Haven't said a blessed thing about your radials, which will make or break it. Someone talked about a problem with using a SteppIR on top of a loaded tower. Been a while and don't recall the particulars, probably should search the archives.
73, Guy. On Sun, Apr 3, 2011 at 12:29 PM, Jerry Keller (K3BZ) <[email protected]> wrote: > I want to try a shunt feed on my 60' aluminum freestanding tower topped with > a 4 element SteppIR. The tower is a Heights and it tilts over on a 4' high > top-hinged base. I've come up with the following specs I dug out of K1ZM's > book "DXing on the Edge": > > (1) Three #14 stranded insulated wires spaced 15" from tower leg and shorted > top and bottom as an 8"-on-a-side triangular cage, running from top of tower > down to where the tower joins the hinged base (4' above earth level because > of the hinge). That would make the shunt 56' high. > > (2) I'd like to use an omega feed with air variable caps I liberated from an > old tuner. I notice that most often vacuum variables are used for this > rather than air variables. The plates in the air variables I have are spaced > about 3/16".... will they handle a KW without arcing? > > (3) I want to put the feed caps in a plastic box at the 4' level so the > shunt won't interfere with tilting the tower over. The tower grounds and > the radial system would connect at ground level to a flexible copper line > running from ground level up to the feed box. Would that work OK at 160M? > If it's important, I could run the shunt the full 60' down to ground level, > but it's mechanically more difficult. > > (4) With this arrangement, how important is the SteppIR? Would I need it for > top-loading? The SteppIRs elements "float" above the grounded boom... > should I plan to ground them to the boom? > > Advice, alternatives, comments? Any input appreciated. > > 73, Jerry K3BZ > > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
