# SECTION 4 CHARACTERIZATION OF FEDERAL GOVERNMENT RADIO SYSTEMS AND SPECTRUM USAGE

**4.1 INTRODUCTION**

The 1.7-80 MHz frequency range encompasses the high end of the medium
frequency band (MF, 1.7-3.0 MHz), the high frequency band (HF, 3-30
MHz), and the low end of the very high frequency band (VHF, 30-80 MHz)
portion of the spectrum. At HF frequencies and below, communications can
be made possible over a very long distance (*i.e.*, thousands of miles)
using skywave, ionospheric propagation. A significant feature of
communications using the HF bands is the great variability in radio
propagation and ambient radio noise levels. These variations as a
function of time of day, season, year, and geographic location have been
extensively studied and are well understood. Modern technology,
especially automatic link establishment (ALE), has reestablished HF as
an important, reliable mode of communications. At VHF frequencies,
communications are more local, generally limited to tens of miles.

The 1.7-80 MHz band supports a variety of radio services that are
adapted to the propagation characteristics inherent in this range. In
all, thirteen radio services are supported in the 1.7-80 MHz band (Table
4-1). Most of these radio services are used by federal agencies and are
instrumental to the Federal Government in meeting its various
radiocommunications requirements and responsibilities.

**Table 4-1: Radio Services in the 1.7-80 MHz Bands**

  -----------------------------------------------------------------------
  Fixed

  Mobile

  Land Mobile

  Maritime Mobile

  Aeronautical Mobile (R)

  Aeronautical Mobile (OR)

  Radiolocation

  Amateur

  Amateur-satellite

  Radio Astronomy

  Broadcasting

  Aeronautical Radionavigation

  Standard Frequency and Time signal
  -----------------------------------------------------------------------

**4.2 ALLOCATIONS OVERVIEW**

In the United States, the 1.7-80 MHz range is made up of 157 frequency
bands. In accordance with the National Table of Frequency Allocations,
each of these bands is designated for either exclusive federal use,
exclusive non-federal use, or shared. The spectrum allocations in this
band include many cases of band-sharing between the federal and
non-federal users, and between different radio services. A total of 110
bands are shared by federal and non-federal users. Only 12 bands are
allocated exclusively to the Federal Government for fixed and mobile
services (Table 4-2). In comparison, 34 bands are allocated for
non-federal use on an exclusive basis for various radio services
including: amateur, amateur-satellite, fixed, land mobile, and
broadcasting (Table 4-3). Over 50 footnotes to the allocation tables are
associated with these bands, providing for additional spectrum sharing
or constraints on operations.

**Table 4-2: Frequency Bands Allocated Exclusively to the Federal
Government**

  ----------------------- ----------------------- -----------------------
  25330-25550 kHz         30-30.56 MHz            38.25-39 MHz

  26480-26950 kHz         32-33 MHz               40-42 MHz

  27540-28000 kHz         34-35 MHz               46.6-47 MHz

  29.89-29.91 MHz         36-37 MHz               49.6-50 MHz
  ----------------------- ----------------------- -----------------------

**Table 4-3: Frequency Bands Allocated Exclusively to Non-Federal
Use**[^1]

  ----------------------------------- -----------------------------------
  1800-1900 kHz                       28--29.89 MHz

  3500-4000 kHz                       29.91-30 MHz

  7000-7300 kHz                       30.56-32 MHz

  10100-10150 kHz                     33-34 MHz

  14000-14350 kHz                     35-36 MHz

  18068-18168 kHz                     37-37.5 MHz

  21000-21450 kHz                     39-40 MHz

  24890-24990 kHz                     42-46.6 MHz

  25005-25010 kHz                     47-49.6 MHz

  25210-25330 kHz                     50-73 MHz

  26175-26480 kHz                     75.4-88 MHz

  26950-27540 kHz                     
  ----------------------------------- -----------------------------------

The allocations to radio services in the 1.7-80 MHz band can be broadly
grouped into four overall categories as shown in Table 4-4.

**Table 4-4: Frequency Allocations in the 1.7 -- 80 MHz Band by Service
Category**[^2]

+------------------------------+--------------+------------------------+
| **Service Category**         | *            | **Percent of Total**   |
|                              | *Bandwidth** |                        |
|                              |              | **1.7 -- 80 MHz Band** |
+------------------------------+--------------+------------------------+
| Fixed & Mobile               | 40.9 MHz     | 52%                    |
| Communications               |              |                        |
+------------------------------+--------------+------------------------+
| Broadcasting (including      | 25.7 MHz     | 33%                    |
| shortwave & TV)              |              |                        |
+------------------------------+--------------+------------------------+
| Amateur/Amateur-Satellite    | 10.4 MHz     | 13%                    |
+------------------------------+--------------+------------------------+
| Other                        | 3.1 MHz      | 4%                     |
+------------------------------+--------------+------------------------+

The largest category, fixed and mobile communications, includes a number
of specific allocations for various land, air and sea communications
services. For purposes of this summary, the "Other" category is
comprised of the aeronautical radionavigation, radio astronomy,
radiolocation, and standard frequency and time signal. Table 4-5 shows
the breakdown of the total number of bands allocated to all the radio
services, including their respective total bandwidths. This Phase 1
study focused largely on fixed and mobile communications systems. The
NTIA Phase 2 effort will further explore other services.

Further discussion on these radio services and spectrum use are
presented in Appendix C.

