Very interesting post Reg
I see gain figures in Db alone as misleading
since one isn't aware if lobe thickness ( and elevation angle) is taken into
consideration.
As Ian points out, comparison to a dipole is fatal since comparison of max
gain inevitably
involves different angles of elevation ( I assume that labs take this into
consideration
but I have no proof of it.) As I have stated in the past, different antenna
designs provide
different lobe thicknesses, such that comparisons with each other can
provide higher antenna
gains to the lab's whim if the elevation angle is not taken into
consideration.
Taken to the extreme, all antennas with the yagi design can be declared
equal in gain
when measured at the elevation angle where the leading lobes intersect
Regards
Art


"Reg Edwards" wrote in message
...
All electrical calibration and testing laboratories issue tables of
claimed accuracies of measurements. Measurement uncertainties stated
on calibration certificates are legally binding. All stated
measurement results must be traceable to International Standards or a
laboratory or testing station loses its status.

Consequently there is no incentive for a laboratory to overstate its
capabilities in its sales literature. Indeed, it is dangerous,
illegal even!

Naturally, laboratories can differ widely, one from another.

It would be interesting to compare laboratory uncertainties with
performance figures claimed by antenna manufacturers. Or anyone else.

Does anyone have typical examples of measurement uncertainties claimed
by antenna testing stations? Answers in decibels please.

A reply from a testing station, at HF or VHF, would be specially
appreciated.
----
Reg, G4FGQ