I have been working on the BPL Interference issue.

One of my projects has been exploring ways by which ordinary (well,
competent anyway,) amateurs can make reasonably reliable measurements of
noise / interference using existing amateur station equipment or
equipment that is easy for amateurs to construct.

This has led me to search for a portable antenna of reasonably
predictable gain that can be used with a known HF SSB receiver.

I have had a hack at predicting the gain and antenna factor of a small
square untuned loop driving a 50 ohm load. The model is in a Mathcad
worksheet, but I have copied it to a gif file which you can view on my
website at http://www.vk1od.net/bpl/loop.mcd.gif . (The worksheet is
entirely in metric units.)

I would appreciate any comments / review on the model and calcs.

Owen