**Table 4-5**: Summary of Bands Allocated to the Radio Services (1.7-80
MHz Band)

+----------------+----------+-------------+-------------+-------------+
| **Radio        | **No. of | **Total     | **No. of    | **Total     |
| Service**      | Bands    | Bandwidth** | Bands**     | Bandwidth** |
|                | (Fed.    |             |             |             |
|                | Gov't)** | **(kHz)**   | **(Non      | **(kHz)**   |
|                |          |             | -Federal)** |             |
+----------------+----------+-------------+-------------+-------------+
| Aeronautical   | 11       | 1331        | 11          | 1331        |
| Mobile (R)     |          |             |             |             |
+----------------+----------+-------------+-------------+-------------+
| Aeronautical   | 10       | 845         | 10          | 845         |
| Mobile (OR)    |          |             |             |             |
+----------------+----------+-------------+-------------+-------------+
| Aeronautical   | 1        | 400         | 1           | 400         |
| R              |          |             |             |             |
| adionavigation |          |             |             |             |
+----------------+----------+-------------+-------------+-------------+
| Amateur        | \--      | \--         | 12          | 7650        |
+----------------+----------+-------------+-------------+-------------+
| Ama            | \--      | \--         | 6           | 2700        |
| teur-Satellite |          |             |             |             |
+----------------+----------+-------------+-------------+-------------+
| Broadcasting   | 18       | 3720        | 20          | 25720       |
+----------------+----------+-------------+-------------+-------------+
| Fixed          | 58       | 19810       | 55          | 18235       |
+----------------+----------+-------------+-------------+-------------+
| Land Mobile    | \--      | \--         | 17          | 14064       |
+----------------+----------+-------------+-------------+-------------+
| Maritime       | 15       | 4857        | 15          | 4857        |
| Mobile         |          |             |             |             |
+----------------+----------+-------------+-------------+-------------+
| Mobile         | 42       | 17560       | 19          | 5531        |
+----------------+----------+-------------+-------------+-------------+
| Radiolocation  | 3        | 365         | 3           | 365         |
+----------------+----------+-------------+-------------+-------------+
| Radio          | 4        | 2270        | 4           | 2270        |
| Astronomy      |          |             |             |             |
+----------------+----------+-------------+-------------+-------------+
| Standard       | 13       | 90          | 13          | 90          |
| Frequency &    |          |             |             |             |
| Time Signal    |          |             |             |             |
+----------------+----------+-------------+-------------+-------------+

**4.3 OVERVIEW OF FEDERAL GOVERNMENT SPECTRUM USE**

The Federal Government agencies use the 1.7-80 MHz band, specifically
the HF band, extensively for emergency services, including
communications support for the Department of Defense (DoD); Coast Guard
operations for distress, digital selective calling, search and rescue,
and other safety of life operations; Department of Interior (DOI) and
Department of Agriculture (DOA) for the management, maintenance, and
preservation of our natural resources; Department of Justice (DOJ) and
Department of Homeland Security (DHS) for law enforcement activities,
and backup or emergency uses of the other federal agencies. Backup
systems play a crucial role in times of national security emergency
preparedness (NSEP) emergencies, when regular communications links are
disrupted, inadequate or non-operational. In an emergency situation, the
Federal Government has a program for the use of government HF
frequencies for the shared

resources (SHARES) network. The SHARES network intends to provide backup
capability to exchange critical information among federal entities by HF
radio in crisis situations.

Federal agencies, especially the DoD and law enforcement community,
utilizing this portion of the radio spectrum employ over the horizon and
encrypted radios that may utilize ALE which samples channels
periodically to determine channel availability. All these systems could
be a part of the emergency communications network. As indicated earlier,
the 1.7-80 MHz band, for the most part, is shared by the federal and
non-federal users and is extensively used by both communities for
numerous radio applications.

There are more than 59,000 Federal Government frequency assignments
authorized in the 1.7-80 MHz band.[^3] Table 4-6 shows the number of
frequency assignments by radio service and by entity. These assignments
support the numerous federal activities and requirements in the 1.7-80
MHz band (*see* Appendix C).

