SINCGARS

From HFUnderground

Military tactical radio - FM tactical radio system Single Channel Air-Ground Radio System, commonly known as SINCGARS "sink-gars", FM or Fox Mike radio. SINCGARS and FM are used in conjunction with HF-SSB systems, UHF/SHF/EHF SATCOM and other communications systems for tactical military communications purposes. See also: militia radio frequencies and militia intra-squad radio (ISR) frequency list militia patriot tactical short-range UHF ISR UISR UHFISR frequencies.

VHF Tactical FM Land Mobile Air-Ground Military Communications

Two Harris RT-1523 SINCGARS ASIP radios with ECCM capability for anti-jam and secure voice and data for tactical military communications, shown in use by the US military

Two handheld VHF-FM tactical radios Datron HH7700 30-88 MHz (30.000 MHz to 87.975 MHz or 30.0000 MHz to 87.9875 MHz) in 25 kHz steps, with no frequency hopping capability, the radio below is a vehicle-mounted VHF-FM military tactical radio. The HH7700 radio has the capability to switch to narrowband 12.5 kHz steps, doubling the number of available channels from 2320 channels to 4640 channels

VHF-FM tactical radio system, with frequency-hopping and voice encryption/data encryption capabilities. Operating in the 30.000 to 87.975 MHz frequency band with 25 kHz channel steps. Uses 150.0 Hz CTCSS squelch system. Operates in single-channel (SC) and frequency-hopping (FH) modes for voice and data. Original generation SINCGARS radio such as the RT-1439 VRC set (VRC-87 configuration) and modern radios such as the Harris RT-1523 series offer +/5 kHz and +/- 10 kHz offset frequencies from the standard 25 kHz channels.

Single channel mode, also known as fixed frequency, is referred to as VULOS, or VHF UHF Line Of Sight (LOS). It is a catch-all term for VHF-FM 30-88 MHz, VHF-AM 108-150 MHz, VHF-FM 136-174 MHz, UHF-AM 225-399.975 MHz and UHF-FM 380-512 MHz fixed frequency clear (plaintext, or PT) or encrypted (ciphertext, or CT) simplex communications nets, including low power UHF 380-430 MHz intra-squad tactical radios (low power, very short range - also called "Personal Role Radio" or PRR).. Duplex or half-duplex repeaters (relay, retrans) or retransmission facilities may be used for VULOS nets. Frequencies in the 30.000 to 87.975 MHz range may be used for these nets in conjunction with SINCGARS, UHF SATCOM and UHF aircraft HAVE QUICK ECCM nets. PRC-148, PRC-152 and similar radios make reference to the VULOS radio net type. See also: PRC-150 HF/VHF radio (1.5-30 MHz SSB and various digital modes, 30-60 MHz [59.999 MHz] FM only. FM radios often have a "deviation" (bandwidth) setting. SINCGARS and fixed channel mode is generally set to 8 kHz deviation (36 kHz bandwidth) at 25 kHz steps. Land mobile settings include 5 kHz deviation (20 kHz bandwidth) and 2.5 kHz deviation (10 kHz bandwidth, regular narrow FM).

Most radios include relay capability (called RETRANS or retransmit in military usage). It is important to note the difference between RELAY and REPEATER operation (modern military VHF FM tactical radios are capable of both). Relay operation involves two radios and two sets of TX/RX frequencies. Repeater operation involves semi-duplex (different TX and RX frequencies) operation that most amateur radio operators are familiar with.

For example:

• Relay Operation:

• Channel 1 - TX and RX 30.150 MHz - mountaintop or other elevated position - connected to Channel 2 radio
• Channel 2 - TX and RX 49.850 MHz - mountaintop or other elevated position - connected to Channel 1 radio

Signals received on 30.150 MHz are retransmitted on 49.850 MHz and signals received on 49.850 MHz are retransmitted on 30.150 MHz. So squad A would set their radios to transmit and receive on 30.150 MHz and squad B would set their radios to transmit and receive on 49.850 MHz. No split or offset frequencies involved, the end users operate their radios in regular single frequency simplex mode.

• Repeater Operation:

• Channel 1 - TX 32.375 MHz - mountaintop or other elevated position
• Channel 1 - RX 41.700 MHz - mountaintop or other elevated position

All users would set their radios to transmit on 41.700 MHz and receive on 32.375 MHz (split frequency operation, half-duplex) mode. Signals transmitted on 41.700 MHz are repeated on 32.375 MHz. Signals transmitted on 32.375 MHz are not retransmitted on 41.700 MHz. This is the traditional repeater operation most folks are familiar with. Installing radio sets with even modest transmit power levels and simple 1/4 wave or ground plane antennas on mountaintops can provide excellent coverage for low power tactical VHF FM sets.

