**APPENDIX C**

**CHARACTERIZATION OF FEDERAL GOVERNMENT SPECTRUM USAGE AND OPERATIONS,
REPRESENTATIVE SYSTEMS AND TYPICAL PARAMETERS**

**C.1 INTRODUCTION**

As summarized in Section 4, the 1.7-80 MHz frequency range hosts a
number of radio services and supports well over one-hundred-thousand
Federal Government RF systems. Frequencies in this range are intensively
used on the bases of time-and geographic-sharing by several radio
systems. This appendix provides a more detailed discussion on federal
spectrum usage and operations under each radio service. In addition,
this appendix provides a general characterization of Federal Government
RF systems that includes presentation of representative federal systems
and typical system parameters.

The main data sources used in the description of the Federal Government
RF systems, spectrum usage and, in some cases, the radio services are
the Government Master File (GMF), federal agencies' inputs, and an
earlier NTIA study.[^1] Section C.2 discusses the nature of relevant
radio services and their allocations in the 1.7-80 MHz band. Special
systems are described in Section C.3, and special operating
considerations are summarized in Section C.4.

**C.2 SERVICES AND EXAMPLE SYSTEMS**

**C.2.1** **Fixed Service (1.7-29.7 MHz)**

The use of radio frequencies below 30 MHz for domestic fixed service by
the Federal Government is delineated in Section 8.2.11 of the NTIA
Manual. An excerpt from the NTIA Manual regarding the use of fixed
service below 30 MHz by the Federal Government is presented in Section
C.4. The frequency bands allocated to the fixed service in the 1.7-30
MHz band are shown in Table C-1.

In general, the Federal Government fixed service applications include
voice and data transmissions over intermediate and long-range distances
(25 km to over 2,000 km). Many fixed stations are located in the
vicinity of power lines which could eventually be used by BPL systems
(*e.g.*, *see* Figure C-1). The DOD, for example, uses HF radios on
military installations, both for ground and skywave modes of operations,
on or near major urban environments. The DOJ and DHS employ fixed
systems throughout the United States, including urban and suburban
areas, in support of law enforcement activities.

**Table C-1: Frequency Bands Allocated to the Fixed Service in the
1.7-30 MHz Band**

<table>
<colgroup>
<col style="width: 14%" />
<col style="width: 8%" />
<col style="width: 1%" />
<col style="width: 14%" />
<col style="width: 9%" />
<col style="width: 2%" />
<col style="width: 14%" />
<col style="width: 9%" />
<col style="width: 1%" />
<col style="width: 14%" />
<col style="width: 10%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
<td rowspan="13"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
<td rowspan="13"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
<td rowspan="13"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
</tr>
<tr class="even">
<td>1705-1800</td>
<td>95</td>
<td>5730-5900</td>
<td>170</td>
<td>13410-13570</td>
<td>160</td>
<td>19029-19680</td>
<td>651</td>
</tr>
<tr class="odd">
<td>2000-2065</td>
<td>65</td>
<td>5900-5950</td>
<td>50</td>
<td>13570-13600</td>
<td>30</td>
<td>19800-19990</td>
<td>190</td>
</tr>
<tr class="even">
<td>2107-2170</td>
<td>63</td>
<td>6765-7000</td>
<td>235</td>
<td>13800-13870</td>
<td>70</td>
<td>20010-21000</td>
<td>990</td>
</tr>
<tr class="odd">
<td>2194-2495</td>
<td>301</td>
<td>7300-7350</td>
<td>50</td>
<td>13870-14000</td>
<td>130</td>
<td>21850-21924</td>
<td>74</td>
</tr>
<tr class="even">
<td>2505-2850</td>
<td>345</td>
<td>7350-8100</td>
<td>750</td>
<td>14350-14990</td>
<td>640</td>
<td>22855-23000</td>
<td>145</td>
</tr>
<tr class="odd">
<td>3155-3230</td>
<td>75</td>
<td>9040-9500</td>
<td>460</td>
<td>15600-15800</td>
<td>200</td>
<td>23000-23200</td>
<td>200</td>
</tr>
<tr class="even">
<td>3230-3400</td>
<td>170</td>
<td>9900-9995</td>
<td>95</td>
<td>15800-16360</td>
<td>560</td>
<td>23350-24890</td>
<td>1540</td>
</tr>
<tr class="odd">
<td>4438-4650</td>
<td>212</td>
<td>10150-11175</td>
<td>1025</td>
<td>17410-17480</td>
<td>70</td>
<td>25330-25550</td>
<td>220</td>
</tr>
<tr class="even">
<td>4750-4850</td>
<td>100</td>
<td>11400-11600</td>
<td>200</td>
<td>17480-17550</td>
<td>70</td>
<td>26480-26950</td>
<td>470</td>
</tr>
<tr class="odd">
<td>4850-4995</td>
<td>145</td>
<td>11600-11650</td>
<td>50</td>
<td>18030-18068</td>
<td>38</td>
<td>27540-28000</td>
<td>460</td>
</tr>
<tr class="even">
<td>5005-5060</td>
<td>55</td>
<td>12050-12100</td>
<td>50</td>
<td>18168-18780</td>
<td>612</td>
<td>---</td>
<td></td>
</tr>
<tr class="odd">
<td>5060-5450</td>
<td>390</td>
<td>12100-12230</td>
<td>130</td>
<td>18900-19020</td>
<td>120</td>
<td>---</td>
<td></td>
</tr>
<tr class="even">
<td colspan="11"><strong>Total Bandwidth = 12,030 kHz</strong></td>
</tr>
</tbody>
</table>

Both the DOJ and DHS HF systems that support law enforcement activities
in many cases use encryption in both ground and skywave modes of
operations.[^2] Some of these systems support crisis response teams,
including the Federal Government's SHARES network program that is
described below. The vast majority of fixed systems in this portion of
the spectrum operate in the simplex mode. Table C-2 shows the
representative technical characteristics of fixed systems in the 1.7-30
MHz band.

Many foreign governments operate HF fixed stations at their embassy and
mission facilities that typically are located in major cities throughout
the United States. While many of these operations may backup or
supplement other means of communications, these HF systems become
critical sole means of communications in certain times of crises.

[**SHARES**.]{.underline} The mission of the shared resources (SHARES)
network is to provide backup or supplemental communications for exchange
of critical information among federal entities during certain crisis
situations. Normally, frequency assignments that support the SHARES
network are nationwide or assigned under the United States and
Possessions (US&P) category. The HF portion of the spectrum is most
suitable for the operation of the SHARES network because it offers a
medium in which a reliable, geographically expansive network can be
established, without satellites, using easy to implement equipment
operating over a range of frequencies (Federal Government satellite
facilities are used for other purposes in certain times of crises). A
summary of the emergency use of Federal Government HF frequencies for
the SHARES program is provided in Section C.4.2.

![](media/image1.png){width="6.5in" height="4.875in"}

Figure C-1: An Example of a Federal Government Radio Antenna near Power
Lines.

**Table C-2: Typical Technical Characteristics of Fixed Systems (1.7-30
MHz Band)**

+--------+--------+-------+--------+--------+--------------------------+
| **Sy   | **Ban  | *     | **Ant. | **Ant. | **Modulations**          |
| stem** | dwidth | *Ant. | Height | T      |                          |
|        | (      | Gain  | (ft)** | ype/** |                          |
|        | kHz)** | (d    |        |        |                          |
|        |        | Bi)** |        | **Po   |                          |
|        |        |       |        | lariza |                          |
|        |        |       |        | tion** |                          |
+--------+--------+-------+--------+--------+--------------------------+
| T      | 2.8    | 0-2   | 30-140 | D      | Analog, single channel,  |
| ypical |        |       |        | ipole/ | suppressed carrier,      |
| Fx     |        |       |        |        | telephony                |
|        |        |       |        | V& H   |                          |
+--------+--------+-------+--------+--------+--------------------------+

**C.2.2 Fixed Service (29.7-80 MHz)**

There are twelve fixed service bands, as shown in Table C-3, allocated
to the Federal Government to support federal fixed service requirements
in the 29.7-80 MHz band. The fixed systems operated by the federal
non-military agencies in this frequency range normally compliment the
mobile or land mobile service. They provide relay connectivity (repeater
stations) to hand held and vehicular mobile phones used by the federal
agencies for: management, protection, and preservation of the natural
resources; search and rescue operations; and law enforcement activities.
These fixed systems are also used for: exchange of meteorological data;
detection of unauthorized vehicular traffic, such as on or near shuttle
landing areas; and for fire alarm supervisory systems at various
facilities.

**Table C-3: Frequency Bands Allocated to the Federal Government for\
Fixed Service in the 29.7-80 MHz Band**

<table>
<colgroup>
<col style="width: 13%" />
<col style="width: 9%" />
<col style="width: 1%" />
<col style="width: 14%" />
<col style="width: 9%" />
<col style="width: 1%" />
<col style="width: 14%" />
<col style="width: 8%" />
<col style="width: 1%" />
<col style="width: 14%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p><strong>Frequency</strong></p>
<p><strong>(MHz)</strong></p></td>
<td><strong>BW (MHz)</strong></td>
<td rowspan="4"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(MHz)</strong></p></td>
<td><strong>BW (MHz)</strong></td>
<td rowspan="4"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(MHz)</strong></p></td>
<td><strong>BW (MHz)</strong></td>
<td rowspan="4"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(MHz)</strong></p></td>
<td><strong>BW (MHz)</strong></td>
</tr>
<tr class="even">
<td>29.89-29.91</td>
<td>0.02</td>
<td>34-35</td>
<td>1.0</td>
<td>38.25-39</td>
<td>0.75</td>
<td>49.6-50</td>
<td>0.4</td>
</tr>
<tr class="odd">
<td>30-30.56</td>
<td>0.56</td>
<td>36-37</td>
<td>1.0</td>
<td>40-42</td>
<td>2.0</td>
<td>74.6-74.8</td>
<td>0.2</td>
</tr>
<tr class="even">
<td>32-33</td>
<td>1.0</td>
<td>38-38.25</td>
<td>0.25</td>
<td>46.6-47</td>
<td>0.4</td>
<td>75.2-75.4</td>
<td>0.2</td>
</tr>
<tr class="odd">
<td colspan="11"><strong>Total Bandwidth = 7.78 MHz</strong></td>
</tr>
</tbody>
</table>

The DOD also employs their fixed systems as repeaters for: land and air
networks; tactical and training purposes; and support of military bases
operations. These include tactical communications exercises for base
defense missions; command and control; law enforcement; remote control
of multiple cameras on test ranges; airfield lighting; and acoustic
range traffic lights. In addition, these fixed systems support research,
development, test and evaluation of DOD systems.

[**Federal Agencies' Repeaters (Relay Stations)**.]{.underline} The vast
majority of fixed systems used by the federal agencies in the 29.7-80
MHz band compliments or provides relay connectivity for land mobile
systems. The majority of the federal fixed assignments that support
relay operations are under the US&P category. Some of these assignments
are required for short term intermittent use at unspecified locations
and used for notification of planned regular operations. Typical
technical characteristics of these systems are provided in Table C-4.

