Anyone have an answer to Steve's question about whats better; stranded or solid wire? Thanks for the help.............Larry
Hi L,
I spent some time talking with a guru who used open wire to inter-connect his massive 450mhz Yagi array. It works very well for him. (see another post I made a month ago)
He said that on VHF/UHF you don't want to use bare copper cuz of the surface corrosion and poor conductivity due to skin effect. On VHF+ the RF currents would be flowing mostly on the surface thru this crud.
But, on HF, the penetration is deeper into the copper wire and the surface crud becomes a smaller percentage of the path. On 160-40M I wud think it's a non issue, though it's all a matter of degree and how anal you are.
He suggested using double coated enameled wire for the feeders to keep the copper clean inside. You might also wonder about using the common PVC covered wire. Evidently there are dieletric losses using that above 20M or so, but again, 160-40M should be OK and a matter of degree. I've used it for years on HF.
As for stranded or solid, it makes no difference on HF, though he recommended to use solid on VHF/UHF for whatever reason. Maybe cuz enamaeled wire is usually solid or maybe solid is smoother for RF skin effect, dunno. (that almost sounds like an audiophile oxy-free type comment, huh? :-))
I've used simple PVC tubing, the gray 1" diameter gray stuff in the electrical dept at Home Depot for speaders right up to 20M. Cut them into 5-6" lengths, drill holes and slip them onto the pair of wires. Stretch the open line out TIGHT between two trees and then tie the spreaders on with #14 SOLID insulated copper wire. I usually use PVC covered black #10 stranded wire for both feeders and flat top on HF. (Home Depot, 500' roll - cheap)
Those fiberglass reflector sign rods are FB too. I've used them for Yagi center el sleeves on 6M. Most any good insulator material is OK on HF as long as it is UV resistant. Watch out for some nylon stock that turns to mush in the sun. Also, paint the ends of your fiberglass rods to keep water from wicking in. Once the outside glaze is broken it becomes vunerable according to a fiberglass guy I know.
73,
Tom, K1JJ