Re: NEC-LIST: Electrically "short" antennas ...

From: D. B. Miron <dmiron_at_email.domain.hidden>
Date: Thu, 11 May 2000 08:22:29 -0500

Good day Doug,

    Did you do anything to suppress the reflected wave on the outside
of the coax? Because of the impedance mismatch between the small
antenna and the coax, there is a reflection, part of which will travel
back inside the line, but part of which will go along the outside of
the shield and radiate. Many small antennas have had better than
esxpected performance because it was actually the coax that radiated.
Did you use a "ground" plane or just the open end of the coax? What
structure did you use to hold the coax-antenna assembly?
Unfortunately, tests like this are very sensitive to environmental
details. The performance described in a textbook is usually in an
empty space with a source right at the antenna, no big box, no
transmission line. Give us more details, and we might be able to give
you more answers.

Doug Miron
Received on Sat May 13 2000 - 11:05:04 EDT

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