**Table C-4: Typical Technical Characteristics of Fixed System (29.7-80
MHz Band)**

+-------+--------+-------+--------+----------+------------------------+
| **    | **Ban  | *     | **Ant. | **Ant.   | **Modulations**        |
| Fixed | dwidth | *Ant. | Height | Type/**  |                        |
| Syst  | (      | Gain  | (Ft)** |          |                        |
| ems** | kHz)** | (d    |        | **Polari |                        |
|       |        | Bi)** |        | zation** |                        |
+-------+--------+-------+--------+----------+------------------------+
| No    | 16     | 0-3   | 16-250 | Whip,    | Analog and digital,    |
| n-DoD |        |       |        | yagi,    | frequency modulated,   |
|       |        |       |        | c        | single channel, data   |
|       |        |       |        | ollinear | and telephony.         |
|       |        |       |        | &        |                        |
|       |        |       |        | di       |                        |
|       |        |       |        | pole/V&H |                        |
+-------+--------+-------+--------+----------+------------------------+
| DoD   | 16-40  | 0-2   | 10-400 | Whip,    | Analog and digital,    |
|       |        |       |        | dipole,  | frequency modulated,   |
|       |        |       |        | co       | single channel, data   |
|       |        |       |        | llinear, | and telephony.         |
|       |        |       |        | &        |                        |
|       |        |       |        | coa      |                        |
|       |        |       |        | xial/V&H |                        |
+-------+--------+-------+--------+----------+------------------------+

**C.2.3 Mobile Service**

A total of 42 bands are allocated to the Federal Government for mobile
service in the 1.7-80 MHz band. Of these, 13 bands provide secondary
allocation to the mobile service and 17 bands exclude the use of
aeronautical mobile service as indicated in Table C-5. Typical systems
parameters are described below.

**Table C-5**: Frequency Bands Allocated to the Mobile Service in the
1.7-80 MHz Band

<table>
<colgroup>
<col style="width: 15%" />
<col style="width: 8%" />
<col style="width: 1%" />
<col style="width: 16%" />
<col style="width: 8%" />
<col style="width: 1%" />
<col style="width: 16%" />
<col style="width: 8%" />
<col style="width: 1%" />
<col style="width: 14%" />
<col style="width: 8%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
<td rowspan="12"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
<td rowspan="12"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
<td rowspan="12"></td>
<td><p><strong>Frequency</strong></p>
<p><strong>(kHz)</strong></p></td>
<td><strong>BW (kHz)</strong></td>
</tr>
<tr class="even">
<td>1705-1800</td>
<td>95</td>
<td>5060-5450 <sup>*</sup></td>
<td>390 <sup>**</sup></td>
<td>14350-14990 <sup>*</sup></td>
<td>640 <sup>**</sup></td>
<td>34000-35000</td>
<td>1000</td>
</tr>
<tr class="odd">
<td>2000-2065</td>
<td>65</td>
<td>5730-5900</td>
<td>170 <sup>**</sup></td>
<td>18168-18780 <sup>*</sup></td>
<td>612</td>
<td>36000-37000</td>
<td>1000</td>
</tr>
<tr class="even">
<td>2107-2170</td>
<td>63</td>
<td>5900-5950</td>
<td>50 <sup>**</sup></td>
<td>20010-21000 <sup>*</sup></td>
<td>990</td>
<td>38000-38250</td>
<td>250</td>
</tr>
<tr class="odd">
<td>2173.5-2190.5</td>
<td>17</td>
<td>6765-7000 <sup>*</sup></td>
<td>235</td>
<td>23000-23200 <sup>*</sup></td>
<td>200 <sup>**</sup></td>
<td>38250-39000</td>
<td>750</td>
</tr>
<tr class="even">
<td>2194-2495</td>
<td>301</td>
<td>7300-7350 <sup>*</sup></td>
<td>50</td>
<td>23350-24890</td>
<td>1540 <sup>**</sup></td>
<td>40000-42000</td>
<td>2000</td>
</tr>
<tr class="odd">
<td>2505-2850</td>
<td>345</td>
<td>7350-8100 <sup>*</sup></td>
<td>750</td>
<td>25330-25550</td>
<td>220 <sup>**</sup></td>
<td>46600-47000</td>
<td>400</td>
</tr>
<tr class="even">
<td>3155-3230</td>
<td>75 <sup>**</sup></td>
<td>10150-11175 <sup>*</sup></td>
<td>1025 <sup>**</sup></td>
<td>26480-26950</td>
<td>470 <sup>**</sup></td>
<td>49600-50000</td>
<td>400</td>
</tr>
<tr class="odd">
<td>3230-3400</td>
<td>170 <sup>**</sup></td>
<td>13410-13570 <sup>*</sup></td>
<td>160 <sup>**</sup></td>
<td>27540-28000</td>
<td>460</td>
<td>74600-74800</td>
<td>200</td>
</tr>
<tr class="even">
<td>4438-4650</td>
<td>212 <sup>**</sup></td>
<td>13570-13600 <sup>*</sup></td>
<td>30 <sup>**</sup></td>
<td>29890-29910</td>
<td>20</td>
<td>75200-75400</td>
<td>200</td>
</tr>
<tr class="odd">
<td>4750-4850</td>
<td>100 <sup>**</sup></td>
<td>13800-13870 <sup>*</sup></td>
<td>70 <sup>**</sup></td>
<td>30000-30560</td>
<td>560</td>
<td>—</td>
<td>--</td>
</tr>
<tr class="even">
<td>4850-4995</td>
<td>145</td>
<td>13870-14000 <sup>*</sup></td>
<td>130 <sup>**</sup></td>
<td>32000-33000</td>
<td>1000</td>
<td>---</td>
<td>--</td>
</tr>
<tr class="odd">
<td colspan="11"><p><sup>* Mobile service is secondary in this
band</sup></p>
<p><sup>** The use of aeronautical mobile is prohibited in this
band.</sup></p>
<p><strong><sup>Total Bandwidth = 17,560 kHz</sup></strong></p></td>
</tr>
</tbody>
</table>

For the most part, federal mobile service requirements in this portion
of the spectrum include voice and data, which also encompass
intermediate and long-range operations. The military, for example, uses
HF mobile radios in ground wave modes (*e.g*., hundreds of kilometers)
and skywave modes (thousands of kilometers) the same way they use the
their fixed systems. The vast majority of military mobile radios
operations are for tactical training, including tactical communications
to ground units, ships and aircraft, base operations, and as back-ups or
supplements to satellite communications. Normal training occurs in
military bases which may be in the vicinity of power lines. Example
systems used by the DOD for training and tactical communications are
described below (AN/VRC-100 and SINCGARS).

The Coast Guard uses the HF and MF portions of the spectrum extensively
for sea and air operations that include monitoring distress calls, both
international and domestic digital selective calling including for
distress calls, and search and rescue operations along the coastal areas
of the United States. A total of about 160 base stations sites,
including command and control sites, in the United States are used for
these purposes. In addition, there are approximately 100 HF/MF-equipped
buoy tenders and other vessels that operate on inland waters, up rivers
and inshore along the coasts. These vessels/boats are frequently near
power lines.

The DOJ and the DHS substantially use mobile radios in the HF band. The
vast majority of these radios are dedicated for law enforcement or used
in support of emergency and crises responses; as such, these systems are
authorized to operate anywhere in the United States. Mobile radios
employed by both agencies use encryption technology and some use ALE. An
example system is the U.S. Customs Over the Horizon Enforcement Network
(COTHEN). A brief description of the COTHEN system is presented below.

[**Single-Channel Ground and Airborne Radio System
(SINCGARS)**.]{.underline} The SINCGARS is a family of VHF-FM combat net
radios which provide the primary means of command and control for
infantry, armor, and artillery units in the Army. It is capable of short
range or long range operation for voice or digital data communications.
The system's configurations include man-pack, vehicular, and airborne
units. These units can be used for single channel operation or in a
jam-resistant, frequency hopping mode which can be changed as needed.
When configured for use of low VHF frequencies, the system operates on
any of the 2320 channels between 30-88 MHz in 25 kHz increments and is
designed to survive a nuclear environment. The SINCGARS Program is
continuously evolving to provide the latest in improvements and
capabilities to the soldier and to meet the Army's objectives for
widespread digitization.

The SINCGARS system, which was once a conventional voice-only radio used
for communications up and down the chain of command, has evolved into a
software-defined, open architecture system with extensive networking
capabilities. It offers clear or secure voice and data communications
capabilities that provide situational awareness and transmit command and
control information across entire theaters of battle or control.[^3] A
handheld unit, an airborne unit (AN/ARC-210D), a man-pack
(AN/PRC-119F(V)), and various vehicular components (AN/VRC-90F(V),
AN/VRC-87F(V), AN/VRC-87F(V), AN/VRC-89F(V), AN/VRC-91F(V) and
VRC-92F(V)) are under production.[^4] The SINCGARS program office has
fielded more than 136,000 radios to training base and Army units
worldwide.[^5]

**[COTHEN.]{.underline}** This network became widely operational in
1985. Previously, only Custom's marine vessels were equipped with the
COTHEN radios; however, because of the success of this initial
deployment, the network now provides communications support for more
than 235 aircraft, numerous maritime interdiction vessels, several
command offices, and numerous allied agencies including the Coast Guard,
Drug Enforcement Administration, Border Patrol, Army, Navy, and Joint
Interagency Task Forces.

The network integrates radio, computer, and a tactical voice privacy
unit in a extremely reliable, state-of-the-art communications network
that meets the demanding requirements of Customs' tactical interdiction
aircraft and boats in their fight against smuggling activities. High
powered fixed station transmitters located across the United States are
connected to Customs' air, marine, and Special Agent In Charge (SAIC)
locations via dedicated telephone lines. Tactical interdiction platforms
equipped with COTHEN radio can place a call to any other platform or
office in the network thousands of miles away typically using an ALE
protocol. Units on the COTHEN network use encryption for most of the
voice communications. The COTHEN network uses frequencies throughout the
HF band in order to obtain both the needed capacity and frequency
diversity (*see* Section C.4.1).

**[AN/VRC-100 (V).]{.underline}** The Army's AN/VRC-100 (V) system works
in conjunction with the AN/ARC-220 (V) to provide air-to-ground,
ground-to-air, ground-to-ground, and air-to-air non-line of sight
communications with aircraft at low altitude (30 meters to ground level
in the HF band). These radios will support normal voice and encrypted
voice communications, as well as message data. The AN/VRC-100 (V) uses
multiple modulations and coding techniques and it uses an ALE tone
(8-ary frequency shift keying). Table C-6 shows typical technical
characteristics of mobile systems.

**C.2.4 Land Mobile Service**

For so many decades, the federal agencies land mobile requirements have
been fulfilled in the mobile bands listed in Table C-5. The vast
majority of federal agencies usage of the land mobile service are for:
national defense (DOD); law enforcement (*e.g.*, DHS and DOJ);
management and preservation of national resources; search and rescue;
and emergency and safety communications operations in national
seashores, lakes, forests, water resources, and wildlife refuge,
including Tribal Lands and reservations (*e.g.*, DOI and DOA). Frequency
assignments that support land mobile radios for law enforcement are
under the US&P category. The areas of operation for these radios include
the urban, suburban, and rural areas, both off-shore and in-land.
Operation of these land mobile radios typically occurs near power lines
that may be used for BPL systems.

