Don't quit posting Jerry, you are an asset to the group.
It is just that courtesy is not a requirement in this group
so some posts tend to be a bit sharp and personal
Look forward to hearing from you again
Regards
Art






"Jerry Martes" wrote in message
news:xNr4e.3912$%b1.1814@trnddc08...
Roy

I make no claim to being qualified to discuss antennas with you when we
are in disagreement. I worked as an antenna design engineer for 15
years till 1968 when I was layed off from TRW. I was never a high level
theorist but managed to hold a decent position with designing hardware. I
did work with some highly qualified engineers from whom I thought I
obtained alot of knowledge about antennas. Thats why I was bold enough
to say "we". I still maintain a casual relationship with George Oltman
who you might know from his association with antenna groups with IEEE.
As for the F/B, I considered that to identify Front to Back of the
antenna's radiation pattern. I would consider it appropriate to identify
the radiation toward the "Front" as the max radiation to the front. Then,
it seems that the numerical level used for the "F/B ratio" should be max
to the Back.
I make no argument that this definition I use is *the* way F/B is. But,
dont we define "side lobe level" as the ratio of the main beam Max to the
side lobe Max? Be aware, I dont write to correct your thinking. I did
consider the F/B to be flawed when the main beam Max is compared with a
rear radiation Min.

I'll consider myself corrected and stop posting.

Jerry

"Roy Lewallen" wrote in message
...
What are "front" and "back"? If the maximum forward lobe is +10 dBi at an
elevation angle of 23 degrees and the best null is -30 dBi at an azimuth
angle 160 degrees from the peak forward lobe, and at an elevation angle
of 47 degrees, are you saying that by your definition the front/back
ratio is 40 dB? If so, I guess that's interesting but I can't imagine
what it might be good for.

Who's "we"?

Roy Lewallen, W7EL

Jerry Martes wrote:
Roy

When I was working with antennas, we considered the antenna's F/B
ratio used the max of the front compared to the max of the back. But,
I get the impression that the rules are different now.

Jerry