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.
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.
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.
n2ea
On Feb 16, 2009, at 7:02 AM, D.Calder wrote:
> Putting up a 350' tower 1/4" mile from a AM station is nothing?
>
> n4zkf
>
>
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