**Table C-6: Typical** Technical Characteristics of Mobile Service in
the 1.7-80 MHz Band

+-------+-------+--------+------+-------+--------+-------------------+
| **M   | **    | *      | **   | *     | **Ant. | **Modulations**   |
| obile | Freq. | *Bandw | Ant. | *Ant. | T      |                   |
| Syst  | Ra    | idth** | Ga   | Hei   | ype/** |                   |
| ems** | nge** |        | in** | ght** |        |                   |
|       |       | **(    |      |       | **Po   |                   |
|       | **(M  | kHz)** | *    | *     | lariza |                   |
|       | Hz)** |        | *(dB | *(Ft) | tion** |                   |
|       |       |        | i)** | )**   |        |                   |
+-------+-------+--------+------+-------+--------+-------------------+
| Fx    | 1     | 2.8    | 0    | 3     | W      | Analog, single    |
| St    | .7-30 |        |      | 0-100 | hip/V& | channel.          |
| ation |       |        |      |       | H      | Suppressed        |
|       |       |        |      |       |        | carrier,          |
|       |       |        |      |       |        | telephony         |
+-------+-------+--------+------+-------+--------+-------------------+
| M     | 1     | 2      | 0-2  | 6-32  | Whip/V | Analog, single    |
| obile | .7-30 | .8-3.0 |      |       | & H    | channel.          |
| unit  |       |        |      |       |        | Suppressed        |
|       |       |        |      |       |        | carrier,          |
|       |       |        |      |       |        | telephony         |
+-------+-------+--------+------+-------+--------+-------------------+
| Fx    | 29    | 16     | 0-3  | 3     | Whip,  | Analog or         |
| St    | .7-80 |        |      | 0-400 | Dipo   | digital, single   |
| ation |       |        |      |       | le/V&H | channel,          |
|       |       |        |      |       |        | Frequency         |
|       |       |        |      |       |        | modulated,        |
|       |       |        |      |       |        | telephony and     |
|       |       |        |      |       |        | data.             |
+-------+-------+--------+------+-------+--------+-------------------+
| M     | 29    | 16     | 0    | 6-32  | Whip/V | Analog or         |
| obile | .7-80 |        |      |       |        | digital, single   |
| unit  |       |        |      |       |        | or multiple       |
|       |       |        |      |       |        | channels.         |
|       |       |        |      |       |        | Frequency         |
|       |       |        |      |       |        | Modulated,        |
|       |       |        |      |       |        | telephony and     |
|       |       |        |      |       |        | data              |
+-------+-------+--------+------+-------+--------+-------------------+

In some cases, especially in areas lacking adequate commercial telephone
facilities, alternative communications that involve the use of
non-government stations (*e.g.*, citizens radio service (CB)) are
provided by the federal agencies. Such uses are in accordance with Part
95 of the FCC Rules and Regulations. In a practical sense, these systems
typically may not be in areas where power lines are deployed.

The DOE's most prominent use of the HF spectrum is for secure
communications. The DOE's HF system provides a nationwide communications
capability to facilitate shipments in support of national defense. The
system supplements existing physical security measures by providing
normal and emergency communications between vehicles and the DOE's
operations office control center.[^6] The DOE also relies upon HF to
provide essential communications during periods of critical emergencies
around various DOE facilities throughout the United States. Typical
technical characteristics of land mobile systems in the 1.7-80 MHz band
are shown in Table C-7.

**Table C-7: Typical Technical Characteristics of Land Mobile Services
in the\
1.7-80 MHz Band**

+-------+-------+--------+------+-------+--------+-------------------+
| *     | **    | *      | *    | **An  | **A    | **Modulations**   |
| *Land | Freq. | *Bandw | *Ant | tenna | ntenna |                   |
| M     | Ra    | idth** | enna | Hei   | T      |                   |
| obile | nge** |        | Ga   | ght** | ype/** |                   |
| Syst  |       | **(    | in** |       |        |                   |
| ems** | **(M  | kHz)** |      | *     | **Po   |                   |
|       | Hz)** |        | *    | *(Ft) | lariza |                   |
|       |       |        | *(dB | )**   | tion** |                   |
|       |       |        | i)** |       |        |                   |
+-------+-------+--------+------+-------+--------+-------------------+
| Base  | 1     | 2.8    | 0    | 3     | Coll   | Analog or         |
| St    | .7-30 |        |      | 0-100 | inear, | digital, single   |
| ation |       |        |      |       | whip,  | channel.,         |
|       |       |        |      |       | dipo   | suppressed        |
|       |       |        |      |       | le/V&H | carrier,          |
|       |       |        |      |       |        | telephony and     |
|       |       |        |      |       |        | telegraphy        |
+-------+-------+--------+------+-------+--------+-------------------+
| M     | 1     | 2      | 0-2  | 6-32  | Wh     | Analog or         |
| obile | .7-30 | .8-3.0 |      |       | ip/V&H | digital, single   |
| Unit  |       |        |      |       |        | channel,          |
|       |       |        |      |       |        | suppressed        |
|       |       |        |      |       |        | carrier,          |
|       |       |        |      |       |        | telephony and     |
|       |       |        |      |       |        | telegraphy        |
+-------+-------+--------+------+-------+--------+-------------------+
| Base  | 29    | 16-25  | 0-3  | 3     | Coll   | Analog or         |
| St    | .7-80 |        |      | 0-400 | inear, | digital, single   |
| ation |       |        |      |       | whip,  | channel,          |
|       |       |        |      |       | dipo   | suppressed        |
|       |       |        |      |       | le/V&H | carrier,          |
|       |       |        |      |       |        | telephony and     |
|       |       |        |      |       |        | telegraphy        |
+-------+-------+--------+------+-------+--------+-------------------+
| M     | 29    | 16-25  | 0    | 6-32  | Whip/V | Analog or         |
| obile | .7-80 |        |      |       |        | digital, single   |
| Unit  |       |        |      |       |        | channel,          |
|       |       |        |      |       |        | suppressed        |
|       |       |        |      |       |        | carrier,          |
|       |       |        |      |       |        | telephony and     |
|       |       |        |      |       |        | telegraphy        |
+-------+-------+--------+------+-------+--------+-------------------+

**C.2.5 Maritime Mobile Service**[^7]

The maritime mobile bands in the 1.7-80 MHz frequency range allocated to
the Federal Government are shown in Table C-8. The Federal Government's
main users of the maritime mobile bands are the Coast Guard, Navy, DOI,
and the Department of Commerce (DOC).

The Coast Guard operates HF systems for communications between shore
stations and ships, and from ship-to-ship. These systems support command
and control communications with cutters, aircraft, and shore facilities
for various purposes including: off shore search and rescue; drug
interdiction; enforcement of laws and treaties; and Arctic and Antarctic
operations. Because of the Coast Guard's important role in the drug
interdiction, a significant increase in the use of HF systems for
air/ground and ship-to-shore communications has taken place over the
last few decades. The Coast Guard also relies on the HF band for
services such as distress and safety communications, broadcast of
maritime safety information, emergency medical assistance
communications, broadcast of weather observation reports, and receipt of
vessel position reports for safety purposes.

**Table C-8: Frequency Bands Allocated to the Federal Government for\
**Maritime Mobile Service in the 1.7-80 MHz Band

+---------------+-----+---+---------------+-----+---+--------------+-----+
| **Frequency   | *   |   | **Frequency   | **B |   | **Frequency  | **B |
| Band**        | *BW |   | Band**        | W** |   | Band**       | W** |
|               | (   |   |               |     |   |              |     |
| **(kHz)**     | kHz |   | **(kHz)**     | **( |   | **(kHz)**    | **( |
|               | )** |   |               | kHz |   |              | kHz |
|               |     |   |               | )** |   |              | )** |
+---------------+-----+---+---------------+-----+---+--------------+-----+
| 2065-2107     | 42  |   | 6200-6525     | 325 |   | 18780-18900  | 120 |
+---------------+-----+---+---------------+-----+---+--------------+-----+
| 2170-2173.5   | 3.5 |   | 8100-8195     | 95  |   | 19680-19800  | 120 |
+---------------+-----+---+---------------+-----+---+--------------+-----+
| 2190.5-2194   | 3.5 |   | 8195-8815     | 620 |   | 22000-22855  | 855 |
+---------------+-----+---+---------------+-----+---+--------------+-----+
| 4000-4063     | 63  |   | 12230-13200   | 970 |   | 25070-25210  | 140 |
+---------------+-----+---+---------------+-----+---+--------------+-----+
| 4063-4438     | 375 |   | 16360-17410   | 1   |   | 26100-26175  | 75  |
|               |     |   |               | 050 |   |              |     |
+---------------+-----+---+---------------+-----+---+--------------+-----+
| **Total       |     |   |               |     |   |              |     |
| Bandwidth     |     |   |               |     |   |              |     |
| (BW) = 4,857  |     |   |               |     |   |              |     |
| kHz**         |     |   |               |     |   |              |     |
+---------------+-----+---+---------------+-----+---+--------------+-----+

In addition, the Coast Guard has an HF network that ties its major bases
together, including bases in Alaska, throughout CONUS, Hawaii, Puerto
Rico, the U.S. Virgin Islands, and the trust territories of the Pacific
Ocean. The Coast Guard also has communication networks in the HF band to
support the Long Range Aid to Navigation-C (LORAN-C). Although, the
LORAN-C was earmarked for replacement by the Global Positioning System
(GPS), the existing LORAN-C chains will be maintained and upgraded, at
least till the year 2008, in the transition period to satellite-based
navigation.[^8]

The Coast Guard carefully monitors several protected HF channels 24
hours a day from several locations in the U.S. and its possessions for
distress and maritime safety information communications. Some of these
frequencies are used by the Global Maritime Distress and Safety System
(GMDSS). Table C-9 shows the specific frequencies monitored by the Coast
Guard for distress calling. Consistently over the last few decades, the
Coast Guard annually responded to about 2000 search and rescue cases
from boats and ships in trouble, where alerting is via frequencies
listed in Table C-9.

The Navy also has communication systems between shore stations and
ships, as well as ship-to-ship in the HF maritime mobile bands. Navy
uses include: communications support to hydrographic surveys; tanker
operations; weapon system testing; secure voice communications, and the
naval telecommunications system that provides command, control, and
communications for the Navy and Marine Corps operating forces. For the
Navy, the HF band provides major back-up and supplemental capabilities
for long distance emergency and war time communications and will
continue to be very important asset to the Navy for fleet-wide
communication needs.