**Table 4-6: Federal and Non-Federal Frequency Assignments by Radio
Service in the 1.7-80 MHz band**

<table>
<colgroup>
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 7%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 9%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td><strong>Entity</strong></td>
<td><p><strong>Aero.</strong></p>
<p><strong>Mobile</strong></p></td>
<td><p><strong>Radio-</strong></p>
<p><strong>nav.</strong></p></td>
<td><strong>BC</strong></td>
<td><strong>Fixed</strong></td>
<td><p><strong>Land</strong></p>
<p><strong>Mobile</strong></p></td>
<td><p><strong>Mar.</strong></p>
<p><strong>Mobile</strong></p></td>
<td><strong>Mobile</strong></td>
<td><strong>Radio -location</strong></td>
<td><strong>SF &amp; TS</strong></td>
<td><strong>Others</strong></td>
<td><strong>Total by Entity</strong></td>
</tr>
<tr class="even">
<td>A</td>
<td>76</td>
<td></td>
<td>1</td>
<td>753</td>
<td>188</td>
<td></td>
<td>175</td>
<td></td>
<td></td>
<td></td>
<td>1193</td>
</tr>
<tr class="odd">
<td>AF</td>
<td>2491</td>
<td>18</td>
<td></td>
<td>1112</td>
<td>844</td>
<td>323</td>
<td>217</td>
<td>23</td>
<td></td>
<td>103</td>
<td>5131</td>
</tr>
<tr class="even">
<td>AR</td>
<td>192</td>
<td>142</td>
<td>1</td>
<td>5521</td>
<td>2350</td>
<td>433</td>
<td>1844</td>
<td>20</td>
<td></td>
<td>30</td>
<td>10533</td>
</tr>
<tr class="odd">
<td>BBG</td>
<td></td>
<td></td>
<td>469</td>
<td>146</td>
<td>3</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td>618</td>
</tr>
<tr class="even">
<td>C</td>
<td>130</td>
<td></td>
<td></td>
<td>644</td>
<td>625</td>
<td>512</td>
<td>31</td>
<td>1</td>
<td>12</td>
<td>32</td>
<td>1987</td>
</tr>
<tr class="odd">
<td>CG</td>
<td>888</td>
<td>3</td>
<td></td>
<td>554</td>
<td>9</td>
<td>7034</td>
<td>15</td>
<td></td>
<td></td>
<td></td>
<td>8503</td>
</tr>
<tr class="even">
<td>DHS</td>
<td>40</td>
<td></td>
<td></td>
<td>1118</td>
<td>33</td>
<td></td>
<td>72</td>
<td></td>
<td></td>
<td></td>
<td>1263</td>
</tr>
<tr class="odd">
<td>E</td>
<td>232</td>
<td></td>
<td></td>
<td>252</td>
<td>301</td>
<td>17</td>
<td>86</td>
<td>2</td>
<td></td>
<td>4</td>
<td>894</td>
</tr>
<tr class="even">
<td>EPA</td>
<td></td>
<td></td>
<td></td>
<td>90</td>
<td>30</td>
<td>10</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td>130</td>
</tr>
<tr class="odd">
<td>FAA</td>
<td>293</td>
<td>1564</td>
<td></td>
<td>1506</td>
<td>129</td>
<td></td>
<td>24</td>
<td></td>
<td></td>
<td>1</td>
<td>3517</td>
</tr>
<tr class="even">
<td>FCC</td>
<td></td>
<td></td>
<td></td>
<td>459</td>
<td>484</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td>943</td>
</tr>
<tr class="odd">
<td>HHS</td>
<td></td>
<td></td>
<td></td>
<td>571</td>
<td>32</td>
<td></td>
<td>25</td>
<td></td>
<td></td>
<td></td>
<td>628</td>
</tr>
<tr class="even">
<td>I</td>
<td>124</td>
<td></td>
<td>3</td>
<td>317</td>
<td>421</td>
<td>145</td>
<td>330</td>
<td></td>
<td></td>
<td></td>
<td>1340</td>
</tr>
<tr class="odd">
<td>J</td>
<td>2</td>
<td></td>
<td></td>
<td>1890</td>
<td>295</td>
<td>16</td>
<td>167</td>
<td></td>
<td></td>
<td></td>
<td>2370</td>
</tr>
<tr class="even">
<td>N</td>
<td>2433</td>
<td></td>
<td></td>
<td>2950</td>
<td>2525</td>
<td>5346</td>
<td>2663</td>
<td>26</td>
<td></td>
<td>56</td>
<td>15999</td>
</tr>
<tr class="odd">
<td>NASA</td>
<td>16</td>
<td></td>
<td></td>
<td>72</td>
<td>41</td>
<td>62</td>
<td>26</td>
<td></td>
<td></td>
<td>6</td>
<td>223</td>
</tr>
<tr class="even">
<td>NG</td>
<td>399</td>
<td>119</td>
<td></td>
<td>1158</td>
<td>1191</td>
<td>1252</td>
<td>646</td>
<td>144</td>
<td></td>
<td>1135</td>
<td>6044</td>
</tr>
<tr class="odd">
<td>S</td>
<td></td>
<td></td>
<td></td>
<td>118</td>
<td>3</td>
<td></td>
<td>10</td>
<td></td>
<td></td>
<td></td>
<td>131</td>
</tr>
<tr class="even">
<td>SI</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td>1</td>
<td>7</td>
<td>106</td>
<td></td>
<td></td>
<td></td>
<td>114</td>
</tr>
<tr class="odd">
<td>T</td>
<td>149</td>
<td></td>
<td></td>
<td>56</td>
<td>199</td>
<td>8</td>
<td>708</td>
<td></td>
<td></td>
<td></td>
<td>1120</td>
</tr>
<tr class="even">
<td>TRAN</td>
<td></td>
<td></td>
<td></td>
<td>137</td>
<td>9</td>
<td>6</td>
<td>3</td>
<td></td>
<td></td>
<td></td>
<td>155</td>
</tr>
<tr class="odd">
<td>TVA</td>
<td></td>
<td></td>
<td></td>
<td>22</td>
<td>82</td>
<td>2</td>
<td>144</td>
<td>2</td>
<td></td>
<td></td>
<td>252</td>
</tr>
<tr class="even">
<td>VA</td>
<td></td>
<td></td>
<td></td>
<td>107</td>
<td>52</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td>159</td>
</tr>
<tr class="odd">
<td>Others</td>
<td>5</td>
<td></td>
<td>8</td>
<td>1366</td>
<td>145</td>
<td>106</td>
<td>383</td>
<td></td>
<td></td>
<td>17</td>
<td>2030</td>
</tr>
<tr class="even">
<td colspan="11"><strong>Total Assignments</strong></td>
<td><strong>65,277</strong></td>
</tr>
<tr class="odd">
<td colspan="12"><p><strong>Legend:</strong> Aero = Aeronautical, Nav =
Navigation, BC = Broadcasting, SF&amp;TS = Standard Frequency and Time
Signal,</p>
<p>Mar = Maritime, A =Agriculture, AF = Air Force, AR = Army, BBG =
Broadcasting Board of Governors, C = Commerce,</p>
<p>CG = Coast Guard, DHS = Homeland Security, E = Energy, EPA =
Environmental Protection Agency, FAA = Federal Aviation Administration,
FCC = Federal Communications Commission, I = Interior, J = Justice, L=
Labor, N = Navy,</p>
<p>NASA = National Aeronautics and Space Administration, NG =
Non-Government, NS = National Security Agency,</p>
<p>NSF = National Science Foundation, S = State, SI = Smithsonian
Institution, T = Treasury, TRAN = Transportation,</p>
<p>TVA = Tennessee Valley Authority, VA = Veterans
Administration</p></td>
</tr>
</tbody>
</table>

