[BC] FCC Approves proposed AM MoM Rules

[W2XJ]

The best way to tune an array if you are doing it by FIM is to set ratio 
points. Drive stakes in a perimeter of 1 KM to 1 mile around the array 
every 10 degrees or so. Do an omni proof for those locations and then 
while tuning measure the ratio. Once those look good, run the necessary 
radials.

The big problem, as you point out, is very tight nulls that are affected 
by local re-rad. I don't mean a specific tower or structure but just the 
re-rad off power and phone lines. By the time you get far enough away, 
there is very little signal and that can be subject to interference.

I had one critical Q array where one night pattern radial could only be 
measured around high noon. This is where ratio measurements are very 
useful. I do not believe any array should be designed without the 
ability to operate omni.

As for MOM, while the 'naked' tower measurements serve a purpose to 
determine the pattern, you really need those same measurements with all 
the 'stuff' attached to actually design the system.




Cowboy wrote:

>  Keep in mind that field readings are very often <sic> of questionable
>  reliability anyway. Who is usually carrying the FIM(s) during a full proof ?
>  Can YOU determine the true field reading in the presence of a weak but
>  very close re-radiated signal ?
>  Keep in mind that re-radiators seldom have much ( if any ) affect beyond
>  a few miles out, but where do you take your readings to "prove" the
>  pattern ? They're ALL within just a few miles, aren't they ?
>  What affect does ground conductivity have on sky wave signals ?
>  Why, exactly, do we do a "proof" at all ?
>  ;)
>