**^Table\ C-9:\ Frequencies\ Monitored\ by\ Coast\ Guard\ for\ Distress\ and\ Safety\ Communications\ in\ the\ HF\ Band^**[^9]

+--------+------------+---+---------+------------+---+---------+--------+
| *      | **Usage**  |   | **Freq. | **Usage**  |   | **Freq. | **U    |
| *Freq. |            |   | (kHz)** |            |   | (kHz)** | sage** |
| (      |            |   |         |            |   |         |        |
| kHz)** |            |   |         |            |   |         |        |
+--------+------------+---+---------+------------+---+---------+--------+
| 2174.5 | > NBDP-COM |   | 6215    | RTP-COM    |   | 12577   | DSC    |
| ^\*^   |            |   | ^\*^    |            |   | ^\*^    |        |
+--------+------------+---+---------+------------+---+---------+--------+
| 2182   | RTP-COM    |   | 6268    | NBDP-COM   |   | 12579   | MSI    |
| ^\*^   |            |   | ^\*^    |            |   | ^\*^    |        |
+--------+------------+---+---------+------------+---+---------+--------+
| 2187.5 | DSC        |   | 6312    | DSC        |   | 16420   | R      |
| ^\*^   |            |   | ^\*^    |            |   | ^\*^    | TP-COM |
+--------+------------+---+---------+------------+---+---------+--------+
| 3023   | Aero-SAR   |   | 6314    | MSI        |   | 16695   | NB     |
|        |            |   |         |            |   | ^\*^    | DP-COM |
+--------+------------+---+---------+------------+---+---------+--------+
| 4125   | RTP-COM    |   | 8291    | RTP-COM    |   | 16804.5 | DSC    |
| ^\*^   |            |   | ^\*^    |            |   | ^\*^    |        |
+--------+------------+---+---------+------------+---+---------+--------+
| 4177.5 | NBDP-COM   |   | 8376.5  | NBDP-COM   |   | 16806.5 | MSI    |
| ^\*^   |            |   | ^\*^    |            |   |         |        |
+--------+------------+---+---------+------------+---+---------+--------+
| 4207.5 | DSC        |   | 8414.5  | DSC        |   | 19680.5 | MSI    |
| ^\*^   |            |   | ^\*^    |            |   |         |        |
+--------+------------+---+---------+------------+---+---------+--------+
| 4209.5 | MSI        |   | 8416.5  | MSI        |   | 22376   | MSI    |
+--------+------------+---+---------+------------+---+---------+--------+
| 4210   | MSI        |   | 12290   | RTP-COM    |   | 26100.5 | MSI    |
|        |            |   | ^\*^    |            |   |         |        |
+--------+------------+---+---------+------------+---+---------+--------+
| 5680   | Aero-SAR   |   | 12520   | NBDP-COM   |   | ---     | \--    |
|        |            |   | ^\*^    |            |   |         |        |
+--------+------------+---+---------+------------+---+---------+--------+
| ^\*^   |            |   |         |            |   |         |        |
| Except |            |   |         |            |   |         |        |
| pr     |            |   |         |            |   |         |        |
| ovided |            |   |         |            |   |         |        |
| in the |            |   |         |            |   |         |        |
| ITU    |            |   |         |            |   |         |        |
| Radio  |            |   |         |            |   |         |        |
| Regula |            |   |         |            |   |         |        |
| tions, |            |   |         |            |   |         |        |
| any    |            |   |         |            |   |         |        |
| em     |            |   |         |            |   |         |        |
| ission |            |   |         |            |   |         |        |
| c      |            |   |         |            |   |         |        |
| apable |            |   |         |            |   |         |        |
| of     |            |   |         |            |   |         |        |
| c      |            |   |         |            |   |         |        |
| ausing |            |   |         |            |   |         |        |
| h      |            |   |         |            |   |         |        |
| armful |            |   |         |            |   |         |        |
| interf |            |   |         |            |   |         |        |
| erence |            |   |         |            |   |         |        |
| to     |            |   |         |            |   |         |        |
| dis    |            |   |         |            |   |         |        |
| tress, |            |   |         |            |   |         |        |
| alarm, |            |   |         |            |   |         |        |
| u      |            |   |         |            |   |         |        |
| rgency |            |   |         |            |   |         |        |
| or     |            |   |         |            |   |         |        |
| safety |            |   |         |            |   |         |        |
| co     |            |   |         |            |   |         |        |
| mmunic |            |   |         |            |   |         |        |
| ations |            |   |         |            |   |         |        |
| on     |            |   |         |            |   |         |        |
| these  |            |   |         |            |   |         |        |
| frequ  |            |   |         |            |   |         |        |
| encies |            |   |         |            |   |         |        |
| is     |            |   |         |            |   |         |        |
| prohi  |            |   |         |            |   |         |        |
| bited. |            |   |         |            |   |         |        |
|        |            |   |         |            |   |         |        |
| **Leg  |            |   |         |            |   |         |        |
| end:** |            |   |         |            |   |         |        |
|        |            |   |         |            |   |         |        |
| NBDP = |            |   |         |            |   |         |        |
| Narrow |            |   |         |            |   |         |        |
| band   |            |   |         |            |   |         |        |
| direct |            |   |         |            |   |         |        |
| pr     |            |   |         |            |   |         |        |
| inting |            |   |         |            |   |         |        |
|        |            |   |         |            |   |         |        |
| COM =  |            |   |         |            |   |         |        |
| C      |            |   |         |            |   |         |        |
| ommuni |            |   |         |            |   |         |        |
| cation |            |   |         |            |   |         |        |
|        |            |   |         |            |   |         |        |
| RTP=   |            |   |         |            |   |         |        |
| Radio  |            |   |         |            |   |         |        |
| Tel    |            |   |         |            |   |         |        |
| ephony |            |   |         |            |   |         |        |
|        |            |   |         |            |   |         |        |
| DSC =  |            |   |         |            |   |         |        |
| D      |            |   |         |            |   |         |        |
| igital |            |   |         |            |   |         |        |
| Sel    |            |   |         |            |   |         |        |
| ective |            |   |         |            |   |         |        |
| C      |            |   |         |            |   |         |        |
| alling |            |   |         |            |   |         |        |
|        |            |   |         |            |   |         |        |
| Ae     |            |   |         |            |   |         |        |
| ro-SAR |            |   |         |            |   |         |        |
| =      |            |   |         |            |   |         |        |
| Aerona |            |   |         |            |   |         |        |
| utical |            |   |         |            |   |         |        |
| Search |            |   |         |            |   |         |        |
| and    |            |   |         |            |   |         |        |
| Rescue |            |   |         |            |   |         |        |
|        |            |   |         |            |   |         |        |
| MSI =  |            |   |         |            |   |         |        |
| Marine |            |   |         |            |   |         |        |
| Safety |            |   |         |            |   |         |        |
| Infor  |            |   |         |            |   |         |        |
| mation |            |   |         |            |   |         |        |
+--------+------------+---+---------+------------+---+---------+--------+

The DOI uses the HF maritime mobile bands for its U.S. Geological Survey
organization (USGS) in support of marine geology exploration and mapping
tasks. The DOI also has systems in the HF maritime mobile bands to
support communications for the Pacific trust territories of the United
States. This includes communications between the islands and ships, the
outer island dispensary communications system in the marshal Islands,
between islands in the Marianas group, and between islands in the
American-Samoan group.

The DOC uses HF maritime mobile systems to support ships and boats used
by the National Marine Fisheries Service and for communication links
between major fishery centers and research vessels of the National
Oceanic and Atmospheric Administration (NOAA) Corps Fleet. The National
Ocean Service has radio communication facilities in the HF band to
support ships and mobile field teams engaged in oceanographic and
marine, and geodetic survey activities.

[**GMDSS**.]{.underline} The GMDSS is a distress alerting and safety
communications system that relies on satellite and terrestrial
communications links, and has changed international communications
networking from being primarily ship-to-ship to ship-to-shore (Rescue
Coordination Center). In addition, the system provides for location
determination in cases where a radio operator does not have time to send
a complete SOS or MAYDAY call. Ships are required to receive broadcast
of maritime safety information via the GMDSS. In 1988, the International
Maritime Organization (IMO) amended the Safety of Life at Sea (SOLAS)
Convention, requiring most ships to be retrofitted with GMDSS equipment.
In the absence of interference, the GMDSS is able to reliably perform
the following functions: alerting, including position determination of
the unit in distress; search and rescue coordination; locating (homing);
maritime information broadcasts; general communications; and
bridge-to-bridge communications.

Section 5.4 of the NTIA Manual states that, "stations in the maritime
and other radio services employing frequencies and techniques used in
the GMDSS shall comply with the relevant ITU-R recommendations with
respect to the technical characteristics of, among others, digital
selective calling (DSC) distress call formats and . . . other broadcasts
of maritime safety information using narrow band direct-printing (NBDP)
in the bands 4-27.5 MHz." Additionally, such stations when using DSC
shall conform to the calling, acknowledgment, and operating procedures
for DSC contained in the ITU Radio Regulations (Article 32) and the
relevant ITU-R recommendations. Table C-10 provides typical technical
characteristics of maritime mobile systems in the HF band.

**Table C-10: Typical Technical Characteristics of Maritime Mobile
Systems\
(1.7-30 MHz Band)**

+-----+-------+-------+-------+-------+--------+---------------------+
| *   | **    | *     | *     | *     | **Ant. | **Modulations**     |
| *Sy | Freq. | *Band | *Ant. | *Ant. | Type/  |                     |
| ste | Band  | width | Gain  | H     | Po     |                     |
| m** | (M    | (k    | (d    | eight | lariza |                     |
|     | Hz)** | Hz)** | Bi)** | (     | tion** |                     |
|     |       |       |       | Ft)** |        |                     |
+-----+-------+-------+-------+-------+--------+---------------------+
| Dis | 2-30  | 2.8   | 0-2   | un    | Whip,  | Single              |
| tre |       |       |       | known | Cone/V | sideband-suppressed |
| ss/ |       |       |       |       |        | carrier, single     |
|     |       |       |       |       |        | channel, analog,    |
| SAR |       |       |       |       |        | telephony           |
| ^   |       |       |       |       |        |                     |
| \*^ |       |       |       |       |        |                     |
+-----+-------+-------+-------+-------+--------+---------------------+

^\*^ SAR = Search and Rescue.

**C.2.6 Broadcasting Service**

In the Federal Government, HF broadcasting from the U.S. is conducted by
the Broadcasting Board of Governors (BBG). The BBG has the mission to
promote understanding abroad of the United States, its policies, its
people, and its culture. HF radio is a very practical means of
communicating directly with the people of other nations because of the
extensive availability of inexpensive broadcast receivers. The BBG's
global radio network, the Voice of America (VOA), consists primarily of
two powerful HF transmitter sites (located in California and Virginia).

The power levels for equipment at VOA installation can be as high as 500
kW. The modulation designator typically is 10K00A3E. This accommodates a
10 kHz bandwidth signal, amplitude modulation, and audio communication.
A multi-band, curtain-array antenna is a representative type of antenna
for VOA broadcast installation.

While the intended receivers of the VOA's transmissions generally are
abroad there are numerous broadcasting receivers owned and operated by
foreign citizens and government personnel in the United States that
could be susceptible to BPL interference because of proximity to power
lines. Protecting other administrations' broadcasting is critical
because of reciprocity. The current ITU-R B-03, Seasonal Broadcasting
Schedule, shows multiple administrations broadcasting to the United
States for every timeframe within a 24- hour period.[^10]

The 18 bands allocated to the Federal Government for broadcasting
service in the HF portion of the spectrum are listed in Table C-11.
Because of frequency reuse capabilities inherent in HF broadcasting, one
should expect that broadcast receivers located in the United States are
tuned within these bands.

