CHAPTER 2

HF SPECTRUM REQUIREMENTS

National Spectrum Requirements

The NTIA Requirements Study addressed 40 radio services and projected U.S. spectrum requirements for a 10-year period based primarily on technical factors. TABLE 2-1 below was taken from the NTIA Requirements Study and depicts the additional U.S. spectrum requirements for both Federal and non-Federal users. NTIA indicated that eight of these radio services needed access to additional spectrum in order to satisfy user requirements to the year 2004. Of those eight radio services, five of them require access to additional HF spectrum. The process of developing national requirements and forwarding them, as necessary, as U.S. requirements to international conferences requires additional consideration of technical, operational and regulatory factors.

HF Spectrum Requirements Summary

NTIA found that access to a total of about 3,088 kHz additional spectrum in the HF band will be needed for radiocommunications for five radio services: broadcasting, amateur, aeronautical mobile, mobile, and maritime mobile. The aggregate U.S. requirement for additional HF broadcasting spectrum was calculated to be approximately 1,900 kHz, since separate requirements were not mutually exclusive between Federal and non-Federal broadcasters. The amateur service requested expansion and upgrading of its allocations for a total of about 900 kHz. The aeronautical mobile service for route (R) and off-route (OR) bands required an additional 108 kHz and 30 kHz, respectively, and an additional 100 kHz in the mobile service to support aeronautical operations. An additional 36-60 kHz was required for maritime mobile service.

A common theme developed in this spectrum availability study was the contention between existing and new technologies—how to find room in the spectrum for new technologies and services while accommodating the existing users of the spectrum. In the United States, and possibly in other nations, congestion continues to increase while policy makers and engineers continue to propose ways to improve spectrum efficiency and accommodate more users. Hence, new systems and services trying to gain access to radio frequencies often must contend with entrenched users with long traditions of serving the public and private needs and who have large investments in equipment.

Note: The radio astronomy community also requested access to an additional 231 MHz, which could be obtained on a local, coordinated basis.

TABLE 2-2

U. S. HF Broadcasting
Service Frequency Allocations

Broadcasting Service

Broadcasters in the United States continue to assert the existence of a long-term shortfall of allocated HF frequencies for international broadcasting operations. Private sector broadcasters indicated their HF spectrum requirement was the shortfall between what they recommended and what was allocated at WARC-92. This was calculated to be approximately 1,655 kHz. The Voice of America identified its unsatisfied spectrum requirements as the shortfall from what it identified in its requirements process to what was finally allocated by WARC-92. These two requirements contain common spectrum and cannot be added directly. Because of overlapping requirements, the total additional spectrum requirements was calculated to be approximately 1,900 kHz. TABLE 2-2 depicts the U.S. broadcasting frequency allocations in the HF band.

Amateur Service

In the NTIA Requirements Study, NTIA indicated that the amateur service requirements in the HF band were for expansion and upgrading of its allocations affecting about 900 kHz. Amateur allocations have been based, in part, on the desirability of having a choice of relatively narrow frequency bands with different propagation properties distributed throughout the spectrum. The amateur service requirements are summarized below:

• In the 3500-4000 kHz band, which is allocated exclusively to the amateur service in the United States but is shared elsewhere, the requirement was for a common, worldwide exclusive 300 kHz allocation within the wider domestic allocation.
• On a shared basis, there was a requirement for about 50 kHz near 5000 kHz for communications during solar cycle minima when maximum usable frequencies are below 7000 kHz.
• To reduce sharing with HF broadcasting in the 7100-7300 kHz band, a 300 kHz band aligned worldwide around or at the 6900-7200 kHz band was requested.
• In the 10100-10350 kHz band, the amateur service requirement is for a new worldwide allocation where the amateur service is primary.
• A new allocation of 50 kHz for primary, exclusive worldwide was needed to extend the 14000-14350 kHz band.
• An additional 150 kHz was requested to expand the present 18068-18168 kHz amateur band.
• An additional 150 kHz was also requested to expand the present 24890-24990 kHz amateur band.
• Finally, a new allocation for the band 29.7-30.0 MHz for amateur-satellite (space-to-Earth).

The 10 U.S. amateur service frequency allocations in the HF band are depicted in TABLE 2-3 below.

Aeronautical Mobile Services

NTIA, in the NTIA Requirements Study, indicated more HF spectrum was required to support air-to-ground communications. In particular, an additional 108 kHz(2) is required for aeronautical mobile (R) service to support international flights on national or international civil air routes and that generally operate beyond the very high frequency (VHF) range of air traffic control stations. The aeronautical mobile (OR) service needed approximately 30 kHz additional HF spectrum to support flight communications between aircraft and aeronautical stations other than those primarily concerned with flight along national or international civil air routes. This generally supports military aviation requirements. Also, an additional 100 kHz requirement was noted for wideband mobile operations in the aeronautical mobile bands from airborne platforms for uses such as imagery, etc. The 100 kHz of additional spectrum is an initial estimate. The aeronautical mobile (OR) and (R) service HF frequency allocations are depicted in TABLE 2-4 below.

Maritime Mobile Service

The U.S. Coast Guard (USCG) indicated a desire for additional HF spectrum for the maritime mobile service. The USCG noted that MOB-87 did not provide adequate spectrum for maritime requirements in the 4 and 8 MHz bands and, consequently, a severe shortfall of spectrum exists below 10 MHz. The NTIA Requirements Study concluded that 36-60 kHz of additional spectrum will be needed to satisfy HF maritime mobile requirements. There are 12 maritime mobile allocations in the HF bands as depicted in TABLE 2-5 below.

Chapter 2 Footnotes:

(1)Markey, infra note 14.

(2)Letter from Gerald J. Markey, Program Director for Spectrum Policy and Management, Federal Aviation Administration, to Joseph P. Camacho, Strategic Spectrum Planning Program, NTIA (Oct. 11, 1996) (on file with NTIA). In response to the review of a draft of this report, the FAA indicated that aeronautical mobile (R) service will need 180 kHz rather than the 108 kHz of additional HF spectrum as previously identified because of unforseen increase in civil flights for which HF data link (HFDL) technology would be used for transoceanic communications requirements. The 180 kHz is needed to fully implement the use of HFDL technology to support 2,500 aircraft simultaneously on a worldwide basis. The purpose of this report is to examine spectrum availability and offer long-range planning options to satisfy spectrum requirements identified in the March 1995 Spectrum Requirements Report. The NTIA Strategic Spectrum Planning Program will be revisiting and revalidating national spectrum requirements as well as other phases of the program and will use this FAA input