In persuit of the BPL issue, I have explored small untuned loops for
field strength measurement.

Comparison of a loop calibrated to an NEC2 model to a commercial loop
with traceable calibration was very encouraging.

Constructors would like to use insulated wire for such a loop, and that
raises the question of the effect of insulation on the Antenna Factor.

My guess is that where the loop is small, current is uniform and the
effect of a slightly different phase shift around the loop due to the
insulation would be very small. That would be less so at frequencies
approaching the first resonance of the loop.

My understanding is that NEC4 might provide a good estimate of the
difference between insulated and uninsulated wire. I don't have NEC4 and
am looking for someone who might be prepared to run a bunch of models for
me in batch mode. I would supply the model decks and a batch file to run
them, my volunteer would need to run the batch file and zip the output
files up and mail them back to me for analysis.

My intention is to produce the same data that is plotted at
http://www.vk1od.net/SmallUntunedSquareLoop/ssulNEC.htm for each loop,
and to plot the dB difference vs frequency to infer some general guidance
on loop sizes where conductor insulation becomes significant to Antenna
Factor.

Comments / volunteers?

Owen

owen at vk1od.net