Looking For An Alternative to a Fiberglass Rod.

In the fire service, fiberglass poles of 1.125 " are used as poles to check for fire extension in ceilings. They come in lengths of 6' to 14 ' commonly. The price for the pole with the steel ends riveted in place is only around $125 US. The price for the FG pole alone should not be that much. Fire departments pay dearly for products for their line of work. You could always go to wood.One 2 x 4 should be able to be turned down into two poles of your desired dimension. I would pick a harder variety for more strength. Good luck.

Need more info.

How much weight?

Insulation properties?

UV resistance?

Any mods to rod? holes? or cut to length?

Can a larger diameter be tolerated?

Any specification requirements FCC/MIL/FED STD, FED SPEC, Commercial

Current source?

Have you consulted current supplier?

Or is it just "same as G10"?

The more information you give us, the more informed the answer will be.

Weight is Minimal, less than 10 pounds.

Insulation properties, Peak voltage on it will be close to 400 volts.

UV preferred, but will accept non also, since most if not 99% of the rod will be inside the radiating element, and or the lower mounting tube. maybe 1/4' will be exposed.

No holes, and yes cut to length of about a foot..

Larger is a possibility,, if the price doesn't get too crazy.

sure on the G10,,

But anything similar would be just fine also, as far as strength,, it is going into a piece of 6061-T6 1.25 od 0.058 wall, and this tube has never even come close to bending under the stress, as a semi guideline.

Joe

Contact all the local fire departments you can. Ask for their damaged old pike poles. They may give you the old ones when they change the ends out.

"But anything similar would be just fine also, as far as strength,, it is going into a piece of 6061-T6 1.25 od 0.058 wall, and this tube has never even come close to bending under the stress, as a semi guideline."

This opens many possibilities. I'm sure you will see some enlightened responses, soon.

Since we are a curious lot, there may also be other questions. Such as, You don't care about the .0045 in. gap? You don't have to answer that one.

Good luck

LL

Since we are a curious lot, there may also be other questions. Such as, You don't care about the .0045 in. gap?

That brings up another question: Is the fiberglass just an insulator, or a dielectric, or both? Using a different material could give a different capacitance, and that could affect the tuning.

Strictly an insulator, there is no overlapping of the lower mount and the uppeer tubing.

Yes there may be a small amount of cap due to close proximity, but so small it's not even worth thinking about.

That small amount of slop is a good amount for the 1.25 OD 0.58 wall to slide over the 1.125 od rod.

The lower portion of the tubing is slit 1 inch and a stainless hose clamp is all that's needed to hold it in place on the rod.

If this is to be mounted inside another tube, then why not use PVC or similar tube for the ID and then have it hollow?

Could then even allow you to fit core material if that would provide benefit.

Nope,

It would be as if you were seperating two pieces of tubing,, no overlap of any metallic parts.

From your description so far, I understand that you currently form the antenna over a fiberglass rod and then insert that inside the other rigid tube.

What I am suggesting is that instead of a solid rod for the core of the winding, that you may consider a tube of insulating material.

There are available (very cheaply) PVC tube used in plumbing or underground cable instalations that are close to the size that you nominated.

Would that be suitable?

I also guess that the antenna is "directional" along the axis of the rod/tube assembly, since the outer metal tube would significantly affect any radial signal. If you use a tube as the former/bobbin for the winding it would then be possible to introduce a core material to further enhance the electromagnetic effect of the antenna.

Basalt rods are available from Sudaglass.

www.sudaglass.com

also Kammenney-vek www..basfiber.com

If you are in UK look at Rockbar

If in Austrailia Lance Brown exports

The alternative that comes to my mind right away is Carbon Fiber material. I don't have experience with it, and it may be cost prohibitive, but it would most likely be strong enough for your application, and would insulate well.

Nope carbon fiber is conductive (very) and is also prone to cause galvanic corrosion with Aluminum.

3/4" PVC or ABS conduit is 1.05" o.d. and .824" I.D....

You could use Delrin it is hard but easily machinable.

Torlon works well too. A bit pricey, but it'll handle anything you can throw at it. I've used it to insulate 140 kV RF induction furnace coils.

US Plastics at www.usplastics.com has PVC, Polypropylene, CPVC, Cast and Extruded Acrylic, Polycarbonate, and at least ten other options. There was another plastic company that had more choices, I think it was San Diego plastic.

But I still do not understand what is wrong with wood, unless you need a solid component, not hollow.

I'd bet the issue is water absorption and rot over time.

Have you considered a foam core?

Jam a piece of PE foam in it or foam it in place.