Re: WHOM/WPKQ STL Question

[dan.strassberg@att.net]

Remember that, to a first order, the effective power of 
an FM station increases as the square of HAAT. Until it 
moves to the TV-4 tower (anybody know when that will 
happen?) 'GBH-FM's HAAT will remain 650'. Full Class Cs 
are allowed 100 kW at 2000'. WHOM's coverage is even 
greater--48 kW at 3700', which is roughly equivalent to 
150 kW at 2000'. In other words, from the Great Blue 
Hill site, WGBH-FM would have to increase its power by a 
factor of something like 15 to achieve a coverage radius 
equal to WHOM's. Conversely, if there were a site with 
an HAAT of 3700' in the Boston area and 'GBH-FM used it, 
the station would have to reduce its power to about 3 kW 
to maintain its existing coverage.

Put yet another way, a full Class C FM is, in effect, 
about 30 times as powerful as a full Class B FM. WHOM is 
effectively almost 50 times as powerful as a full Class 
B, and 'GBH-FM is about three times as powerful as a 
full Class B.

Now, if you hold HAAT constant, coverage radii do not 
increase in direct proportion to power. The radius 
increases as some root of the power. I don't know which 
root, but I suspect that it's more like the cube root 
than the square root.
--
dan.strassberg@att.net
617-558-4205
eFax 707-215-6367

> Well, WGBH finally drops out on a car radio on Route 9 somewhere in between
> Cummington and Dalton, which is almost into Pittsfield.  Maybe it's because
> of their dial position, but Amherst is 92 miles west of Boston, and WGBH
> comes in almost like a local here.