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SOTApole question

For over a year now I have been using a SOTApole and 144MHz 5 element SOTAbeam. As the beam uses a plumbing U clamp rivetted to the boom, it always mounts on the pole at the same height. Recently I have noticed the pole is beginning to crack at that position. So does anyone know how I can reinforce / strengthen the glass fibre without affecting it dimensionally, i.e. without thickening the tube?

73, Gerald

In reply to G4OIG:
I find the same thing Gerald. At £10 each, I find it easier to replace the pole for a new one, after all over a years service isnt too bad. My problem is the screw on base cap, these seem a lot more brittle than they used to be hence why my poles normally sport a duct tape decorated base cap. Steve G1INK (It wasnt my mobile phone)

In reply to G4OIG:

Get a piece of the plastic tube used for waste overflows, slide it down the tube to where it lodges, and clamp to that point - cheap and cheerful!

73

Brian G8ADD

In reply to G4OIG:

Too late now gerald, but sticking a piece of sticky sponge/foam draft excluder around the inside of the clamp helps a lot with the Sotabeam mount bracket, maybe it will prevent the cracking caused by your beam?

73

Mike

In reply to G4OIG:

Gerald,
reinforcing the inside of the tube with resin & fiberglass would strengthen it as much as you like, but the top sections of the pole would not fit inside anymore.

If this is what you want:

Protect outside of beam with sticky tape. Sandpaper inside, cut fiber tissue, wet tissue with resin, place inside tube avoiding air bubbles and excessive resin as much as possible. I would thicken by 100%, more tissue were the bracket sits, less towords both ends (force distribution). When finished, place long (not round) ballon inside reinforced tube and pump it up, leave until resin is hard. This will press additional resin and air bubbles out and strenghten the structure. Work and let resin get hard at room temperature for best results.

Regards,

Gerd DF9TS

Many thanks for all the suggestions. Being Mr Scrooge, I would like to get two seasons out of it (Hi), so maybe just reinforcing it with resin will help it achieve that. I will measure the outside diameter of the tube at the position where it is cracked and also the top of the section below to see whether I can increase the diameter a bit and still allow the sections to slide and lock together. It would be a pity to lose the ability to use the higher sections.

If this method of repair is successful, then the beam will sit above the repair and be a relatively loose fit, so I will need to install a pin to lock the two together. Perhaps I should have done that in the first instance so the beam didn’t need to be a tight fit to the pole.

73, Gerald

Gerald,

Why not do a 2nd activation of a ‘relatively’ near summit, and use the fuel savings to buy three spare SOTA poles?

Idea of the Day :wink:

Tom M1EYP

In reply to M1EYP:

You’re ‘avin’ me on mate! Tantamount to being like a red rag to a bull that sort of comment. How do you know I’ve found one I want to go back to anyway? I might be still looking! Hi Hi.

Good to work you and Jimmy on Saturday.

73, Gerald

In reply to G4OIG:

In reply to M1EYP:

You’re ‘avin’ me on mate! Tantamount to being like a red rag to a bull
that sort of comment. How do you know I’ve found one I want to go back
to anyway? I might be still looking! Hi Hi.

Good to work you and Jimmy on Saturday.

73, Gerald
Hi Gerald Another method of strengthening the tube would be to sleeve it over the top of the area in question with a short piece of tapered tube off another scrap mast,( I may be able to give you a piece if you tell me the size you require).I am lucky enough to have some lathes so I have made mine from aluminium taper bored to suit the mast and parallel on the o/d to suit the bracket on the mast.All the best Geoff

In reply to G6MZX:

Hi Geoff,

Thanks for the suggestion. That solution should work out well. The mast is 20 / 21mm OD where the crack is - around 110mm in length. With 1mm thick tubing from a gash mast used as a sleeve it should easily go through the next section down which is around 25mm ID at its upper end. I suppose the other alternative is to force resin into the cracks and tape it over for extra strength. This would need to be done carefully to be effective. I am sure that I have caught this before it it becomes “terminal”.

Good to work you on Saturday.

73, Gerald

Just a brief note to say that a coating of Araldite rapid sealed in with electrical tape wound tightly around the affected part just before the resin set affected a strong repair.

Scrooge Tip -

The SOTApole has continued to be in the wars. Murphy’s Law applied on the last activation when I unfortunately lost the rubber bung from the end of the pole - well it has lasted almost 18 months! The rubber bungs are impossible to obtain, so for those of you that have poles lying around for want of a bung, a decent job can be made using the top from a plastic milk bottle. I cut the top 25 - 30mm off the bottle giving me the threaded section and a plastic skirt. I carefully cut slits in the skirt so it could lie flat against the pole, used a length of jumbo tape to slightly increase the diameter of the pole, slipped the bottle top over the end and used more jumbo tape to fasten it to the pole. Screw on the milk bottle screw cap and the pole is back in full working order. A milk bottle screw cap can also be used as a replacement for the bottom screw cap, but it needs a bit of force to get it to fit as the thread is coarse and it needs to be taped to secure it.

73, Gerald