Re: Topband: DXE Thunderbolt
I had the 18m spiderpole and now I am using the 22m spiderpole. It is guyed with 4x2 guys. It is a stable mast. I raise it by hand by extending the tubes one by one. I would not place the mast over another tube. The tubes cannot handle force from inside. 73 Henk PA5KT Op 7-12-2020 om 13:01 schreef CUTTER DAVID via Topband: Roger Thanks, I had the same idea but I am concerned about the point pressure at the end of the scaffold pole on the inside of the Spiderpole, since on raising and lowering that would be at its extreme.I came to the conclusion of using a "soft" buffer to spread the contact pressure. I didn't think of wood, perhaps pvc drain pipe or the like but I'll look at wood since it can be tailored to fit and I'm only doing it once. The falling derrick is best for me, so conquering this detail is important. What I will never do is drill the f/g pole - that's a quick way to wasting a good pole. This will be a very windy location, so, 3 x 4 guys is planned. I know 2 x 4 guys works for the 18m on its own. David G3UNA/G6CP On 07 December 2020 at 11:35 Roger Kennedy wrote: Well some telescopic fibreglass masts will fit over an alloy Scaffold Pole, so you just slide it over and fit a Jubilee Clip a couple of feet down. Otherwise, it's down to buying some tubing to act as a joining sleeve . . . where the inside diameters are different I have known people use a length of hardwood, and shave each half to the correct inside diameter of the metal and fibreglass poles. 73 Roger G3YRO -- 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 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: DXE Thunderbolt
David I used to do exactly what you asked. I joined a 6m aluminium scaffold pole to an 18m Spiderpole using one of the couplers sold by Barenco https://www.barenco.co.uk/products/brackets-clamps/pole-mounting?v=3610 I raised it exactly as you suggest, with a falling derrick. It took less than a minute to raise/lower it and tie off the guys in the direction of the falling derrick. I suggest that you guy the Spiderpole not far above the coupler. That reduces the stress on the fibreglass in the coupler when it's windy, which is the weak point in that arrangement. I was also careful not to over tighten the bolts holding the Spiderpole in the coupler. It worked well until I moved to the new QTH (a farm) and erected a few towers/masts!! 73, Ian G4iiY -- 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 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector -- This email has been checked for viruses by AVG. https://www.avg.com _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: DXE Thunderbolt
Roger Thanks, I had the same idea but I am concerned about the point pressure at the end of the scaffold pole on the inside of the Spiderpole, since on raising and lowering that would be at its extreme.I came to the conclusion of using a "soft" buffer to spread the contact pressure. I didn't think of wood, perhaps pvc drain pipe or the like but I'll look at wood since it can be tailored to fit and I'm only doing it once. The falling derrick is best for me, so conquering this detail is important. What I will never do is drill the f/g pole - that's a quick way to wasting a good pole. This will be a very windy location, so, 3 x 4 guys is planned. I know 2 x 4 guys works for the 18m on its own. David G3UNA/G6CP > On 07 December 2020 at 11:35 Roger Kennedy > wrote: > > > > Well some telescopic fibreglass masts will fit over an alloy Scaffold Pole, > so you just slide it over and fit a Jubilee Clip a couple of feet down. > > Otherwise, it's down to buying some tubing to act as a joining sleeve . . . > where the inside diameters are different I have known people use a length of > hardwood, and shave each half to the correct inside diameter of the metal > and fibreglass poles. > > 73 Roger G3YRO > > -- > > 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 > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: DXE Thunderbolt
Well some telescopic fibreglass masts will fit over an alloy Scaffold Pole, so you just slide it over and fit a Jubilee Clip a couple of feet down. Otherwise, it's down to buying some tubing to act as a joining sleeve . . . where the inside diameters are different I have known people use a length of hardwood, and shave each half to the correct inside diameter of the metal and fibreglass poles. 73 Roger G3YRO -- 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 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: DXE Thunderbolt
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 > 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
Topband: DXE Thunderbolt
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
Topband: DXE Thunderbolt
David G3WGN, I'm sure you must have some tall trees down there in the Dart Valley! You could save yourself a bundle in shipping charges alone by putting up a simple wire inverted 'L' or a 'T'. Use a pneumatic tennis ball launcher to place the halyard over the tree at the highest point. I have one of these and will even come down and do it for you as you're not far away! My 'L' is 90 feet up and 43 feet out to another tree. It is matched at 1825 KHz by a simple 1,600 pf high voltage ceramic capacitor as an L-network from base to the radial field. These caps are hard to come by these days, so rather than making the antenna slightly longer and inductive, it is probably better to make it slightly shorter and capacitive and then matching with a small shunt inductor, known as a 'hairpin'. Look forward to hearing you on 160! 73 Tom G3OLB _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
