[BC] Outside source for checking Modulation Levels

[Cowboy]

On Monday 21 July 2014 03:44:52 pm Jim Turvaville wrote:
> Curious, Cowboy, but are not bandwidth measurements to be taken at the transmitter, not "off-air"?

 73.317 is silent on where the measurement is to be taken, but it can be inferred from
 elsewhere in the rules that bandwidth measurements are to be taken approximately
 1KM from the base of the transmitting antenna. ( arguably )
 This, of course, never yields accurate measurements, but the thought at the
 commission at the time was that the licensee would be able to detect and fix
 spurs generated by their transmission system, not directly a part of
 that transmission system. ( guy wire attachment points, rusty bolts, etc. )

 The informal off the record reasoning was that if the transmission system
 is dirty, one could be dinged one way or the other, and that if it's clean,
 no one would really care where the measurements were made.
 There was a bit of a "reasonable man acting reasonably" thought at the time.
 This, of course, comes from a time before government was over-run
 with lawyers, and before commissioners with no technical understanding
 whatever, paid handsomely by cell phone companies with axes to grind.
 It's always been my practice to do both, document both, make prominent
 and very detailed, the repeatable. ( usually but not always the transmitter
 output terminals )
 In the event of a complaint, I tend to customize the measurement procedure
 and locations to satisfy the complaint.
 A properly calibrated receive antenna at the cell site, for instance.

-- 
Cowboy