenna.

 

[63Sprint]

Well, this is a start.

Ferrite Toroid Baluns - John Portune – W6NBC

Few hams have a clue of how to select a toroid and wind it to make a 1:1, 4:1 or 9:1 balun and the well-known radio books can be confusing. This presentation...

www.youtube.com

 

[63Sprint]

Here are a couple more clips:

 

[slowmover]

My budget has been too constrained by vehicle repairs to continue several radio projects at present.

Antenna Feedpoint Coax Choke

Feedpoint Choke Mobile, it’s a nicely impressive addition to add a feedpoint choke in my experience. Reduction of CMC with another coax choke at transceiver end. I’ve used a somewhat expensive version that’s been difficult to mount on the exterior of the big truck. Time for simpler. Buried...

forums.radioreference.com

At radio end used @prcguy recommendation of:

CMC-130S-3K 1-30MHz – MyAntennas.com

Plus

Toroid wound for antenna feedpoint per ferrite cookbook and advice seen in thread.

Devices I’m replacing prove this SNR approach to both coax ends being worthwhile in my experience in mobile. I’ll also be applying it to my RV portable set-up, as well as to my pickup.

Small Base Antenna: SIRIO Boomerang W

Each leg about 4’ plus or 9.4’ total https://unicomradio.com/product/sirio-boomerang-w-base-antenna/ Forgotten I had one of these. Am going to be home long enough it’s worth the trouble to me to get a 5-gal bucket holding a painters extendable pole to run it up a ways. Similar to this...

forums.radioreference.com

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