Compatible with previous-generation FM radios such as the PRC-25, PRC-77, PRC-1077, HH7700 and dozens of other similar tactical handheld, manpack and vehicle-mounted radios operating in the 30-76 MHz (30.00 to 75.95 MHz in the original PRC-25/PRC-77 and VRC-12 channeling) or 30-88 MHz range. NATO military forces and many other military forces use similar frequencies for tactical purposes, almost always with FM voice. The US military fields radios that operate in the 30-174 MHz and 30-512 MHz ranges to support SINCGARS, regular VHF-FM, 136-174 MHz VHF-high band services like VHF marine, aircraft radios, SATCOM and interoperability with other radio systems that use VHF/UHF.

However, certain bands in the 30-50 MHz range (VHF low band) are allocated to exclusive government/military use. There are non-military government users of these frequencies, however most federal government agencies have moved to the 162-174 MHz and/or 406-420 MHz federal bands with the proliferation of trunking systems.

Background and History

SINCGARS evolved from basic simplex and duplex military systems operating in the low to mid VHF range (30.00 to 75.95 MHz) starting with the revolutionary PRC-25 radio. The PRC-25 (and associated VRC-12 vehicle radio set) utilized 150.0 Hz CTCSS squelch combined with indent channelization for frequency control vs. manual tuning with a VFO greatly simplified radio operation. The CTCSS system removed the need for adjustable squelch and made it easy for the average solider to use a radio with minimal training. The PRC-25 and PRC-77 (and dozens of clones, improvements, etc.) are considered hallmarks of battlefield communications simplicity and function. Their origin lies in WWII with the adoption of the SCR-300 (BC-1000) backpack (manpack) radio developed and manufactured by Motorola.

The US military pioneered the use of FM voice on the battlefield in World War II with the original "three band" system, allocating 20 to 27.9 MHz to armor (100 kHz steps), 27 to 38.9 MHz to artillary (100 kHz steps) and 38 to 54.9 MHz to infantry (100 kHz steps). The famous BC-1000 or SCR-300 backpack radio fielded in WWII operated in the 40 to 48 MHz range using 200 kHz steps and FM voice (falling within the 38-55 MHz "infantry band". Tank radios with FM provided vast improvement over AM-based systems on the battlefield. While the SCR-300 / BC-1000 did use a VFO, it featured channels labelled on the display instead of frequency and included a fine-tuning/adjustment signal generating function for battlefield fine tuning. Its use did require adjustment of the squelch and fine-tuning (meaning that the operator still needed to be trained in its use, compare to the PRC-25/PRC-77/VRC-12 family of radios, that are "soldier-proof"). With the adoption of the PRC-25/VRC-12 radios the "three band" system was abandoned, allowing cross-unit communications without the need for multiple radios. It also provided considerably more available channels (30-76 MHz in 50 kHz steps - 920 available channels vs. 20-55 MHz in 100 kHz steps - 350 available channels). Use of HF SSB and CW systems continued throughout the Vietnam war and up to the present day for long range communications and special operations uses.

The SCR-300 and similar high-HF/low-VHF radios developed in WWII and the Korean War revolutionized small unit tactics. First the capability for a platoon or similar level unit to communicate with its headquarters or commanding elements and then the capability for each man in a squad for fireteam to communicate with each other in addition to the longer-range communications capability for platoon-to-commander and platoon-to-platoon communications using FM radio have changed the battlespace forever. The SCR-300 radio provided 0.3 watts (300mw) power output, which provided anywhere from 2-5 miles of range, depending on which antennas were being used. The SCR-508 and SCR-608 family of FM tank radios featured significantly higher transmit power and more effective antennas, greatly improving range. While the SCR-300/BC-1000 radio operated FM voice in the 40-48 MHz range (200 kHz channel steps, FM voice, fully channelized - 40.000 MHz = channel 0, 40.200 MHz = channel 1, 47.800 MHz = channel 39, 48.000 MHz = channel 40, etc.). Only channel numbers were shown on the display.

Tank and mobile radios (for example, the SCR-508 series, SCR-608 series, SCR-510, SCR-610, etc.) were crystal controlled and used 100 kHz channel steps. On the BC-604 transmitter, the crystal for channel 0 (20.000 MHz) was labeled "channel 0 - 20.0 MC", the crystal for channel 50 was labeled "channel 50 - 25.0 MC", 27.000 MHz would be "channel 70", 27.9 MHz would be channel 79 and so on. This continued up through the 27.000 MHz to 38.900 MHz band and the 38.000 MHz to 54.900 MHz band.

