effort by at least two FCC commissioners to do something about the
lagging quality of the AM broadcast band is laudable. Since the
subject was broached before the spring 2013 NAB, many ideas on
exactly how to make a meaningful improvement to the AM band have been
FCC is currently circulating a NPRM on the subject, which includes
the following basic ideas:
1. Open a one-time filing window for AM license holders to acquire an FM translator.
2. Relax community coverage rules for AM licensing, allowing greater flexibility for transmitter siting.
3. Eliminate the “Ratchet Rule” used in nighttime allocation studies for new facilities.
4. Permit more widespread use of modulation-dependent carrier level technologies by eliminating STA requirements.
5. Reduce minimum field strength requirements by 25 percent, allowing the use of shorter towers.
proposals may indeed save an AM license holder some money, but none
of them do anything to improve the technical quality of AM
electrically short towers further away from population centers will
reduce signal levels. MDCL will also reduce signal levels somewhat,
depending on how aggressively it is used. Since one of the main
technical flaws with AM broadcasting is the prevalence of electrical
interference, taking steps to further reduce signal strengths over
population areas seems counter-productive.
the three, MDCL is reversible, whereas poor transmitter siting and
short towers are more likely permanent flaws in a station’s
ideas were first put forward in 2009 by the Minority Media
Telecommunication Council as a rescue plan for radio. Reducing costs
for AM broadcasters is generally a good idea, but it is not
synonymous with saving the AM broadcast band.
people have been excoriated for pointing this fact out. Sorry, it is
beyond unhelpful to say nothing. Rather, I would posit that the
industry regulators might want to know exactly what they are doing
before they change the regulations.
simply has to look at the history and the current state of the AM
broadcasting band for an example of what effect technically flawed
regulatory decisions can have.
use of FM translators to simulcast AM stations is not necessarily a
bad idea, especially when it comes to Class C and D stations that
have little or no nighttime coverage. In those situations, the
increased service to the city of license would be a good outcome.
other idea that is being talked about is the conversion of the AM
band to all-digital HD Radio. While some type of digital radio may be
inevitable, there are some serious issues with iBiquity’s HD Radio.
It is proprietary and will remain proprietary in the foreseeable
broadcast station licenses are indeed a trust granted in the public
interest, how can one company, by way of controlling patents, control
all radio broadcasting transmissions within the country?
all-digital transmission is seriously being considered as a way to
improve the AM band, other technologies should be investigated. DRM
(Digital Radio Mondiale) has been in development in Europe since the
early 1990s and is specifically designed to fit into 9 kHz channel
spacing without creating copious sideband interference. Further, DRM
is non-proprietary. Since so much hangs in the balance, would it make
sense to at least test DRM and compare it to the HD Radio test
Thurst is a broadcast engineer with 25 years’ experience working in
the greater New York area. His blog is www.engineeringradio.us.
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