**Table C-11: Frequency Bands Allocated to the Federal Government for\
Broadcasting Service in the 1.**7-80 MHz Band

  ------------- ---------- ------------- ---------- ------------- ----------
  **Frequency   **BW       **Frequency   **BW       **Frequency   **BW
  (kHz)**       (kHz)**    (kHz)**       (kHz)**    (kHz)**       (kHz)**

  5900-5950     50         11650-12050   400        15600-15800   200

  5950-6200     250        12050-12100   50         17480-17550   70

  7300-7350     50         13570-13600   30         17550-17900   350

  9400-9500     100        13600-13800   200        18900-19020   120

  9500-9900     400        13800-13870   70         21450-21850   400

  11600-11650   50         15100-15600   500        25670-26100   430

  **Total                                                         
  Bandwidth                                                       
  (BW) = 3,720                                                    
  kHz**                                                           
  ------------- ---------- ------------- ---------- ------------- ----------

**C.2.7 Aeronautical Mobile Service**

The aeronautical mobile service is subdivided into two distinct radio
services; namely, aeronautical mobile route (R) and aeronautical mobile
off-route (OR) services. By definition, the aeronautical mobile (R)
service is reserved for communications relating to safety and regularity
of flight, primarily along national or international civil air routes;
while, the aeronautical mobile (OR) service is intended for other
communications, including those relating to flight coordination,
primarily outside national or international civil air routes.[^11] In
the 1.7-80 MHz band, a total of 21 bands are allocated to these services
with a total of 2176 kHz of spectrum. Out of the 2176 kHz of spectrum,
1331 kHz is dedicated for the aeronautical mobile (R) service and 845
kHz is assigned to aeronautical mobile (OR) service. In general, the
Federal Government frequency assignments in the bands allocated to the
aeronautical mobile service in this portion of the spectrum are used for
controlling aircraft traffic. Other uses in the United States may
include Airline Operational Control (AOC) communications of foreign air
carriers, including for scheduled traffic.

**C.2.7.1 Aeronautical Mobile (R) Service**

Frequency assignments to stations in the aeronautical mobile (R)
service, in the HF band, must be assigned in conformity with the
provisions and the allotment plan of Appendix 27 of the ITU Radio
Regulation (RR). Such assignments conform to the plan for the allotment
of frequencies to: (a) Major World Air Route Areas (MWARAs); (b)
Regional and Domestic Air Route Areas (RDARAs); (c) VOLMET Allotment
Areas; and (d) Worldwide Allotment Areas contained in Appendix 27 (RR)
or, to meet operational requirements not otherwise met by the Allotment
Plan, must comply with the provisions of Appendix 27 for the adaptation
of allotment procedures. Assignments in support of International Air
Routes (MWARA and VOLMET allotments) are also within the purview of
applicable International Civil Aviation Organization (ICAO) frequency
assignment plans that have been agreed internationally and are
recognized in the ITU RR.

As a matter of general policy, HF is not normally used for aeronautical
mobile (R) communications in the domestic services within the
conterminous United States, the need for such frequencies having been
generally eliminated through successful use of the VHF
communications.[^12] However, Appendix 27 (RR) Part II, Section I,
Article 2 provides for the allotment of frequencies to the RDARAs, which
include the conterminous United States, and also Alaska, Hawaii, Puerto
Rico, and the Virgin Islands. This then enables special aeronautical
communication requirements, not conforming fully to the definition of
the aeronautical mobile (R) service, to be satisfied by use of
frequencies from these allotments within the limitations of the national
criteria established jointly with the FCC.[^13] Section C.4.4 provides
these national criteria.

Certain frequencies in the HF band are available to all government
agencies for operational control and safety of civil government aircraft
in certain specified areas. These frequencies, as listed in Table C-12,
are intended for support of operations not exclusively en route in
nature. These frequencies were chosen so as to avoid those channels in
which operation might result in harmful interference to aeronautical
stations dedicated to the safety and regularity of flight.

**Table C-12**: Frequencies Designated for Operational Control of Civil
Government Aircraft

  ------------ ----------- ------------- -- ------------ ----------- -------------
  **Assigned   **Carrier   **Areas of       **Assigned   **Carrier   **Areas of
  Freq.        Freq.       Operation**      Freq.        Freq.       Operation**
  (kHz)**      (kHz)**                      (kHz)**      (kHz)**     

  2897.4       2896        AK, HI, CONUS    10055.4      10054       HI

  2948.4       2947        AK, HI, CONUS    11307.4      11306       CONUS

  3002.4       3001        AK, HI, CONUS    17950.4      7949        AK, HI, CONUS

  6539.4       6538        CONUS            21926.4      21925       AK, HI, CONUS

  8886.4       8885        CONUS            21929.4      21928       AK, HI, CONUS

  8910.4       8909        AK, HI, CONUS    21935.4      21934       AK, HI, CONUS
  ------------ ----------- ------------- -- ------------ ----------- -------------

The Federal Government aeronautical stations that operate in the
aeronautical mobile (R) service within the US&P are normally authorized
only for the Federal Aviation Administration

(FAA), mainly for its HF system called the National Radio Communications
System (NRCS). As such, Federal Government spectrum use of the
aeronautical mobile (R) service in the HF band is limited to few federal
agencies. For example, the DOI use of the aeronautical mobile (R)
service is mainly outside of the contiguous United States. Specifically,
their use is mostly in Alaska, Hawaii, and the trust territories of the
Mariana and Marshall Islands in the Pacific Ocean. Operations in the
trust territories include inter-island communications. In Alaska,
Hawaii, and CONUS, the DOI assignments are required for en route
communications and flight following of aircraft in support of national
resource programs.

Frequency assignments belonging to the Department of Treasury are used
for aircraft in support of law enforcement responsibilities. Table C-13
specifies the particular bands used for aeronautical mobile (R) and
respective bandwidths.

**Table C-13: Frequency Bands Allocated to the Aeronautical Mobile
Service (R) (1.7-3**0 MHz Band)

  -------------------- -------------- -- -------------------- --------------
  **Frequency (kHz)**  **Bandwidth       **Frequency          **Bandwidth
                       (kHz)**           (kHz)/Service**      (kHz)**

  2850-3025            175               10005-10100          95

  3400-3500            100               11275-11400          125

  4650-4700            50                13260-13360          100

  5450-5680            230               17900-17970          70

  6525-6685            160               21924-22000          76

  8815-8965            150               ---                  \-\--

  **Total Bandwidth =                                         
  1331 kHz**                                                  
  -------------------- -------------- -- -------------------- --------------

Table C-14 shows typical technical characteristics of Federal Government
systems in the aeronautical mobile (R) service.

**Table C-14: Typical Technical Characteristics of Aeronautical Mobile
(R) Systems** (1.7-30 MHz Band)

+--------+--------+-------+--------+---------+-------------------------+
| **Sy   | **Ban  | *     | **Ant. | **Ant.  | **Modulations**         |
| stem** | dwidth | *Ant. | Height | Type/** |                         |
|        | (      | Gain  | (Ft)** |         |                         |
|        | kHz)** | (d    |        | **      |                         |
|        |        | Bi)** |        | Polariz |                         |
|        |        |       |        | ation** |                         |
+--------+--------+-------+--------+---------+-------------------------+
| Ai     | 2.8    | 0     | 18000  | Conf    | Analog, single channel, |
| rborne |        |       | -40000 | ormal/V | suppressed carrier,     |
|        |        |       |        |         | telephony.              |
+--------+--------+-------+--------+---------+-------------------------+
| Ground | 2.8    | 0-3   | u      | Various | Analog, single channel, |
|        |        |       | nknown | /V      | suppressed carrier,     |
|        |        |       |        |         | telephony.              |
+--------+--------+-------+--------+---------+-------------------------+

**C.2.7.2 Aeronautical Mobile (OR) Service**

Frequencies in bands allocated exclusively to the (OR) service are
internationally alloted to countries by Appendix 26 of the ITU RR, which
also establishes frequency sharing criteria, protection ratios, and
other technical and operational principles. These principles recognize
the possible necessity for the adaptation of the allotment plan to meet
valid requirements of the various administrations, provided these
adaptations do not decrease the protection to frequencies assigned in
strict adherence to the plan.[^14]

Frequencies in the bands allocated exclusively to the (OR) service are
nationally used primarily for the satisfaction of military aeronautical
requirements. Assignments of frequencies in these bands are subject to
coordination with the Military Departments through the Interdepartment
Radio Advisory Committee (IRAC) mechanism.

Nationally, the use of the aeronautical mobile (OR) service bands is
mainly for military operations that include controlling traffic routes
and special military needs. The Navy and Air Force are the major users
of the aeronautical mobile (OR) bands. The vast majority of their
assignments are dedicated for air-ground-air communications provided by
the AN/ARC family of radios. The AN/ARC-190 is a typical radio used by
the Air Force in the HF band and is described below. Other uses of the
aeronautical mobile (OR) service bands by the Air force are: global
command and control stations required for air and ground communications;
flight testing; ground tactical communications; communications for the
Strategic Air Command (SAC) forces; data coordination; and de-orbiting
satellite recovery operations.

Table C-15 shows the frequency bands allocated to the aeronautical
mobile service (OR) in the 1.7-30 MHz band and Table C-16 shows a
typical technical characteristics of aeronautical mobile service (OR)
system in the HF band.

**Table C-15: Frequency Bands Allocated to the Aeronautical Mobile (OR)
Service (1.7-3**0 MHz Band)

  -------------------- -------------- -- -------------------- --------------
  **Frequency (kHz)**  **Bandwidth       **Frequency (kHz)**  **Bandwidth
                       (kHz)**                                (kHz)**

  3025-3155            130               11175-11275          100

  4700-4750            50                13200-13260          60

  5680-5730            50                15010-15100          90

  6685-6765            80                17970-18030          60

  8965-9040            75                23200-23350          150

  **Total Bandwidth =                                         
  845 kHz**                                                   
  -------------------- -------------- -- -------------------- --------------

[**AN/ARC-190**.]{.underline} The AN/ARC-190 works in conjunction with
the AN/TRC-181 to provide short-, medium-, and long-range voice and data
communications employing an automatic communications processor for auto
link and anti-jam capabilities. These systems employ multiple
modulations and coding techniques, including sideband suppressed
carrier, single sideband reduced or variable level carrier, continuous
wave employing frequency hopping and pseudo random pre-selection
technique.

Table C-16: Typical Technical Characteristics of Aeronautical Mobile
(OR) Systems (1.7-30 MHz Band)

+--------+--------+-------+--------+--------+--------------------------+
| **Sy   | **Ban  | *     | **Ant. | **Ant. | **Modulations**          |
| stem** | dwidth | *Ant. | Height | T      |                          |
|        | (      | Gain  | (ft)** | ype/** |                          |
|        | kHz)** | (d    |        |        |                          |
|        |        | Bi)** |        | **Po   |                          |
|        |        |       |        | lariza |                          |
|        |        |       |        | tion** |                          |
+--------+--------+-------+--------+--------+--------------------------+
| AN/ARC | 3.5    | 0.0   | 30,000 | B      | Analog and digital,      |
|        |        |       |        | lade/V | single channel, reduced  |
| (air   |        |       |        |        | or suppressed carrier,   |
| borne) |        |       |        |        | telephony and data.      |
+--------+--------+-------+--------+--------+--------------------------+
| AN/TRC | 3.5    | 0.0   | 6-32   | Whip/V | Analog and digital,      |
|        |        |       |        |        | single channel, reduced  |
| (g     |        |       |        |        | or suppressed carrier,   |
| round) |        |       |        |        | telephony and data.      |
+--------+--------+-------+--------+--------+--------------------------+

**C.2.8 Standard Frequency and Time Signal**[^15]

The Federal Government, via the National Institute of Standards and
Technology (NIST), has provided standard time and frequency services
since 1923 in the HF band. These services are important to a community
of technical users in support of basic activities such as navigation,
power generations, and communications. However, many of these HF
capabilities are being supplemented by the GPS. The services provided
include: time announcements; standard time intervals; standard
frequencies; geophysical alerts; marine storm warnings; Omega Navigation
System status report; Coordinated Universal Time (UTC) corrections; and
digital time code.

