[BC] FM TX spacing question (cross-post)

[rstype@aol.com]

In a message dated 2/7/2006 8:21:13 PM Eastern Standard Time, 
steve at stevemichaels.net writes:
Thanks Mark.  What if the overlap is insignificant, and the stations
overlapped agree to mutual interference?  Is that kind of thing still done?

Thanks again,

Steve

Steve:

Section 73.215 (the contour protection rule) is intended to provide 
stations with more flexibility in locating suitable transmitter sites 
and requires that the use of such a site involve the use of 
facilities which provide the required "contour protection" to short 
spaced stations.  In doing so, you must assume that the short spaced 
stations being protected are operating with the maximum facilities 
for their class (even if they aren't), unless the station being 
protected has previously used the contour protection rules to 
similarly protect another station (which effectively forfeits its 
right to be protected to maximum Class facilities).

The provisions of Section 73.215 cannot be used as the basis for an 
upgrade in a station's class.  Any such upgrade must document the 
existence of a fully spaced allotment reference site, even if the 
actual site proposed for the upgrade is short spaced and uses the 
contour protection procedures.

The FCC has never (since the FM Table of Allorments was adopted in 
1964) permitted the use of agreements between stations as the basis 
to create new short spacings or interference.  Until the early 
1990's, however, they did permit the use of such agreements in 
situations involving grandfathered short spacings, but eliminated the 
ability to use such agreements in this situation when they eliminated 
the short spacing "brackets and went to an interference based 
protection standard for grandfathered short spacings.  The only 
remaining situation in which such agreements can be utilized is for 
Class A stations seeking a 6 kilowatt upgrade (either mutual or 
unilateral).  Even then, however, the FCC reserves the right, as they 
always have, to reject such short spacing agreements if it is 
determined that the results would not be in the public interest 
(typically if the new interference created outweighs the new service 
which would result.

Roy Stype
Carl E. Smith Consulting Engineers