Here's a brief write up on Greg Mihran's presentation (attached). ?Many POTA enthusiasts describe the POTA PERformer as a game changer. ?What struck me about Greg's work is his attention to both antenna modeling and field measurement.
?
For example many amateurs have been told that ground plane radials should be 1/4 wavelength long but by measuring the current flow on the radials he was able determine this is not optimal. Proximity to the ground detunes the radials lowering their resonant frequency so the point of maximum current is pulled away from the base of the vertical into the ground increasing losses.
?
Another novel concept is measuring how counterpoise length can affect the resonance of an end fed half wave. ?Most of us have been told the outer shield of the coax can serve as the counterpoise and the length doesn't matter but that's not necessarily optimal. ?When I'm operating portable I want the most efficient antenna system I can transport and setup easily.
?
Bring your antenna questions and enjoy!
?
73, Peter K1AV
?
?
Peter Sichel K1AV