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Old February 20th 08, 10:40 AM posted to rec.radio.amateur.antenna
Richard Harrison Richard Harrison is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 588
Default Horizontal loop antenna

Roy Lewallen wrote:
"Perhaps you build antennas for radiation resistance, but I think most
people build them to maximize radiation in some particular direction.."

You must have some radiation resistance or you have no signal, but not
all antennas are highly directional.

Page 8-10 of the 20th edition of the ARRL Antenna Book has (Eq 5):
Efficiency = radiation resistance / radiation resistance + loss
resistance

Zero radiation resistance = zero efficiency.

Best regards, Richard Hsarrison, KB5WZI