[Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Andy Durbin]

"although I saw a design not long ago that used two coaxial copper pipes with a PVC pipe as the insulator.  The inside conductor was mounted to a long threaded rod moving it in and out of the outer conductor."

Not my original idea but that's what I have on my loop (PEX insulator not PVC).  Works fine up to 100 W on 30 m but has SWR runaway at 150 W.   Capacitor is driven by a geared DC motor and is tuned from the shack.  Home brew is far more fun than buying commercial.

I'll post a link to a presentation if there is any interest.

Andy, k3wyc