RadioBanter - View Single Post

February 4th 04, 08:56 PM

On 4 Feb 2004 00:36:07 -0800, (Maurizio) wrote:

A 6dB discrepancy is a human problem, and glaringly evident.

73's
Richard Clark, KB7QHC

Hi Richard,
I agree that the human factor can be the problem for this discrepancy,
however, it would be also very interesting to know about other
experiences with such type of measurements, just to narrow the
expected uncertainty window.
(Better if in presence of complex environments)

Maurizio

Hi Maurizio,

This is best achieved by establishing a standard with as few variables
as possible, then varying them to determine their range of error
contribution. I am sure this is already evident to you, however
experience in going through the tests can reveal how probable those
sources of error may be.

You can quickly accumulate 3dB error in simply not providing the
correct load to the power (dB) determining measurement. Temperature
too can upset readings, but often as not, the simple presence of the
observer disrupts many things. The source is all to often taken for
granted, and all too often has frequency products that add to the
power reading, but are not in the bandwidth of interest. The list
goes on....

73's
Richard Clark, KB7QHC