Further to that scheme, is there a sound way to join a Spider pole to a
scaffold pole? The cost change from 18m Spider to the next sizes up is quite a
jump, but I've often thought an alloy scaffold pole at the base would be worth
the effort if I had a decent way to join them. I can raise the 18m Spider pole
using a falling derrick on my own and a rigid extension underneath looks doable
with help.
David G3UNA/G6CP
> On 06 December 2020 at 18:55 Roger Kennedy <roger@wessexproductions.co.uk>
> wrote:
>
>
>
> David I'm inclined to agree with the other Gs . . . you could do this MUCH
> more cheaply yourself (maybe a tenth of the cost) . . . and probably make a
> stronger and more efficient antenna.
>
> 21ft thick-walled alloy scaffold aren't that expensive, yet are extremely
> strong . . . and if you see a scaffold van parked, ask the driver how much
> he could let you have a couple for (I think you'd be surprised!)
>
> Clamp 2 together, and add another 21ft normal thickness pole on top
> (obtainable from any TV aerial company).
>
> Then increase the length with a horizontal wire section, to get it resonant.
>
> Personally, I wouldn't even use the poles as the radiator . . . easier to
> just run a thick wire from the top to a couple of feet out from the bottom .
> . . if you want to increase efficiency use 6 wires in a cage.
>
> And if you do that, you could use a fibreglass top section - old Windsurfing
> masts are cheap as chips on eBay and VERY strong ! (I still Windsurf, so
> have several of these)
>
> 73 Roger G3YRO
>
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