NIST provides time and frequency services at 2.5 MHz, 5 MHz, 10 MHz, 15
MHz, and 20 MHz. The services are broadcast from stations WWV, in Fort
Collins, CO, and from WWVH, in Kauai, HI. Table C-17 shows the radiated
power for the transmissions at each location. The antennas at WWV are
omnidirectional, half-wave dipoles. At WWVH, the antennas are phased
vertical half-wave dipole arrays with maximum gain in a westerly
direction. Double sideband amplitude modulation is employed at both
stations. Four modulation levels (25, 50, 75, and 100 percent) are used
depending on the particular information transmitted.

**Table C-17: Radiated Power for Transmissions at Stations WWV and
WWVH**

  ------------------- ------------------------- --------------------------
  **Frequency (MHz)** **Radiated Power at WWV   **Radiated Power at WWVH
  ^a^                 (kW)**                    (kW)**

  2.5                 10                        10

  10                  10                        10

  15                  10                        10

  20                  2.5                       \--
  ------------------- ------------------------- --------------------------

^a^ The 25 MHz is currently not in use.

As the GPS and other communications systems become more widely
assimilated, HF time broadcasts service may become obsolete. Currently,
the main users of the HF standard frequency and time signal services are
hobbyists, amateurs, and signal propagation researchers.

In the 1.7- 30 MHz frequency range, 13 bands are allocated to the
standard frequency and time signal radio service on a primary basis.
Table C-18 shows these bands and their respective bandwidths.

**Table C-18: Frequency Bands Allocated to the Standard Frequency and
Time Signal Service\
in the 1.7-3**0 MHz Band

  -------------------- -------------- -- -------------------- --------------
  **Frequency (kHz)**  **Bandwidth       **Frequency (kHz)**  **Bandwidth
                       (kHz)**                                (kHz)**

  2495-2505            10                14990-15010          20

  4995-5005            10                19990-20010          20

  9995-10005           10                24990-25010          20

  **Total Bandwidth =                                         
  90 kHz**                                                    
  -------------------- -------------- -- -------------------- --------------

**C.2.9 Aeronautical Radionavigation**

In the 1.7-80 MHz frequency range, the 74.8-75.2 MHz band is allocated
to the aeronautical radionavigation service. The federal agencies that
operate on this band are the Air Force, Army and the FAA. Basically, use
of this band is for marker beacons that provide navigational aids,
including the Instrumentation Landing System (ILS). Marker beacons
provide the pilot a reliable altitude indicator as it approaches the
runway (barometric altimeters are not accurate at low altitudes). Most
ILS and localizer landing approaches incorporate at least one marker and
as many as three. The first marker (Outer Marker) is anywhere from four
to 10 miles from the end of a runway and, normally, supports navigation
for the initial approach. The marker beacon transmit in the
ground-to-air direction at 75 MHz and is modulated with a 400 Hz
intermit tone. The second marker (Middle Marker) is normally used about
3,000 feet off the end of the landing runway. The Middle Marker is
normally used about 200 feet above ground level. This marker is
transmitted at 75 MHz with a 1,300 Hz tone modulation. The third marker
(Inner Marker) is normally installed around 1,000 feet from the end of
the runway. Again, the transmit frequency is 75 MHz but the tone is at
3,000 Hz.[^16]

ITU RR No. 5.180 states that,

> "The frequency 75 MHz is assigned to marker beacons. Administrations
> shall refrain from assigning frequencies close to the limits of the
> guardband to stations of other services which, because of their power
> or geographical position, might cause harmful interference or
> otherwise place a constraint on marker beacons. Every effort should be
> made to improve further the characteristics of airborne receivers and
> to limit the power of transmitting stations close to the limits
> 74.8-75.2 MHz."

About 98 percent of the federal assignments that support marker beacons
operation belong to the FAA. Because many major airports are within the
vicinity of metropolitan or urban areas, BPL operations generally should
not be considered in the 74.8-75.2 MHz band. Typical technical
characteristics of aeronautical radionavigation systems operating in the
7.4-75.2 MHz band are shown in Table C-19.

**Table C-19: Typical Technical Characteristics of Radionavigation
Systems in the** 74.8-75.2 MHz Band

+--------+--------+-------+--------+--------+--------------------------+
| **Sy   | **Ban  | *     | **Ant. | **Ant. | **Modulations**          |
| stem** | dwidth | *Ant. | Height | T      |                          |
|        | (      | Gain  | (Ft)** | ype/** |                          |
|        | kHz)** | (d    |        |        |                          |
|        |        | Bi)** |        | **Po   |                          |
|        |        |       |        | lariza |                          |
|        |        |       |        | tion** |                          |
+--------+--------+-------+--------+--------+--------------------------+
| Marker | 0.8-6  | -2.   | 0-3000 | B      | Amplitude modulation,    |
|        |        | 5-2.0 |        | lade/H | double sideband, single  |
| Beacon |        |       |        |        | channel, digital and     |
|        |        |       |        |        | telegraphy               |
+--------+--------+-------+--------+--------+--------------------------+

**C.2.10 Radiolocation Service**

The radiolocation service is a radiodetermination service used for
detection and positional location of distant objects (targets).[^17]
There are three bands allocated to the radiolocation service in the
1.7-80 MHz range, as shown in Table C-20.

**Table C-20: Frequency Bands Allocated to the Radiolocation Service
(1.7-80 MHz Band)**

  ----------------------- ----------------------- -----------------------
  **Frequency Band        **Bandwidth (kHz)**     **Allocation**
  (kHz)**                                         

  1705-1800               95                      Primary

  1900-2000               100                     Primary

  3230-3400               170                     Secondary
  ----------------------- ----------------------- -----------------------

In these bands, three federal entities (Navy, Army, and Tennessee Valley
Authority (TVA)) are currently employing radiolocation systems. The Navy
uses these bands in support of fleet operations and for surveillance.
Specifically, the Navy's radiolocation systems provide position fixing
in support of mine countermeasure operations and long range
surveillance. For surveillance, the Navy employs a long range,
re-locatable over the horizon radar system (AN/TPS-71). This system is
described further in Section C.4. The Army has multiple radiolocation
requirements in these bands, namely, for test range and off-shore
operations, including such as; target scoring; hydrographic surveys; and
for determining location of missile payloads during recovery operations.
The TVA has two radiolocation assignments for establishing boat
positions while conducting water quality surveys in the vicinity of
thermal-electric generation plants in TVA service areas. Typical
technical characteristics of a radiolocation system in the 1.7-80 MHz
band are presented in Table C-21.

**Table C-21: Representative Technical Characteristics of Radiolocation
Systems** in the 1.7-80 MHz Band

+--------+--------+-------+--------+--------+-------------------------+
| **     | **Ban  | *     | **Ant. | **Ant. | **Modulations**         |
| System | dwidth | *Ant. | Height | T      |                         |
| Sta    | (      | Gain  | (ft)** | ype/** |                         |
| tion** | kHz)** | (d    |        |        |                         |
|        |        | Bi)** |        | **Po   |                         |
|        |        |       |        | lariza |                         |
|        |        |       |        | tion** |                         |
+--------+--------+-------+--------+--------+-------------------------+
| Land & | 0.001  | 0-3   | u      | unk    | Amplitude modulation,   |
| Ship   | -0.600 |       | nknown | nown/V | double sideband, single |
|        |        |       |        |        | channel, digital and    |
|        |        |       |        |        | telegraphy              |
+--------+--------+-------+--------+--------+-------------------------+

**C.2.11 Amateur and Amateur-Satellite Services**

The amateur service is a radiocommunication service for the purpose of
self-training, inter-communication and technical investigation that is
used by duly authorized persons interested in radio techniques solely
with a personal aim and without pecuniary interest.[^18] Amateur radio
operators' licenses are granted by the FCC and uses must adhere to
technical standards as given in the FCC Rules and Regulations, Part 97
--- Amateur Radio Service. The Amateur-satellite service is a
radiocommunication service using space stations on earth satellites for
the same purposes as those of the amateur service.[^19]

Amateur radio operators extensively assist the law enforcement community
and other public service organizations during all kinds of emergencies
including: hurricanes, earthquakes, tornadoes and floods, motorist
accidents, fires and chemical spills, and search and rescue
operations.[^20]

There are 13 bands allocated to the amateur and amateur-satellite
services (1.7-80 MHz band). The majority of these bands is in the lower
portion of the HF band and is presented in Table C-22.

**Table C-22: Frequency Bands Allocated to the Amateur and
Amateur-Satellite Services\
in the 1.7-80 MHz Band**

+------------------+-------------------+------------+-----------------+
| **Frequency Band | **Radio Service** | *          | **Total         |
| (kHz)**          |                   | *Bandwidth | Bandwidth       |
|                  |                   | (kHz)**    | (kHz)**         |
+------------------+-------------------+------------+-----------------+
| 1800-1900        | Amateur           | 100        | Amateur = 7650  |
|                  |                   |            |                 |
|                  |                   |            | Amateur-        |
|                  |                   |            |                 |
|                  |                   |            | Satellite =     |
|                  |                   |            | 2700            |
+------------------+-------------------+------------+-----------------+
| 3500-4000        | Amateur           | 500        |                 |
+------------------+-------------------+------------+-----------------+
| 7000-7100        | Amateur/          | 100        |                 |
|                  | Amateur-Satellite |            |                 |
+------------------+-------------------+------------+-----------------+
| 7100-7300        | Amateur           | 200        |                 |
+------------------+-------------------+------------+-----------------+
| 10100-10150      | Amateur           | 50         |                 |
+------------------+-------------------+------------+-----------------+
| 14000-14250      | Amateur/          | 250        |                 |
|                  | Amateur-Satellite |            |                 |
+------------------+-------------------+------------+-----------------+
| 14250-14350      | Amateur           | 100        |                 |
+------------------+-------------------+------------+-----------------+
| 18068-18168      | Amateur/          | 100        |                 |
|                  | Amateur-Satellite |            |                 |
+------------------+-------------------+------------+-----------------+
| 21000-21450      | Amateur/          | 450        |                 |
|                  | Amateur-Satellite |            |                 |
+------------------+-------------------+------------+-----------------+
| 24890-24990      | Amateur/          | 100        |                 |
|                  | Amateur-Satellite |            |                 |
+------------------+-------------------+------------+-----------------+
| 28000-29700      | Amateur/          | 1700       |                 |
|                  | Amateur-Satellite |            |                 |
+------------------+-------------------+------------+-----------------+
| 50000-54000      | Amateur           | 4000       |                 |
+------------------+-------------------+------------+-----------------+

The DOD administers the Military Affiliate Radio System (MARS). The MARS
is managed and operated by the Army, Navy and the Air Force. The MARS
program consists of civilian and military licensed amateur radio
operators who are interested in supporting military communications. The
MARS volunteer force includes more than 5,000 dedicated and skilled
amateur radio operators.[^21] They contribute to the MARS mission
providing auxiliary or emergency communications on a local, national,
and international basis as an adjunct to normal communications.[^22] The
radios used in the MARS program are the same or equivalent systems used
by the amateur radio operators.

