Richard
That rule is not all encompasing tho it may well suffice for yagi's and the
like
Regards
Art
"Richard Harrison" wrote in message
...
Jerry Martes wrote:
"When I was working with antwennas, we considered the antenna`s F/B
ratio used the max of the front to the max of the back. But I get the
impression that the erules are different now."

Front-to-back ratio is defined as the ratio of power gain between front
and rear of a directional antenna.

A.W.P. King writes on page 209 of "Transision Lines, Antennas, and Wave
Guides"*:

"In practice, it is usually important to maximize the ratio of forward
to backward field or the ratio of backward to forward field. If the
ratio of forward to backward field is maximized, the parasite is called
a reflector; if the ratio of backward to forward field is maximized, the
parasite is called a director."

I don`t think the above has changed since 1945.

Best regards, Rihard Harrison, KB5WZI