Reg:

I'm primarily doing the US MIL-STD-461E protocol, on widely varying
test
specimens (hand-held, man-worn, 2-meter tall racks, 2-meter diameter
parabolic tracking antennas), so I am getting my antennas calibrated
for 1 &
3 meter separation distances.

The lab I use has an outdoor range, and I get a Certificate of
Conformance
for each antenna which includes the following statements:

"Test and Measurement Equipment used for performance verification is
calibrated with traceability to the U.S. National Institute of
Standards and
Technology. Inspection records, test data, and other evidence of
conformance
are on file at the sellers facility are are available for inspection
on
request."

They further state a "Calibration Uncertainty of (2 sigma) (+/- 1
dB)" and
reference "SAE ARP-958". I then get a listing of the specific
instruments
used in the generation of my antenna data, along with their
calibration
certificate numbers and the date of each calibration period
expiration.

As for the data, I get a tabulation and a plot. For a typical
antenna (an
EMCO 3115 double-ridged horn covering 1 GHz to 18 GHz), I get a
tabular
array of antenna correction factor, dB return loss, SWR, numeric
gain and
dBi, in 250 MHz step increments, across the range. I also get a
continuous
swept plot of return loss, and from this, I infer that the lab uses
my
unknown antenna as the transmitting element on their range.

This data and the C of C is enough to keep my internal Metrology guy
happy,
and it gives me a sufficiently warm feeling. I have been using the
same
antenna lab for almost 10 years, and I informally track the
calibration data
from year to year on each of my antennas. So far, the data never has
looked
"copied", fudged, or otherwise egregious. However, that may just
mean I'm
easily fooled.
--
Ed
WB6WSN
El Cajon, CA USA

============================================

Much obliged to you Ed for interesting infomation from a reliable
source.

Including 2-Sigma uncertainty limits of +/- 1 dB.

Thanks.
Reg, G4FGQ