**4.4 SUMMARY OF REPRESENTATIVE FEDERAL GOVERNMENT SYSTEMS IN THE 1.7-80
MHz BAND**

Federal agencies employ a number of radiocommunication systems that have
a significant presence in the 1.7 -- 80 MHz band. These systems,
summarized in Table 4-7, are presented as the representative systems for
certain radio services because they are prevalent (*e.g.*, the number of
frequency assignments supporting these systems overwhelm the others) and
their uses are widespread in the band. The functions and operations of
these systems are described in Appendix C, as appropriate.

**Table 4-7: Summary of Representative Federal Government** Radio
Systems in the 1.7-80 MHz Band

  ----------------- ----------- ------------------- ------------------------------
  **Radio Service** **Freq.     **Federal Entity**  **Representative System**
                    Band                            
                    (MHz)**                         

  Fixed             2-30        Many federal        HF Shared Resources (SHARES)
                                agencies            

                                DHS/FEMA            FEMA National Radio System
                                                    (FNRC)

                                Army/Corps of       HF Emergency Operations Net
                                Engineers           

                                FAA                 National Radio Communications
                                                    System (NRCS)

  Fixed             30-50       Many federal        Base Stations (Repeaters)
                                agencies            

  Land Mobile       2-30        DHS/US Customs      Custom's Over the Horizon
                                                    Enforcement Network (COTHEN)

  Land Mobile       30-50       DoD                 Single-Channel Ground and
                                                    Airborne Radio System
                                                    (SINCGARS)

  Maritime Mobile   2-30        DHS/USCG            Global Maritime Distress and
                                                    Safety System (GMDSS)

  Aeronautical      2-30        FAA                 Air Traffic Control (VOLMET)
  Mobile (R)                                        

  Aeronautical      2-30        DoD                 Tactical Radios (AN/ARC
  Mobile (OR)                                       Series)

  Radionavigation   74.8-75.2   FAA                 Marker Beacons

  Radiolocation     2-3.4       DoD                 Over the Horizon Radars (OTHR)

  Broadcasting      2-30        BBG                 Voice of America (VOA)

  Standard Freq. &  2-30        DOC/NIST            WWV & WWVH Stations
  Time Signal                                       
  ----------------- ----------- ------------------- ------------------------------

**4.5 REPRESENTATIVE TECHNICAL CHARACTERISTICS OF FEDERAL EQUIPMENT**

The technical characteristics of equipment in the 1.7-80 MHz band can be
largely grouped into uses below and above 30 MHz, with considerable
consistency within these two frequency bands. Table 4-8 summarizes
representative technical characteristics of federal radio equipment in
the 1.7-80 MHz band. Appendix C provides a more in-depth presentation of
these technical characteristics.

