[TenTec] Big TX Loops

[Merschrod]

as long as we are OT - look up VE3UK  on qrz and follow his Loop pages.

Super nice machine work and also metal work.

73,  Kris KM2KM




















> My neighbor, W6GJB, has built a large TX loop Here's how described it to
> another ham. The "army mast" he's talking about is a bunch of 4 ft
> sections of 2-in o.d. Al tubing that fit together, and fit into a
> triangulsr base. They've been sold at Dayton and other flea markets for
> several decades, and are quite useful. With a tripod section made from
> two sections per leg, it's easy for one guy to push them up, then slip
> another section under it at the bottom, and so on They will, for
> example, support a small tribander like a C3 at 30 ft if guyed properly.
> We've also used them to build a 2-element vertical array for 40M.
>
> =   =   =   =   =   =   =
>
> The mag loop is homebrew, made of 8 segments of Army mast bent (very
> carefully) in a pipe bender.  The whole thing can break down and go into
> the big green bags that go with that tubing.  The air-variable capacitor
> should be able to handle 500W, but I have not tried that yet.  Running
> 100W at this point with a KX3+KXPA100.
>
> With 8 segments it is close to 1/4 wave on 40, which should be over 90%
> efficient with some of it going into low angle radiation.  Should be
> better than a low dipole.  I can add fixed capacitance to tune it on 80,
> or add another 4 tubes and it should be better than 80% efficient on 80.
>
> =   =   =   =   =
>
> So to clarify, his loop consists of four sections of mast that are each
> bent twice at 45 degrees. They go in the four corners, then a straight
> section goes between each of the four sides. That's the 40M loop. So
> what he's saying is that to build it for 80M, you simply add another
> straight section on each side.
>
> This is a current project for him, and he's in the process of on-air
> testing using RBN to get comparative signal reports with his other
> antennas.
>
> This is fairly inexpensive to build (I'd guess around $500), but you
> need a good pipe bender, some practice, the sections, and suitable HV
> caps. I've given him several big air variables from my junk box to play
> with.
>
> An objective is for something he can throw in the back of his truck and
> set up quickly for FD or CQP.
>
> 73, Jim K9YC
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