jim Jarvis wrote:
> not what I meant, Don.
>
> The tower is substantial. Whatever 'proof' was performed was
> minimal, if
> they only charged you $1200:
>
> It really depends on the nature of the AM array. If it were an omni
> situation,
> just taking a couple of readings at a mile would suffice. If,
> however, it was a
> 4 tower inline, where one of the towers had little or negative energy
> in it, the
> pattern could be easily disturbed. In that case, a full proof could
> be required.
> It has to be done when there is no skywave. Depending on Frequency,
> you could
> be limited to 10am to 2pm. It takes a 2 man crew for each car, and
> you might get in
> one radial a day, given 10 points, depending on terrain and roads and
> weather.
> That's 20 man-days. Plus the consulting engineer.
I wonder if this has gotten easier/faster these days with GPS, automated
measurement equipment, better calibration techniques for the probe, and
so forth.
>
> When you take a f.s. reading, you also have to take a picture, time
> stamped.
> This clearly identifies the measurement point, establishes the time
> line, and gives a visual
> record of environmental variables which may be around the point,
> disturbing
> the reading. When the data is reduced, some points need to be
> discarded as
> useless, and replaced with others. More driving, for repeat
> measurements.
I would think that today, measurement validation can be done pretty much
on the fly (i.e. you have a predict of what it should be, and you can do
the distance reduction, etc. automatically)
> Although with computers it's fairly easy, now to reduce all readings,
> each reading
> needs to be reduced to account for distance.
>
> In a re-proof, to verify no change, you could take a skeletal set of
> readings, looking for shifts in nulls. So, you might start by
> taking several readings
> on radials each side of each null. If the f.s. readings haven't
> changed, then
> you could spot-check the main lobe(s), and in the center of each
> null. If they're
> nominally ok, you're good to go. THAT could be achieved in maybe
> two or three days,
> depending on weather and the number of towers. At the current
> contract rate for
> a chief engineer, call it 10-20 hours @ $65... no change found, and
> no consultant required.
> Your $1200 figure is reasonable, under those conditions.
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