**Table 4-8: Representative Technical Characteristics of Receivers in
the 1.7-80 MHz Band**

+---------+--------+----------+----+-------+--------+------+----------+
| **Radio | **S    | **Freq.  | ** | **An  | **A    | *    | **Mo     |
| Se      | tation | Band**   | BW | tenna | ntenna | *Ant | dulation |
| rvice** | Type** |          | ** | Gain  | Height | enna | Type**   |
|         |        | *        |    | (d    | (ft)** | Ty   |          |
|         |        | *(MHz)** | *  | Bi)** |        | pe/P |          |
|         |        |          | *( |       |        | ol** |          |
|         |        |          | kH |       |        |      |          |
|         |        |          | z) |       |        |      |          |
|         |        |          | ** |       |        |      |          |
+---------+--------+----------+----+-------+--------+------+----------+
| Fixed   | Fixed  | 2-30     | 2  | 0-2   | 30-140 | Di   | J3E,     |
|         |        |          | .8 |       |        | pole | simplex  |
|         |        |          |    |       |        | /V&H | o        |
|         |        |          |    |       |        |      | peration |
+---------+--------+----------+----+-------+--------+------+----------+
| Fixed   | Fixed  | 30-50    | 16 | 0-3   | 10-400 | Wh   | F3E,     |
|         |        |          |    |       |        | ip/V | simplex  |
|         |        |          |    |       |        |      | and half |
|         |        |          |    |       |        |      | duplex   |
+---------+--------+----------+----+-------+--------+------+----------+
| Land    | Base   | 2-30     | 2  | 0     | 30-100 | Whip | J3E,     |
| Mobile  |        |          | .8 |       |        | /V&H | simplex  |
|         |        |          |    |       |        |      | o        |
|         |        |          |    |       |        |      | peration |
+---------+--------+----------+----+-------+--------+------+----------+
| Land    | Land   | 2-30     | 2  | 0-2   | 6-32   | Whip | J3E,     |
| Mobile  | Mobile |          | .8 |       |        | /V&H | simplex  |
|         |        |          | -3 |       |        |      | o        |
|         |        |          |    |       |        |      | peration |
+---------+--------+----------+----+-------+--------+------+----------+
| Land    | Base   | 29.7-50  | 16 | 3     | 30-400 | Wh   | J3E,     |
| Mobile  |        |          |    |       |        | ip/V | simplex  |
|         |        |          |    |       |        |      | and half |
|         |        |          |    |       |        |      | duplex   |
+---------+--------+----------+----+-------+--------+------+----------+
| Land    | Land   | 29.7-50  | 16 | 0     | 6-32   | Wh   | J3E,     |
| Mobile  | Mobile |          |    |       |        | ip/V | simplex  |
|         |        |          |    |       |        |      | and half |
|         |        |          |    |       |        |      | duplex   |
+---------+--------+----------+----+-------+--------+------+----------+
| Aeron   | Aerona | 2-30     | 2  | 0     | u      | V    | J3E,     |
| autical | utical |          | .8 |       | nknown | ario | simplex  |
| Mobile  | (G     |          |    |       |        | us/V | o        |
| (       | round) |          |    |       |        |      | peration |
| AM(R)S) |        |          |    |       |        |      |          |
+---------+--------+----------+----+-------+--------+------+----------+
| Aeron   | Ai     | 2-30     | 2  | 0     | 18000  | Con  | J3E,     |
| autical | rcraft |          | .8 |       | -40000 | form | simplex  |
| Mobile  |        |          |    |       |        | al/V | o        |
| (       |        |          |    |       |        |      | peration |
| AM(R)S) |        |          |    |       |        |      |          |
+---------+--------+----------+----+-------+--------+------+----------+
| Aeron   | Fixed\ | 2-30     | 6  | 0     | u      | Wh   | J3E,     |
| autical | (G     |          |    |       | nknown | ip/V | simplex  |
| Fixed   | round) |          |    |       |        |      | o        |
| (NRCS)  |        |          |    |       |        |      | peration |
+---------+--------+----------+----+-------+--------+------+----------+
| Aeron   | Ai     | 30-50    | 16 | 0     | 18000  | Bla  | J3E,     |
| autical | rcraft |          |    |       | -40000 | de/V | simplex  |
| Mobile  |        |          |    |       |        |      | o        |
|         |        |          |    |       |        |      | peration |
+---------+--------+----------+----+-------+--------+------+----------+
| M       | Ship & | 2-30     | 2  | 0-2   | u      | Wh   | J3E,     |
| aritime | Coast  |          | .8 |       | nknown | ip/V | simplex  |
| Mobile  |        |          |    |       |        |      | o        |
|         |        |          |    |       |        |      | peration |
+---------+--------+----------+----+-------+--------+------+----------+
| M       | Ship & | 30-50    | 16 | 2     | 30-100 | Wh   | J3E,     |
| aritime | Coast  |          |    |       |        | ip/V | simplex  |
| Mobile  |        |          |    |       |        |      | o        |
|         |        |          |    |       |        |      | peration |
+---------+--------+----------+----+-------+--------+------+----------+
| Aeron   | Ai     | 7        | 0  | -     | 0-3000 | Bla  | A2A      |
| autical | rcraft | 4.8-75.2 | .8 | 2.5 - |        | de/H |          |
| R       |        |          | -6 | 2     |        |      |          |
| adionav |        |          |    |       |        |      |          |
| igation |        |          |    |       |        |      |          |
|         |        |          |    |       |        |      |          |
| S       |        |          |    |       |        |      |          |
| ervices |        |          |    |       |        |      |          |
| (ARNS)  |        |          |    |       |        |      |          |
+---------+--------+----------+----+-------+--------+------+----------+
| S       | I      | 2-30     |    | 0     | 6-30   | Wh   | A2       |
| tandard | n-home |          |    |       |        | ip/V |          |
| Freq. & |        |          |    |       |        |      |          |
| Time    |        |          |    |       |        |      |          |
| Signal  |        |          |    |       |        |      |          |
+---------+--------+----------+----+-------+--------+------+----------+
| Radio   | Fixed  | 13.      |    | 23    | 100    | P    | Receive  |
| As      |        | 36-13.41 |    |       |        | arab | Only     |
| tronomy |        |          |    |       |        | olic |          |
|         |        | 37.5-38, |    |       |        |      |          |
|         |        | 73-74.6  |    |       |        |      |          |
+---------+--------+----------+----+-------+--------+------+----------+
| **      |        |          |    |       |        |      |          |
| Legend: |        |          |    |       |        |      |          |
| Freq**. |        |          |    |       |        |      |          |
| =       |        |          |    |       |        |      |          |
| Fre     |        |          |    |       |        |      |          |
| quency, |        |          |    |       |        |      |          |
| *       |        |          |    |       |        |      |          |
| *Pol.** |        |          |    |       |        |      |          |
| =       |        |          |    |       |        |      |          |
| Polari  |        |          |    |       |        |      |          |
| zation, |        |          |    |       |        |      |          |
| **V** = |        |          |    |       |        |      |          |
| Ve      |        |          |    |       |        |      |          |
| rtical, |        |          |    |       |        |      |          |
| **H** = |        |          |    |       |        |      |          |
| Hor     |        |          |    |       |        |      |          |
| izontal |        |          |    |       |        |      |          |
|         |        |          |    |       |        |      |          |
| **J3E** |        |          |    |       |        |      |          |
| =       |        |          |    |       |        |      |          |
| Single  |        |          |    |       |        |      |          |
| s       |        |          |    |       |        |      |          |
| ideband |        |          |    |       |        |      |          |
| with    |        |          |    |       |        |      |          |
| sup     |        |          |    |       |        |      |          |
| pressed |        |          |    |       |        |      |          |
| c       |        |          |    |       |        |      |          |
| arrier, |        |          |    |       |        |      |          |
| using a |        |          |    |       |        |      |          |
| single  |        |          |    |       |        |      |          |
| channel |        |          |    |       |        |      |          |
| con     |        |          |    |       |        |      |          |
| taining |        |          |    |       |        |      |          |
| an      |        |          |    |       |        |      |          |
| analog  |        |          |    |       |        |      |          |
| signal  |        |          |    |       |        |      |          |
| for     |        |          |    |       |        |      |          |
| te      |        |          |    |       |        |      |          |
| lephony |        |          |    |       |        |      |          |
|         |        |          |    |       |        |      |          |
| **F3E** |        |          |    |       |        |      |          |
| =       |        |          |    |       |        |      |          |
| Fr      |        |          |    |       |        |      |          |
| equency |        |          |    |       |        |      |          |
| mod     |        |          |    |       |        |      |          |
| ulated, |        |          |    |       |        |      |          |
| using a |        |          |    |       |        |      |          |
| single  |        |          |    |       |        |      |          |
| channel |        |          |    |       |        |      |          |
| con     |        |          |    |       |        |      |          |
| taining |        |          |    |       |        |      |          |
| an      |        |          |    |       |        |      |          |
| analog  |        |          |    |       |        |      |          |
| signal  |        |          |    |       |        |      |          |
| for     |        |          |    |       |        |      |          |
| te      |        |          |    |       |        |      |          |
| lephony |        |          |    |       |        |      |          |
|         |        |          |    |       |        |      |          |
| **N0N   |        |          |    |       |        |      |          |
| or      |        |          |    |       |        |      |          |
| P0N** = |        |          |    |       |        |      |          |
| No      |        |          |    |       |        |      |          |
| mod     |        |          |    |       |        |      |          |
| ulating |        |          |    |       |        |      |          |
| signal  |        |          |    |       |        |      |          |
| and no  |        |          |    |       |        |      |          |
| info    |        |          |    |       |        |      |          |
| rmation |        |          |    |       |        |      |          |
| tran    |        |          |    |       |        |      |          |
| smitted |        |          |    |       |        |      |          |
|         |        |          |    |       |        |      |          |
| **A2A** |        |          |    |       |        |      |          |
| =       |        |          |    |       |        |      |          |
| Double  |        |          |    |       |        |      |          |
| s       |        |          |    |       |        |      |          |
| ideband |        |          |    |       |        |      |          |
| using a |        |          |    |       |        |      |          |
| single  |        |          |    |       |        |      |          |
| channel |        |          |    |       |        |      |          |
| con     |        |          |    |       |        |      |          |
| taining |        |          |    |       |        |      |          |
| a       |        |          |    |       |        |      |          |
| qu      |        |          |    |       |        |      |          |
| antized |        |          |    |       |        |      |          |
| or      |        |          |    |       |        |      |          |
| digital |        |          |    |       |        |      |          |
| signal  |        |          |    |       |        |      |          |
| with    |        |          |    |       |        |      |          |
| mod     |        |          |    |       |        |      |          |
| ulating |        |          |    |       |        |      |          |
| sub     |        |          |    |       |        |      |          |
| carrier |        |          |    |       |        |      |          |
+---------+--------+----------+----+-------+--------+------+----------+

