"Richard Harrison" wrote in message
...
Art Unwin wrote:
"Has a graph been made based solely on NEC program findings over say a
perfect ground and at a uniform height?"

I don`t know,

Neither do I thus the question

but I`ve seen Yagi-Uda gain versus boomlength charts.

So have I but not based on NEC


Before relying on such charts, it may be worthwhile to read "The
Yagi-Uda Story" on page 246 of the 3rd edition of Kraus` "Antennas".

Also, the solution to a Deutsche Welle Short Wave Antenna problem on
page 703 is given on page 705:

"the gain of a single 1/2-wave dipole is 2.15 dBi and of 2 collinear
in=phase 1/2-wave dipoles is 3.8 dBi. The array of 8 such collinear
dipoles adds 3+3+3=9 dB. The reflector screen adds 3 more and the ground
bounce another 6 dB for a total gain of 3.8+9+3+6=21.8 dBi or a
directivity of 151 approx."

The above extract is lost on me as I was looking for maximum gain per unit
boom length based on NEC without regard to number of elements
required to attain that gain. Thus increases or decreases from critical
coupling
can be ascertained..

Art


The solved problem is worth the price of the book as a reality check.

Best regards, Richard Harrison, KB5WZI