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 <[email protected]> > 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 > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