The MARS system continues to play an important role in the military for:
(1) helping to maintain morale through assistance in the maintenance of
contacts with spouses or friends even when the distance separation is
great, and (2) when needed, it can augment emergency communication
services within the military. The morale of servicemen and women is
always an important area of concern for military commanders,
particularly for personnel stationed in remote areas away from family
and friends. Another area of concern for the military is to maintain an
independent system that can be used in time of war, emergencies or other
national disasters in ready-to-use condition. The MARS HF network is
constantly being tested by calls made by the military personnel. Another
benefit of this active system is as a training tool for reservists and
active duty servicemen on a system they may be called upon to operate in
an emergency situation.[^23] Typical technical characteristics of a MARS
radio are presented in Table C-23. Note, however, that the antennas used
vary widely.

**Table C-23**: Representative Technical Characteristics of MARS System
(1.7-30 MHz Band)

+-------+--------+-------+--------+---------+--------------------------+
| **Sys | **Ban  | *     | **Ant. | **Ant.  | **Modulations**          |
| tem** | dwidth | *Ant. | Height | Type/** |                          |
|       | (      | Gain  | (Ft)** |         |                          |
|       | kHz)** | (d    |        | **      |                          |
|       |        | Bi)** |        | Polariz |                          |
|       |        |       |        | ation** |                          |
+-------+--------+-------+--------+---------+--------------------------+
| MARS  | 2.7    | 0-10  | 0-80   | Dipole, | Amplitude modulated,     |
|       |        |       |        | yagi,   | Analog and digital,      |
|       |        |       |        | log     | single or multiple       |
|       |        |       |        | pe      | channels, suppressed     |
|       |        |       |        | riodic/ | carrier, telephony and   |
|       |        |       |        |         | telegraphy.              |
|       |        |       |        | H & V   |                          |
+-------+--------+-------+--------+---------+--------------------------+

**C.3 FEDERAL GOVERNMENT SPECIAL OPERATIONS**

**C.3.1 Automatic Link Establishment (ALE) Systems**

The Federal Government employs ALE subsystems in the medium to high
frequency (MF-HF) range of the radio spectrum to eliminate the need for
extensive training needed for manual establishment of HF and MF radio
channels that use ionospheric (skywave) signal propagation. An ALE
system is characterized by periodic polling of several frequencies
(typically seven or more) that are assigned to a station to determine if
ionospheric circuits are available at these frequencies. An ALE equipped
radio automatically selects the best channel for communications by
maintaining in real time a data base of link performance (*e.g.*,
received signal-to-noise power ratio) versus frequency for each
addressee in the users net and using that data to choose frequencies on
which to initiate a link. A network of stations is assigned a number of
frequencies over which to communicate, and each station is assigned a
unique address (*e.g.,* alpha-numeric).

For example, station A, attempting to establish a link with station B
will repetitively broadcast the address code for station B over one of
the assigned network frequencies. This transmission will last long
enough for station B to automatically scan its assigned frequencies. If
station B receives and recognized its address code, it stops on that
frequency. The equipment at both ends of the link will then
automatically handshake and alert the operators that the link has been
or can be established, and the desired traffic can be transmitted
(*e.g.*, voice, secure voice, and data). If communications fail, the ALE
equipment tries another frequency in the preset list until a link is
established or the operator is informed of communications failure.
Failures will occur, for example, if interference prevents
communications on frequency assignments that an ALE system would
otherwise determine to be the best available channels, in which the user
will not realize that interference is the cause.

**C.3.2 Sounders**

In general, sounders are used to gain an in-depth real-time knowledge of
the ionosphere conditions important to communication applications. In a
stable ionospheric condition, sounder data need only to be taken every
15 minutes, and a complete record can be obtained in a fraction of a
minute. Sounders data typically are used in support of non-ALE
applications.

There are three main types of sounding systems; namely, backscatter,
oblique and vertical incidence sounders. Backscatter sounders typically
receive weak signals originating from a signal transmitted to the
ionosphere, scattered back to the Earth's surface, back to the
ionosphere, and scattered back to the original transmitter site and its
associated receiver system. This technique is well suited for obtaining
the propagation conditions as they relate to range, azimuth bearing, and
frequency of operation. Oblique sounding uses an intermittent beacon
located at a known distance from the receiver site. Since the range
variable is removed, the resulting signal will be due to the ray-path
distance associated with the various layers in the ionosphere. With good
synchronization between the beacon and the receiver system, detailed
information can be readily obtained. With this method, it is possible to
determine the ionospheric virtual height. However, for this method to be
applicable, the beacon must be placed in the area under the portion of
the ionosphere that is of interest. Vertical incidence sounding provide
information regarding the portion of the ionosphere that is directly
overhead. The advantage of this type of sounding is that the transmitter
and the receiver are co-located and this greatly simplifies the
synchronization problem between the transmitter and the receiver.
Operationally, however, the vertical incidence sounders are the least
desirable type of sounder for determining appropriate communication
system parameters. Table C-24 provides a summary of the Federal
Government agencies sounding systems and relevant technical
characteristics.

**C.3.3 Over the Horizon (OTH) Radars**[^24]

Over the horizon radar systems are employed by the DOD. The OTH radars
use skywave propagation to detect targets at long ranges from the radar
transmitter site. The target return is a result of the backscatter
signal traversing the path to the ionosphere and back to the original
transmitter site (primary radar) or an alternative site (secondary
site). OTH radar systems generally utilize more bandwidth than is
typically used for communications. These systems place increased demands
on the amount of spectrum used and performance is greatly affected by
the characteristics of the ionospheric channel. OTH-HF radars are
capable of detecting targets at distances beyond the horizon and
therefore, targets located well beyond the range of the conventional
microwave radar. This increased range is possible due to the ability of
the HF signals to propagate well beyond the line-of-sight either by
ground wave diffraction around the curvature of the Earth or by skywave.
An example OTH radar system operating in the HF portion of the spectrum
is the AN/TPS-71. A brief description of this system is provided below.

**Table C-24: Federal Government Sounding Systems and Technical
Characteristics**

+---+-------+-------+------+-----+-----+-----+-------------------+
| * | *     | **No. | **Op | **  | *   | **G | **Function(s)**   |
| * | *Rece | of    | erat | Emi | *An | ain |                   |
| F | iver\ | Ass   | ing\ | ssi | ten | /** |                   |
| e | T     | ignme | Fr   | on\ | na\ |     |                   |
| d | ype** | nts** | eque | Ba  | Typ | *   |                   |
| e |       | [^25] | ncy\ | ndw | e** | *Po |                   |
| r |       |       | (kH  | idt |     | lar |                   |
| a |       |       | z)** | h** |     | iza |                   |
| l |       |       |      |     |     | tio |                   |
| A |       |       |      |     |     | n** |                   |
| g |       |       |      |     |     |     |                   |
| e |       |       |      |     |     |     |                   |
| n |       |       |      |     |     |     |                   |
| c |       |       |      |     |     |     |                   |
| y |       |       |      |     |     |     |                   |
| * |       |       |      |     |     |     |                   |
| * |       |       |      |     |     |     |                   |
+---+-------+-------+------+-----+-----+-----+-------------------+
| A | DIGI  | 2     | 415  | 20K | \-- | 1   | -Provides         |
| F | SONDE |       | -200 | M0N |     | 5/T | ionosphere data   |
|   | 128   |       | 12.5 |     |     |     | to AF Global      |
|   |       |       |      |     |     |     | Weather Center    |
+---+-------+-------+------+-----+-----+-----+-------------------+
|   | DPS-4 | 2     | 10   | 30K | \-- | 1   | -Ionospheric      |
|   |       |       | 00-4 | V7D |     | 0/T | research.         |
|   |       |       | 0000 |     |     |     |                   |
|   |       |       |      |     |     |     | -Propagation      |
|   |       |       |      |     |     |     | research          |
+---+-------+-------+------+-----+-----+-----+-------------------+
|   | DI    | 1     | 222  | 60K | \-  | 1   | -Regional         |
|   | GITAL |       | 0.5- | M1N | \-- |     | ionospheric       |
|   | IONO  |       | 2465 |     |     |     | forecast and      |
|   | SONDE |       |      |     |     |     | specification     |
+---+-------+-------+------+-----+-----+-----+-------------------+
|   | AN/F  | 20    | 1012 | 2H5 | Bro | 0-  | -Weather          |
|   | MQ-12 |       | .5-3 | N0N | ad- | 16/ | forecasting.      |
|   |       |       | 0000 |     |     |     |                   |
|   |       |       |      | 75K | b   | T/H | -Ionospheric      |
|   |       |       |      | M0N | and |     | research          |
|   |       |       |      |     | dip |     |                   |
|   |       |       |      | 75K | ole |     | -Provides         |
|   |       |       |      | P0N |     |     | ionospheric data  |
|   |       |       |      |     |     |     | to AF Global      |
|   |       |       |      | 6   |     |     | Weather Center    |
|   |       |       |      | 00H |     |     |                   |
|   |       |       |      | F9W |     |     |                   |
+---+-------+-------+------+-----+-----+-----+-------------------+
| A | AN/T  | 2     | 20   | 2H5 | Dou |     | -Support Army's   |
| R | RQ-35 |       | 00-3 | N0N | ble |     | fixed             |
|   |       |       | 0000 |     | De  |     | communications    |
|   |       |       |      |     | lta |     |                   |
+---+-------+-------+------+-----+-----+-----+-------------------+
| N | R-236 | 15    | 20   | 2H5 | Pha | 0-  | -Wide area        |
|   | 8/URR |       | 00-3 | N0N | sed | 36/ | surveillance.     |
|   |       |       | 0000 |     | arr |     |                   |
|   | AN/T  |       |      | 1   | ay/ | V&H | -Detection,       |
|   | PS-71 |       |      | 00H |     |     | location,         |
|   |       |       |      | N0N | Wh  |     | tracking of       |
|   | AN/AR |       |      |     | ip/ |     | aircraft and      |
|   | C-191 |       |      | 6   |     |     | ships.            |
|   |       |       |      | 00H | Log |     |                   |
|   |       |       |      | F1B | pe  |     | -Air Defense      |
|   |       |       |      |     | rio |     | warning.          |
|   |       |       |      | 4K2 | dic |     |                   |
|   |       |       |      | F3N |     |     |                   |
|   |       |       |      |     |     |     |                   |
|   |       |       |      | 4K2 |     |     |                   |
|   |       |       |      | Q1N |     |     |                   |
|   |       |       |      |     |     |     |                   |
|   |       |       |      | 1   |     |     |                   |
|   |       |       |      | 00K |     |     |                   |
|   |       |       |      | Q1N |     |     |                   |
|   |       |       |      |     |     |     |                   |
|   |       |       |      | 1   |     |     |                   |
|   |       |       |      | 00K |     |     |                   |
|   |       |       |      | F3N |     |     |                   |
+---+-------+-------+------+-----+-----+-----+-------------------+
| C | \-\-- | 1     | 10   | 40K | \-- |     | -Propagation      |
|   |       |       | 00-2 | P0N |     |     | research studies  |
|   |       |       | 0000 |     |     |     |                   |
+---+-------+-------+------+-----+-----+-----+-------------------+
| D | ST    | 5     | 25   | 1   | I   | 2   | -Doppler shift    |
| O | QIONO |       | 05-1 | 00H | nve |     | measurement to    |
| E | SONDE |       | 4990 | NON | rte |     | support DOE       |
|   |       |       |      |     | d-V |     | earthquake        |
|   |       |       |      |     |     |     | monitoring        |
|   |       |       |      |     |     |     | system.           |
+---+-------+-------+------+-----+-----+-----+-------------------+

