Re: NEC-LIST: Definition of Gain

George,

Thank you for initiating the long overdue discussion:

1) Should stay seperate: And regarding practical measurements - we
painstakingly remove the mismatch loss from two antenna gain
measurements to get the "textbook gain". I have had arguments about
doing this so can understand the "practical" dislike. For example: A
person comparing A and B and finding A gives a higher received signal
when linked to rx or spectrum analyzer. A recommendation is to refer
to the combination of mismatch loss and gain as the "matched gain",
meaning the apparent gain when linked to a receiver which is nominally
matched to the antenna.

2) Definitely should stay out of the gain definition as seems to be
the consensus.

3) Definitely the same.

A related issue (in terms of definition of gain):

Most textbooks refer to gain and directivity as the maximum intensity
of the radiation pattern. This then (in theory) does not permit a plot
of gain versus angle and does not allow us to say the "gain of the
antenna 10 degrees of its axis is 22 dBi". We do this all the time (I
believe) and do not use gain only to refer to the pattern maximum. We
have to use english terms like "directive gain" to refer to the gain
of an antenna at points other than the maximum (which seems to lead to
"directive directivity" by analogy). Can we not simply refer to:
maximum gain and gain as well as maximum directivity and directivity.

Regards
Andre Fourie

Tel: Intl + 27 11 4030380
Fax: Intl + 27 11 4030381
Website: http://www.poynting.co.za
email: fourie_at_poynting.co.za
Papermail: Dr APC Fourie, PO Box 318, Wits, 2050, South Africa
Received on Tue Mar 07 2000 - 04:26:57 EST