On Thu, 17 Jul 2008 20:30:48 -0500, Bob Bob
wrote:

Hi Richard

Isnt there a difference there? (I'll admit I dont think in these terms.
I use the actual pattern instead)

Isn't F/B a comparison of "forward" vs "backward" at the optimum/best
case "single angle" and Back Rejection (or some other name) the
comparison of all radiated power forward vs backwards?

Many parasitic designs end up with very good F/B but as soon as you go
off a few degrees a rearward lobe comes into play.

Cheers Bob VK2YQA

Richard Clark wrote:
What's the difference between FRONT TO BACK RATIO and BACK REJECTION?

Hi Bob²,

If you examine the specifications for both, they reveal exactly the
same value. It follows they measure the same thing but use different
terms (one can only imagine they have ad writers who find their
inspiration for straining terms in claims for Gussian antennas).

There are very few antennas with a null located at 180° (Cardioid
comes to mind); and, as you infer, it quickly disappears off
boresight. Further, your suggestion of average forward compared to
average backward is, perhaps, a useful indicator. However, neither
supplier appears to interested in averages.

73's
Richard Clark, KB7QHC