**4.6** **SENSITIVE OR PROTECTED FREQUENCIES IN THE 1.7-80 MHz\
BAND**

All spectrum regulatory organizations, including the FCC, NTIA, and the
ITU, have long recognized that certain frequencies or bands in the radio
spectrum, including the 1.7-80 MHz range, require special protection
because of the critical or sensitive functions they support. Some of
these functions include: distress and safety, standard frequency and
time signal, radio astronomy, and radionavigation.

Three parts of the FCC Rules and Regulations, Parts 15, 80 and 87,
provide specific lists of protected frequencies in this range. While all
three impose limitations on licensed services or unlicensed intentional
radiation devices in these bands, the concept may be relevant as well to
the unintentional radiation from BPL systems because of the interference
risks. The ITU Radio Regulations, Appendices 13 and 15, provide similar
lists of protected frequencies. Table 4-9 summarizes and compares these
lists of protected frequencies adopted by the FCC and ITU, showing the
various functions being protected.

Based on these FCC and ITU sources, NTIA proposes a candidate list of 41
protected frequencies for BPL systems. This candidate list, shown in
Table 4-9, comprises a total of less than 6% of the spectrum in the
1.7-30 MHz range and about 5.5% of the spectrum in the 30-80 MHz range.
Operations supported by these frequencies are vital to certain federal
communications requirements such as safety of life and property,
disaster communications, reception of weak galactic signals by the radio
astronomy community, and safety of flight. In some cases, these
frequencies or frequency bands provide for essential communications
incident to or in connection with disasters or other incidents that
involve loss of communication facilities normally available or that
require the temporary establishment of communication facilities beyond
those normally available.

The applicability of these candidate sensitive frequencies or others
with respect to BPL systems will be examined further in the NTIA Phase 2
effort.

