LPFM's in Boston

Scott Fybush scott@fybush.com
Tue Jan 7 16:31:58 EST 2014


On 1/7/2014 3:21 PM, Don wrote:

> Was 94.9 and 102.9 REALLY available?
>
> Did each of these orgnaizations cough up the $5k to $12k to prepare an
> application?
>
> Seems like a big layout for a "maybe" application.
>
> Thoughts?

I can't speak to whether each of those organizations spent that much 
money. It only takes $5-12k if you're hiring a professional consultant 
at the top of the scale. If you have some engineering chops of your own 
and the ability to run some fairly simple studies and read through the 
FCC rules, it's possible to craft an LPFM application for far less.

As for whether 94.9 and 102.9 (and 96.5) are available? Yes, thanks to 
some changes in the FCC's rules, some of them dictated by Congress. It 
is now possible to put an LPFM on a channel third-adjacent to a nearby 
full-power station, thanks to Congressional legislation that eliminated 
third-adjacent spacing restrictions between LPFM and most full-power 
stations. In Boston, however, there are no available third-adjacent 
channels, as you'll see if you step through the dial. The only such 
channels that might have worked would have been 96.3 and 100.1, but they 
had existing class D occupants (W242AA and WBRS, respectively), and the 
spacing to those precluded any co-channel LPFM usage in Boston.

The FCC also decided to accept "D/U ratio" showings of no 
second-adjacent interference. An LPFM applicant can show that if a 
full-power second-adjacent station delivers, let's say, 90 dBu of signal 
at its proposed LPFM site, that there is no point at which the LPFM will 
deliver 130 dBu (90 dBu + the 40 dB ratio between the desired and 
undesired signal) at which there is any population. If it can make that 
showing, it can be granted a waiver of second-adjacent spacing rules.

It happens that 94.9, 102.9 and 96.5 are all channels for which it's at 
least theoretically possible to make such a showing at points within 
greater Boston, which is why there were applicants on those channels.

I analyzed all the greater Boston LPFM apps (and many more from around 
the region) in a special edition of NERW for subscribers back in November:

http://www.fybush.com/nerw-extra-20131126/

s



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