The German military made extensive use of the high-HF/low-VHF "boundary area" at 30.0 MHz for mobile communications, including manpack radios, portable radios, tank radios, panzer command and control radios, air-to-ground radio and air-to-air communications. German equipment utilized AM voice and often had the capability for MCW (tone transmission). The standard German tank radio was the 10W.S.c transmitter combined with the Ukw. E. e (Ultrakurzwellen Empfänger e) receiver covering 27.2 MHz to 33.3 MHz (some sources say 27.2 MHz to 33.4 MHz or even 27.0 MHz to 33.4 MHz) in 50 kHz channel steps. This equipment (transmitter and receiver) was referred to as the FuG 16 (FuG being a shortening of funkgerat, or "radio equipment"). The transmitter was rated for 10 watts (it is unclear if that figure is AM PEP power, AM carrier power or AM average power. British testing of the equipment indicates a lower power output (6-7 watts). Later on, a higher power (20 watt transmit power rating) version became available. Additional equipment used by the Germans include the 20 watt 20W.S.b transmitter (25.0 MHz to 27.1 MHz coverage in 50 kHz steps), the 20W.S.c. transmitter (27.2 MHz to 33.3 MHz coverage) and the 20W.S.d. transmitters (42.1 MHz to 47.8 MHz coverage).

Just like the American FM sets operating in the same frequency range, frequencies were given channel designations. For example, 27.500 MHz would be shown as 275 on the display. 27.600 MHz would be the next number on the frequency display, with a line between the 100 kHz marks. So to tune to 27.850 MHz, the operator would simply tune his radio to the line halfway between 27.800 MHz and 27.900 MHz.

German radio equipment operating on slightly different bands (for example, 23.0 MHz to 24.95 MHz for field artillery units) and various subsets of the 40 MHz band were also extensively used. The higher frequencies were used for air-to-ground liaison purposes, i.e. close air support communications. Various incarnations of equipment operating in the 42.100 MHz to 47.800 MHz MHz range were used for this purpose. The Luftwaffe also utilized the VHF band for air-to-air communications, 38.500 MHz to 42.300 MHz (note the overlap).

Portable tactical radios included the Kleinfunksprecher d , KlFuSpr.d (Dorette), operating between 32.000 MHz and 38.000 MHz in 100 kHz channel steps, AM voice and 0.2 watt (200mw) transmit power output. Other portable walkie-talkie radios include the Feldfu.f AM portable operating in the 27.800 to 33.200 MHz band (listed as 28.000 MHz to 33.000 MHz in the specifications). Like the 32-38 MHz transceivers, it used 100 kHz channel steps and was used for short-range tactical communications. The Torn. Fu. d2 was a transportable VHF transceiver covering the 33.800 MHz to 38.000 MHz band with a transmitter output power of 1 watt. With base station antennas (basically the German version of the RC-291 and RC-292 series vertical ground plane antennas) this radio could provide impressive range for battlefield tactical purposes and communications with other similar radios as well as smaller tactical VHF AM radio sets.

The basic military backpack radio (and now handheld radio) concept has been copied endlessly, to the point where even militias and guerrilla forces use similar VHF/UHF radios for similar purposes. For example, see Ukraine militia forces using Baofengs (UV-5R, UV-82 and similar VHF/UHF handheld Chinese radios) and fighters in Afghanistan using Icom IC-V8s and other 2 meter / VHF handheld radios for battlefield tactical purposes, often in conjunction with 26-28 MHz CB type equipment or other similar radios/bands.

Communist Bloc countries, including the Soviet Union (and former Soviet Union, now Russia), Poland, as well as Western and Central European military forces also use similar frequency ranges (for example, 26 MHz - 70 MHz or 26 MHz - 71 MHz is/was a popular frequency split for tactical radios, instead of 30-76 MHz). Various handheld and manpack radios covering these bands have been manufactured and used in various countries.

Captured radios from Iraq in the first and second Gulf Wars (Iraq Wars) indicate the 30-76 MHz (in 25 kHz steps, FM mode) band was used heavily by the Iraqi Army for tactical communications. The Iraqi military apparently used Italian made manpack and vehicle radios, as well as Soviet/Russian radios in the same frequency band.

The PRC-638 manpack (backpack portable or transportable) radio made by IRET in Italy covers 30.000 MHz to 79.975 MHz in 25 kHz steps, with selector switches for 30 MHz/40 MHz/50 MHz/60 MHz/70 MHz, rotary decade switches for 0-9 and then a selector for 00 kHz, 25 kHz, 50 kHz or 75 kHz. For example, to select the frequency 31.575 MHz, the user would select "3", "1", "5" and then "75" on the radio's panel.