**Table 4-9: Lists of Protected Frequencies Recognized by the FCC and
ITU in the 1.7-80 MHz Band**

+----------+-------+-------+-------+-------+---------+----------------+
| **FCC**  | **    | **IT  | **IT  | **I   | **FUN   | **CANDIDATE    |
|          | FCC** | U-R** | U-R** | TU-R\ | CTION** | LIST OF        |
| **       |       |       |       | App   |         | PROTECTED      |
| 15.205** | **87. | **Ap  | **App | 27\   |         | FREQUENCIES    |
|          | 149** | p15** | 13**  | AM(R) |         | FOR BPL**      |
|          |       |       |       | S**   |         |                |
|          | **80. | **(GM | **(No |       |         |                |
|          | 229** | DSS)* | n-GMD |       |         |                |
|          |       | *[^4] | SS)** |       |         |                |
+==========+=======+=======+=======+=======+=========+================+
|          | 2091  |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 2173.    | 21    | 2     | 2     |       | N       | 2173.5-2190.5  |
| 5-2190.5 | 74.5, | 174.5 | 174.5 |       | BDP-COM |                |
|          |       |       |       |       |         |                |
|          | 2182, | 2182  | 2182  |       | RTP-COM |                |
|          |       |       |       |       |         |                |
|          | 2     | 2     | 2     |       | DSC     |                |
|          | 187.5 | 187.5 | 187.5 |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 2500  |       |       |       | SF&TS   | 2495-2505      |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 2850  | ATC     | 2850-3025      |
|          |       |       |       | -3025 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 3023  | 3023  | 3023  |       | A       | 3023-3026      |
|          |       |       |       |       | ERO-SAR |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 3400  | ATC     | 3400-3500      |
|          |       |       |       | -3500 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 4000  |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 4        | 4125  | 4125  | 4125  |       | RTP-COM | 4125-4128      |
| 125-4128 | -4128 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 4177.25  | 4     | 4     | 4     |       | N       | 4              |
| -4177.75 | 177.5 | 177.5 | 177.5 |       | BDP-COM | 177.25-4177.75 |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 4188  |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 4207.25  | 4     | 4     | 4     |       | DSC     | 4              |
| -4207.75 | 207.5 | 207.5 | 207.5 |       |         | 207.25-4207.75 |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 4650  | ATC     | 4650-4700      |
|          |       |       |       | -4700 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 5000  |       |       |       | SF&TS   | 4995-5005      |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 5     |       |       |       |         |                |
|          | 167.5 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 5450  | ATC     | 5450-5480      |
|          |       |       |       | -5480 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 5480  | ATC     | 5480-5680      |
|          |       |       |       | -5680 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 5680  | 5680  | 5680  |       | A       | 5680-5683      |
|          |       |       |       |       | ERO-SAR |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 6        | 6215  | 6215  | 6215  |       | RTP-COM | 6215-6218      |
| 215-6218 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 6267.75  | 6268  | 6268  | 6268  |       | N       | 6              |
| -6268.25 |       |       |       |       | BDP-COM | 267.75-6268.25 |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 6282  |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 6311.75  | 6312  | 6312  | 6312  |       | DSC     | 6              |
| -6312.25 |       |       |       |       |         | 311.75-6312.25 |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       | 6314  |       |       | MSI-HF  |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 6525  | ATC     | 6525-6685      |
|          |       |       |       | -6685 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 8257  |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 8        | 8291  | 8291  | 8291  |       | RTP-COM | 8291-8294      |
| 291-8294 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 8     |       |       |       |         |                |
|          | 357.5 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 8        | 8364  |       | 8364  |       | S       | 8361-8367      |
| 362-8366 |       |       |       |       | urvival |                |
|          |       |       |       |       | Craft   |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 8376.25  | 8375, | 8     | 8     |       | N       | 8              |
| -8386.75 | 8376. | 376.5 | 376.5 |       | BDP-COM | 376.25-8386.75 |
|          | 25-83 |       |       |       |         |                |
|          | 86.75 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 8414.25  | 8414  | 8     | 8     |       | DSC     | 8              |
| -8414.75 |       | 414.5 | 414.5 |       |         | 414.25-8414.75 |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       | 8     |       |       | MSI-HF  |                |
|          |       | 416.5 |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 8815  | ATC     | 8815-8965      |
|          |       |       |       | -8965 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 10000 |       |       |       | SF&TS   | 9995-10005     |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 1     | ATC     | 10005-10100    |
|          |       |       |       | 0005- |         |                |
|          |       |       |       | 10100 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 1     | ATC     | 11275-11400    |
|          |       |       |       | 1275- |         |                |
|          |       |       |       | 11400 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 122      | 12290 | 12290 | 12290 |       | RTP-COM | 12290-12293    |
| 90-12293 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 12392 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 1        | 12520 | 12520 | 12520 |       | N       | 125            |
| 2519.75- |       |       |       |       | BDP-COM | 19.75-12520.25 |
| 12520.25 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 12563 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 1        | 12577 | 12577 | 12577 |       | DSC     | 125            |
| 2576.75- |       |       |       |       |         | 76.75-12577.25 |
| 12577.25 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       | 12579 |       |       | MSI-HF  |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 1     | ATC     | 13260-13360    |
|          |       |       |       | 3260- |         |                |
|          |       |       |       | 13360 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 133      | 1     |       |       |       | Radio   | 13360-13410    |
| 60-13410 | 3360- |       |       |       | As      |                |
|          | 13410 |       |       |       | tronomy |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 15000 |       |       |       | SF&TS   | 14990-15010    |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 16000 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 164      | 16420 | 16420 | 16420 |       | RTP-COM | 16420-16423    |
| 20-16423 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 16522 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 1        | 16695 | 16695 | 16695 |       | N       | 166            |
| 6694.75- |       |       |       |       | BDP-COM | 94.75-16695.25 |
| 16695.25 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 16750 |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 1        | 16804 | 16    | 16    |       | DSC     | 168            |
| 6804.25- |       | 804.5 | 804.5 |       |         | 04.25-16804.75 |
| 16804.75 |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       | 16    |       |       | MSI-HF  |                |
|          |       | 806.5 |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 1     | ATC     | 17900-17970    |
|          |       |       |       | 7900- |         |                |
|          |       |       |       | 17970 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       | 19    |       |       | MSI-HF  |                |
|          |       | 680.5 |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 20000 |       |       |       | SF&TS   | 19990-20010    |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       |       |       | 2     | ATC     | 21924-22000    |
|          |       |       |       | 1924- |         |                |
|          |       |       |       | 22000 |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       | 22376 |       |       | MSI-HF  |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          | 25000 |       |       |       | SF&TS   |                |
|          |       |       |       |       | (Not    |                |
|          |       |       |       |       | Cu      |                |
|          |       |       |       |       | rrently |                |
|          |       |       |       |       | Used)   |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 255      | 2     |       |       |       | Radio   | 25500-25670    |
| 00-25670 | 5500- |       |       |       | As      |                |
|          | 25670 |       |       |       | tronomy |                |
+----------+-------+-------+-------+-------+---------+----------------+
|          |       | 26    |       |       | MSI-HF  |                |
|          |       | 100.5 |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 37       |       |       |       |       | Radio   | 37.5-38.25 MHz |
| .5-38.25 |       |       |       |       | As      |                |
| MHz      |       |       |       |       | tronomy |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 73-74.6  |       |       |       |       | Radio   | 73.0-74.6 MHz  |
| MHz      |       |       |       |       | As      |                |
|          |       |       |       |       | tronomy |                |
+----------+-------+-------+-------+-------+---------+----------------+
| 7        |       |       |       |       | Aeron   | 74.8-75.2 MHz  |
| 4.8-75.2 |       |       |       |       | autical |                |
| MHz      |       |       |       |       | --      |                |
|          |       |       |       |       | Ins     |                |
|          |       |       |       |       | trument |                |
|          |       |       |       |       | Landing |                |
|          |       |       |       |       | System  |                |
|          |       |       |       |       | Marker  |                |
|          |       |       |       |       | Beacons |                |
+----------+-------+-------+-------+-------+---------+----------------+
| **L      |       |       |       |       |         |                |
| egend:** |       |       |       |       |         |                |
|          |       |       |       |       |         |                |
| AERO-SAR |       |       |       |       |         |                |
| =        |       |       |       |       |         |                |
| Aero     |       |       |       |       |         |                |
| nautical |       |       |       |       |         |                |
| Search   |       |       |       |       |         |                |
| and      |       |       |       |       |         |                |
| Rescue   |       |       |       |       |         |                |
|          |       |       |       |       |         |                |
| ATC =    |       |       |       |       |         |                |
| Air      |       |       |       |       |         |                |
| Traffic  |       |       |       |       |         |                |
| Control  |       |       |       |       |         |                |
|          |       |       |       |       |         |                |
| DSC =    |       |       |       |       |         |                |
| Digital  |       |       |       |       |         |                |
| S        |       |       |       |       |         |                |
| elective |       |       |       |       |         |                |
| Calling  |       |       |       |       |         |                |
|          |       |       |       |       |         |                |
| MSI-HF = |       |       |       |       |         |                |
| Marine   |       |       |       |       |         |                |
| Safety   |       |       |       |       |         |                |
| Inf      |       |       |       |       |         |                |
| ormation |       |       |       |       |         |                |
| -- High  |       |       |       |       |         |                |
| F        |       |       |       |       |         |                |
| requency |       |       |       |       |         |                |
|          |       |       |       |       |         |                |
| NBDP-COM |       |       |       |       |         |                |
| = Narrow |       |       |       |       |         |                |
| Band     |       |       |       |       |         |                |
| Direct   |       |       |       |       |         |                |
| Printing |       |       |       |       |         |                |
| --       |       |       |       |       |         |                |
| Commun   |       |       |       |       |         |                |
| ications |       |       |       |       |         |                |
|          |       |       |       |       |         |                |
| RTP-COM  |       |       |       |       |         |                |
| = Radio  |       |       |       |       |         |                |
| T        |       |       |       |       |         |                |
| elephony |       |       |       |       |         |                |
| --       |       |       |       |       |         |                |
| Commun   |       |       |       |       |         |                |
| ications |       |       |       |       |         |                |
|          |       |       |       |       |         |                |
| SF&TS =  |       |       |       |       |         |                |
| Standard |       |       |       |       |         |                |
| F        |       |       |       |       |         |                |
| requency |       |       |       |       |         |                |
| and Time |       |       |       |       |         |                |
| Signal   |       |       |       |       |         |                |
+----------+-------+-------+-------+-------+---------+----------------+

