[Elecraft] E-H Antenna Simulation in NEC

[Stuart Rohre]

John, a clarification please,  certainly the efficiency of the large
cylinders is large, taken as themselves alone, right?  That is the 98 per
cent efficiency you quote?   Because of the losses in the matching network,
(practical network which surely would have a Q of far less than 1000, )  you
then see the overall antenna efficiency as only 1 per cent, correct?  IE the
antenna has to be taken as a system and the inefficiency of the matching
detracts from possible efficiency of the whole.

The standard method of measuring small antennas is a Wheeler cap, a closed
cylinder that can be placed over a test antenna above a ground plane.
Measurements of Z of the antenna with and without the cap can be entered
into calculations to produce efficiency based on the low radiation
resistance component of Z, and the high loss resistances of the antenna
system.  We have such a Wheeler cap at work, and are measuring locally
produced FLEX antennas.   I hope to use the cap after hours someday to
measure an EH for which I collected parts.

Thanks for doing the modeling, it is very informative.   Very low radiation
resistance is a big hurdle, but even dummy loads radiate some.
73,
Stuart K5KVH