[grc] Sky Wave vs Local AM Radio

Tue Oct 27 12:48:43 PDT 2015

More AM improvements ??
http://www.radioworld.com/article/fcc-raises-stakes-will-explore-further-changes-on-am/277392
[1]
Tom

Friday’s AM revitalization order was just the start, apparently. 

The Federal Communications Commission is looking beyond its new order and
raising the possibility of making more and bigger changes to the AM band in
the United States, including some that, if adopted, could challenge
longstanding assumptions and ways of doing business — including the role
of distant nighttime AM signals in American life.

These possibilities arise because in issuing its AM action order Friday,
[2] the FCC also put out a further notice of proposed rulemaking as well as
a notice of inquiry. Both of those are filled with more and bigger ideas
and questions that are likely to keep debate about AM’s future going for
a good while, if possible raising the stakes.

Just one topic — the idea of altering protections for Class A stations
— occupies three pages in the FCC’s further NPRM. There are 57 of these
big stations in the continental United States (plus 16 in Alaska, with
different nighttime protections). The commission now is digging into the
question of whether those signals need the nighttime skywave protection
they've had in the past. It noted that while the big footprint of Class As
have historically been beneficial, the commission has reduced skywave
protection before. “In this proceeding, spectrum scarcity is not the
problem as much as is the need for existing AM stations to overcome an
increasing noise floor that inhibits local service, both day and night.”
Cutting into distant coverage by reducing protections “may well allow
power increases for other stations, enabling them better to serve their
communities and, in the case of some stations, allowing for the first-ever
fulltime AM service to those communities.” 

“Our goal of localism suggests that service from a local news and
information source should be preferred over better reception of a more
distant signal,” it said in something of a money quote on the issue of
distant AMs. “We tentatively conclude, therefore, that (1) all Class A
stations should be protected, both day and night, to their 0.1 mV/m
groundwave contour, from co-channel stations; (2) all Class A stations
should continue to be protected to the 0.5 mV/m groundwave contour, both
day and night, from first adjacent channel stations; and (3) the critical
hours protection of Class A stations should be eliminated completely. We
seek comment on these proposals.”

By contrast, Class A stations in the continental United States are
currently protected in the daytime to their 0.1 mV/m groundwave contour by
co-channel stations, and to their 0.5 mV/m groundwave contour by
adjacent-channel stations. At night, these stations are protected to their
0.5 mV/m - 50 percent skywave contour by co-channel stations, and to their
0.5 mV/m groundwave contour by adjacent-channel stations. And Class As are
protected to their 0.1 mV/m groundwave contour during critical hours. So
while the FCC did not put the question this way explicitly, it appears
asking: Do we even need skywave protection anymore, and if so, what should
it be?

The commission said that based on comments it heard in preparing its AM
actions last week, current Class A protections are “the source of concern
to many AM broadcasters.” It wrote that some people are in favor of
reducing day and nighttime protection for the big signals, and some want to
reduce or eliminate “critical hours” protection for the stations
(critical hours are the two-hour periods after local sunrise and preceding
local sunset). During daytime hours, some 200 Class B and D AMs must reduce
power and/or change to a directional antenna to meet critical hours
protection for the boomers, it wrote. During night hours, other stations
often must invest in complex directional arrays to protect one of the 73
Class As and/or substantially reduce power. 

“Even for those Class B stations that are protected from interference by
other AM stations at night, this often results in sub-standard nighttime
coverage, in order to protect the secondary service area of a larger
station a considerable distance, and often many states away,” the FCC
wrote. Some commenters told the commission they could “provide better
service, with more power to overcome the local noise floor, if the
protections to Class A stations were relaxed.”

The FCC noted the broad service areas of Class As and their benefits to
rural areas and travelers, and also mentioned their role in emergencies,
mentioning the work of WWL after Hurricane Katrina and its aftermath. As
Radio World has reported, iHeartMedia, citing those and other arguments,
has been vocally opposed [3] to such easing of Class A protections; it owns
18 of those 57 Class As in the lower 48, and the commission IHM's position.
But the FCC said it also heard a number of suggestions for eliminating or
reducing protections. 

Thus the commission wants to hear from anyone who would lose service from
Class A stations, and it wants information about areas and populations that
may receive service only from Class As by day or night. “Conversely, we
request specific comment as to the numbers of stations that would be able
to increase power, daytime and nighttime, under our proposal and what
populations would gain service from those power increases.” It also
invited technical comment about the net effect on listeners that could
result from a combination of reduced protection to Class A stations and
power increases by co- and adjacent-channel stations that this proposal
would allow. 

Reading the NPRM, one engineering observer told RW, “It does appear the
commission has decided to lob its own salvo against retaining Class A
skywave protection while preferring to keep the groundwave protection
contours as they are.” He is not certain that this means the entire end
of skywave protections “but it’s clear to me they do want to roll back
the protected limits if not eliminate them altogether. They are inviting
comments and input regarding that proposal and are directly soliciting
evidence that there still are listeners who rely on skywave in remote
areas.” 

And all of the above is merely one section in a list of possible further
FCC actions.

The FCC also tentatively plans to roll back 1991 rule changes regarding
calculation of nighttime RSS values of interfering field strengths and
nighttime interference-free service. It proposes changes to rules providing
daytime protection to AM stations, including a return to pre-1991 0 dB
daytime 1:1 protection ratio for first adjacent channels (“It does not
appear that the post-1991 protection ratio allows for sufficient signal
strength to overcome current levels of environmental noise,” the FCC
staff wrote). It also is thinking about changing second-adjacent channel
groundwave protection, and eliminating third-adjacent channel groundwave
protection. 

It also proposes to revise its rule on siting of FM cross-service fill-in
translators; to modify partial proof of performance rules; and make several
changes to the rules for Method of Moments proofs. And it proposes to
require the surrender of licenses by the 25 remaining dual expanded
band/standard band licensees (it says it has never abandoned its
requirement that those stations relinquish one of their authorizations).

It went even further, opening a Notice of Inquiry raising questions about
the utilization of the AM expanded band. And it even explores the
possibility of changes to the main studio requirements:

“Despite … advances in accessibility to broadcast stations and their
personnel, we are reluctant to eliminate main studio requirements entirely,
because of the … importance of the main studio to the goal of ensuring
station compliance with local service obligations,” the FCC wrote. But it
asks whether it should be more liberal with those waivers, “more open to
requests by commercial stations that can co-locate in studio facilities
used by co-owned stations in a given market?” And if it relaxes the
requirement that each station maintain a separate main studio, is there a
maximum number of co-located stations that it should allow under one roof?
Should any relaxation of staffing requirements be limited to
“standalone” AM stations? Should it require that cell numbers for
station management and staff be posted? Should any relaxation of main
studio or staffing rules be linked to a station’s posting of its public
file to the FCC online database? 

The part of the FCC document that outlines these many possible changes and
questions are on pages 23 to 37 of the PDF [4]. I recommend you dive into
it. 

There is going to be a lot to talk about in coming months. - See more at:
http://www.radioworld.com/article/fcc-raises-stakes-will-explore-further-changes-on-am/277392#sthash.PBnK9SCg.dpuf