**4.7** **CONCLUSION**

Frequencies between 1.7 MHz and 80 MHz are allocated to a total of 13
radio services, with the Federal Government using all but two, in
varying degrees, to satisfy various mandated mission requirements.
Federal agencies currently have over 59,000 frequency assignments in
this frequency range. Allocations for the fixed and mobile services
accommodate communications for homeland security, distress and safety,
and other critical functions. These communications occupy over one-half
of the frequency range and were chosen as the focus of this Phase 1
study. Characteristics of fixed and mobile equipment can largely be
grouped into uses below 30 MHz and above 30 MHz and the equipment
characteristics show considerable consistency within these two
categories.

Both NTIA and FCC have long recognized that certain frequencies or bands
in the radio spectrum require special protection from interference
because of the critical or sensitive functions they support, including
distress and safety, radio astronomy, radionavigation, and others. NTIA
identified forty-one (41) such frequency bands between 1.7 MHz and 80
MHz, totaling approximately 4.2 MHz (5.4% of the total spectrum under
study), and proposes that they receive special protection from
interference by licensed and/or unlicensed transmitters.

[^1]: Some bands are grouped together.

[^2]: Note that the combined percentage of spectrum for all the radio
    services exceeds 100 % of the total spectrum in the band. This is
    because a band could be allocated to two or more radio services.

[^3]: Statistics on frequency assignments are current as of October
    2003.

[^4]: ^36^ ITU RR AP13-8 "\... any emission capable of causing harmful
    interference to distress, alarm, urgency or safety communications
    \[on these frequencies\] is prohibited."