**[AN/TPS-71.]{.underline}** The Navy's AN/TPS-71 is transportable OTH
radar, with an operating frequency range of 5-28 MHz that can provide
wide area active surveillance in support of tactical forces. Uses
include detection, location, and tracking of aircraft and ship targets
at a range of up to 1600 nautical miles in high interest marine areas.
Transportable, in this sense, refers to having the capability to
redeploy the system to another location over a period of time, as
opposed to tactical mobility. This provides the Navy flexibility to be
responsive to changing threat patterns and capabilities. This is a
frequency agile system. There are a few OTH radar sites in the United
States (AK, TX, and, two in VA), and few more overseas. The basic
technical characteristics of the AN/TPS-71 receiver are shown in Table
C-25.

**Table C-25: Technical Characteristics of the AN/TPS-71 System (1.7-30
MHz Band)**

+--------+--------+-------+--------+----------+-----------------------+
| **Sy   | **Ban  | *     | **Ant. | **Ant.   | **Modulations**       |
| stem** | dwidth | *Ant. | Height | Type/**  |                       |
|        | (      | Gain  | (Ft)** |          |                       |
|        | kHz)** | (d    |        | **Polari |                       |
|        |        | Bi)** |        | zation** |                       |
+--------+--------+-------+--------+----------+-----------------------+
| AN/    | 4      | 9-36  | Not    | Phased   | FM/CW or              |
| TPS-71 | .2-100 | ^\*^  | ava    | Array/   | Angle-modulated,      |
|        |        |       | ilable |          | single channel, with  |
|        |        |       |        | Vertical | analog or digital     |
|        |        |       |        |          | signals.              |
+--------+--------+-------+--------+----------+-----------------------+

^\*^ The 9 dBi and 36 dBi antenna gains are measured at the 5 MHz to 28
MHz, respectively.

**C.4 SPECIAL OPERATIONAL CONSIDERATIONS**

**C.4.1 Operational Requirements for Access to Several Frequency
Assignments within an**

**Allocation**

Ionospheric (skywave) signal propagation is frequency selective and
frequencies usable for communications between any two points changes
over time throughout the day. This is why several different segments of
the 1.7-30 MHz frequency range are allocated to each radio service
(*i.e.*, so that the service has full-time access to frequencies that
are usable throughout the day). This is an important factor in assessing
the operational impact of broadband interfering signals that typically
overlap an entire HF allocation for one or more services. In the event
local harmful interference occurs across an HF allocation, the
associated service will not be able to operate in that locale for
several hours during the day.

Even if only a portion of a given allocation is subjected to local
harmful interference, the local communications reliability is greatly
diminished for services that utilize multiple frequency assignments
within a band. This is because the choice among multiple assignments
allows the local radio operator (or ALE system) to avoid channels that
are laden with relatively high local noise power levels or are in use by
other radio systems.

**C.4.2 Federal Government use of Radio Frequencies Below 30 MHz for
Domestic Fixed\
Service**

Section 8.2.11 of the NTIA Manual provides restrictions on fixed service
use of frequencies below 30 MHz. To insure that, insofar as practicable,
sufficient high frequencies will be available for the operation of radio
circuits essential to the national security and defense and to conserve
frequencies below 30 MHz for services which cannot operate adequately
without them, only in following circumstances shall departments and
agencies of the Executive Branch of the Government use frequencies below
30 MHz for domestic fixed service within the conterminous United States:

> a\) When it is indispensable to do so, and on the condition that the
> characteristics of the stations continue to conform to those in the
> GMF, a land station may communicate, on a secondary basis, with fixed
> stations or other land stations in same category, using its assigned
> frequencies;
>
> b\) Where technical and operational requirements dictate, fixed
> stations may transmit to other fixed stations for the domestic haul or
> overseas traffic in transit, or destined for the United Sates. Such
> domestic radio haul shall be a segment of the overall overseas radio
> system;
>
> c\) When there is a need to provide instantaneous transmission of
> vital emergency, operational command and alerting traffic of such
> importance as to affect the immediate survival and defense of the
> nation;
>
> d\) When required for use in an emergency jeopardizing life, public
> safety, or important property under conditions calling for immediate
> communication where other means of communication do not exist or are
> temporarily disrupted or inadequate;
>
> e\) When there is a need to provide for a communications system manned
> by fully qualified operators who are military reservists or affiliates
> (e.g., MARS). Except in emergencies, frequency assignments in this
> category shall not be used as a means for passing traffic that in the
> absence of such assignments would require delivery by other means;
>
> f\) When other telecommunication facilities do not exists, are
> inadequate, or are impracticable of installation, and when the use of
> frequencies above 30 MHz is not practicable; and
>
> g\) In an emergency where it has not been feasible to make prior
> arrangements for alternate means of communications, it is permissible
> to operate temporarily on regularly assigned frequencies in a manner
> other than that specified in the terms of an existing assignment or on
> other appropriate frequencies under special circumstances such as an
> emergency must actually exist or imminently threaten emergency
> operations shall be discontinued as soon as substantially normal
> communications facilities are restored.

Also, Section 8.2.11 (2) and (3) of the Manual supplements or clarifies
the above mentioned restrictions with respect to the requests for the
authorization of frequencies below 30 MHz for new systems or in
circumstances where congestion in the radio spectrum would be increased
materially, and establishing adequate radio backup of wireline
facilities in advance for use during an emergency.

**C.4.3 Summary of the Emergency use of Federal Government HF
Frequencies for the\
SHARES Program**

The National Communications System (NCS) SHARES HF Radio Program is a
key element in the national telecommunications infrastructure using
presently authorized HF radio networks and cooperating federal agencies.
SHARES is a collection of existing federal agency controlled HF stations
that will interoperate to exchange national security emergency
preparedness (NSEP) traffic for any federal entity during a crisis or
emergency. Participating agencies agree to accept SHARES actual or
simulated emergency traffic, assuming responsibilities for delivery or
relay to the extent it does not interfere with their own agency mission.
The SHARES HF Program supports Executive Order 12472, 12656, and
NSDD-97.

Agencies providing frequencies for the NCS SHARES program must have a
US&P assignment in the GMF. Operations under these assignments are
limited to SHARES operation and tests. Participating agencies in the NCS
SHARES HF Radio Program are authorized to test the operating system
periodically provided the respective agency Frequency Assignment
Subcommittee Representatives are notified at least 30 days in advance.

**C.4.4 National Criteria Established Jointly by NTIA and FCC on the use
of Frequencies\
from Appendix 27 Allotment Plan**

In the HF band, there are special and certain related aeronautical
mobile requirements not fully conforming to the definition of the
aeronautical mobile (R) service that have to be satisfied by the
frequencies from ITU RR Appendix 27 allotment plan. However, the use of
these frequencies will abide within the limitations of the following
national criteria established jointly by the NTIA and FCC:

> 1\) Communications related to safety and regularity of flight between
> an aircraft and those aeronautical stations primarily concerned with
> flight along national or international civil air routes shall have
> absolute priority over all other uses;
>
> 2\) Use of (R) band high frequencies shall be limited to single
> sideband air/ground and incidental air/air communications beyond the
> range of VHF/UHF facilities;
>
> 3\) Users shall share frequencies to the maximum extent possible;
>
> 4\) Requirements shall be handled on a case-by-case basis;
>
> 5\) A showing must be made that the accommodation of the requirements
> in the bands other than aeronautical mobile (R), *e.g.*, fixed bands,
> is not satisfactory for technical, operational, or economic reasons;
>
> 6\) Only those requirements will be considered where the primary need
> for communications is for the safety of the aircraft and its
> passengers or for operational control communications, *i.e.*,
> "communications required or exercising authority over initiation,
> continuation, diversion, or termination of a flight in accordance with
> the provisions of Annex 6\" (ICAO);
>
> 7\) Use of aeronautical mobile (R) high frequencies in accordance with
> the foregoing normally shall be limited to non-military; and
>
> 8\) If the aforementioned criteria are met, the stipulation that (R)
> bands are to be used only for flights along national and international
> civil air routes need not be met.

[^1]: Grant, W.B., et al., *Spectrum Resource Assessment of Government
    Use of the HF (3-30 MHz) Band*, NTIA Technical Memorandum 89-141,
    June 1989. Relevant information from this study is included in this
    Appendix.

[^2]: Interference to encrypted radio channels can be particularly
    harmful insofar as considerable time is needed to reestablish
    communications in an encrypted mode of operation.

[^3]: http:/www.acd.itt.com/sincgars.htm.

[^4]: *Id.*

[^5]: http:/www.globalsecurity.org/military/systems/ground/sincgars.htm.

[^6]: *Supra* note 1 at 66.

[^7]: *Id.* at 69.

[^8]: http://webhome.idirect.com/\~jproc/hyperbolic/loran_c_future.html.

[^9]: *Frequencies for Distress and Safety Communications for the Global
    Maritime Distress and Safety System*, ITU Radio Regulations,
    Appendix S15, Geneva 1998.

[^10]: Broadcasting Board of Governors Response to NTIA Memo,
    *Questionnaire Regarding Equipment and Operations in the 1.7-80 MHz
    Frequency Range*, November 7, 2003.

[^11]: NTIA, *Manual of Regulations and Procedures for Federal Radio
    Frequency Managers,* U.S. Department of Commerce, National
    Telecommunications and Information Administration, Washington, D.C.,
    January 2004 Revision.

[^12]: *Id.* at 8-13.

[^13]: *Id.*

[^14]: *Id.* at 8-14.

[^15]: *Supra* note 1 at 72.

[^16]: http:/www.avionicswest.com/marker beacon receiver.htm.

[^17]: *Id.* at 6-11.

[^18]: 47 C.F.R. §2.1(c).

[^19]: *Id.*

[^20]: http://www.arrl.org/hamradio.html.

[^21]: http:/www.asc.army.mil/mars/mars/.

[^22]: http:/www.//afmars.tripod.com/mars1.html.

[^23]: *Supra* note 1 at 83-84.

[^24]: *Supra* note 1 at 74.

[^25]: In the Government Master File, an assignment may represent
    multiple radio equipments.