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noncom spacing

R

rye

Guest
I posted this over on the non-commercial board, but there is no one there and since this is more technical, engineering is probably more appropriate place.

What is the spacing requirements for-noncommercial stations between channel 201 and 220? I understand that there is not a table of allotment. What are the required distances? Is there any restrictions on 3rd adjacents?
 
In the old days we did it with topo maps and a compass...

Programs like Radio Soft allow you to place a stations contours on a map and move the contours around.

Class A, B, and C stations have the same protection but not mileage protection as in the commercial band.

Using station A which is a class A you place it's 60dbu and 40 dbu contours on a map....an electronic map on a computer.

You create a station profile and make it station B. You create a theoretical contour based on "what if" parameters. 200 watts at 200 feet. Com Study allows you to use the mouse to move this "what if" station around station A until you find the sweet spot where the 40dbu contours of both stations do not overlap each station's protected 60dbu contours.

Then you tweek it by checking a population count at each what if location. highest pop, lowest interference, available towers, etc.

A new station by Radio Soft and the FCC database. Now wait for a window and file an application.

> I posted this over on the non-commercial board, but there is
> no one there and since this is more technical, engineering
> is probably more appropriate place.
>
> What is the spacing requirements for-noncommercial stations
> between channel 201 and 220? I understand that there is not
> a table of allotment. What are the required distances? Is
> there any restrictions on 3rd adjacents?
>
 
It is by contour, not by minimum distances. Except for stations adjacent to commercial channels.

See Section 73.509 of the rules.

This is why you will find many non-com stations much closer to each other than you would expect to find in the commercial band.

Note that stations may be listed as "Class A, Class B, or Class C" (and the various permutations such as C-3, etc.). This is done to comply with treaties with Canada and Mexico.

To increase power or change transmitter site on a non-com you must then calculate the contours of the station as proposed and whether or not it will exceed the protections provided by 73.509.
 
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