This is very similar in operation to the PRC-25/PRC-77 and VRC-12 (RT-542/VRC, RT-246/VRC, RT-246A/VRC, aux receiver R-442/VRC R-442A/VRC) series of radios. However, on many of the Eastern style radios, there are knobs for each digit, vs. having a knob for MC steps (1 MHz steps) and a knob for KC change (kHz steps, 00, 25, 50 or 75 or 00/50 depending on channel steps). In the example above, a FM radio would have four knobs, the first changing between the 30 MHz, 40 MHz, 50 MHz, 60 MHz, or 70 MHz band, the second changing between 0 and 9, the third changing between 0 and 9 and the last switching between 00, 25, 50 and 75. To select 51.00 MHz, the user would switch the first knob to the "5" position, the second knob to the "1" position, the third knob to the "0" position and the last knob to the "00" position (to show the frequency readout of 51.000 or 51000. In theory, being able to go up/down 10 MHz steps, 1 MHz steps and 100 kHz steps provides the capability for faster frequency changes (frequency agility). In real battlefield conditions, however, the utility of this is debatable at best.

Other radios use the same concept - but instead of allowing the operator to select the frequency directly, the switches select a channel number. An example of this would be the RU-2 manpack portable VHF FM radio, which covers 30.000 MHz to 69.950 MHz in 50 kHz steps. The channel selection is made using three selector knobs, A, B and C - which correspond to the 3 digit channel number. Knob A has 8 positions, 0, 1, 3, 4, 5, 6 and 7. Knob B and knob C have 10 positions, the digits 0 through 9. This allows the selection of channel numbers 000 through 799. Channel 000 is 30.000 MHz, channel 001 is 30.050 MHz, channel 002 is 30.100 MHz, channel 003 is 30.150 MHz, up to channel 798 being 69.900 MHz and 799 being 69.950 MHz. The end result is effectively identical, and the operator is provided with a conversion chart to quickly convert the 3-digit channel number to a frequency in MHz.

Evolution of military radio tactical radio bands

Evolution of military FM radio tactical radio bands World War II, Korea and Beginning of Vietnam War (roughly 1940-1960)

Most of Vietnam War and Cold War (roughly 1960s-1980s) - although older-generation HF tactical radios and FM radios continued to be used.

1980s-present (starting in the 2000s and 2010s radios such as CB radios, amateur radios, and other COTS equipment has become more prevalent on the battlefield)

Federal Government and Military Only Bands 30-50 MHz

This list applies to the United States only. The US military will often use frequencies outside these bands (but within the 30 MHz - 88 MHz VHF SINCGARS FM band) on a non-interference basis.

NTIA Federal and Non-Federal Allocations

For additional information, see the legal users of the 25-30 MHz 11 meter / 10 meter spectrum and the Business Radio (Business Band) land mobile radio service page - including the VHF low band subsection.

• 30.000 MHz - 30.560 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate air-to-ground and air-to-air communication systems in this band for tactical and training operations. The federal agencies operate land mobile radio communication systems in this band to support natural resource management and wildlife telemetry.

• 30.560 MHz - 32.000 MHz - Non-Federal and Federal - FIXED, LAND MOBILE - The military agencies operate communication systems in this band for tactical and training operations. The federal agencies operate land mobile radio communication systems in this band to support natural resource management and forest fire fighting. Inter-operable communications are used to support mutual aid response with local public safety agencies. 30.56 MHz to 31.98 MHz (20 kHz steps), allocated for state government (forestry) and business/industrial land mobile services.

• 32.000 MHz - 33.000 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate radio communication systems in this band for networks providing command and control for combat, combat support, and combat service support for tactical and training operations. They also operate tactical air-to-ground and air-to-air communication systems for close air support missions. The federal agencies operate land mobile radio communications systems in this band to support land management and to protect natural resources.

• 33.000 MHz - 34.000 MHz - Non-Federal and Federal - FIXED, LAND MOBILE - The federal agencies operate land mobile radio communication systems in this band to support mutual aid response with local public safety agencies. The military agencies operate communication systems in this band for tactical and training operations. They also operate tactical air-to-ground and air-to-air communications systems for close air support missions. 33.02 MHz to 33.98 MHz (20 kHz steps), allocated for local government (33 MHz fire radio band) and some limited business/industrial land mobile services (33.34 MHz, 33.4 MHz, etc.).

• 34.000 MHz - 35.000 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate radio communication systems in this band for networks providing command and control for combat, combat support, and combat service support as part of tactical and training operations. They also operate tactical air-to-ground and air-to-air communication systems for close air support. The federal agencies operate land mobile radio communication systems in this band to support law enforcement and facilities security management, natural resource management, park security law enforcement at national parks, forests, and wildlife refuge areas.

• 35.000 MHz - 36.000 MHz - Non-Federal and Federal - FIXED, LAND MOBILE - 35.02 MHz to 35.98 MHz land mobile business and industrial radio systems, local paging systems. The military agencies operate communication systems in this band on a non-interference basis for tactical and training operations.

• 36.000 MHz - 37.000 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate radio communication systems in this band for networks providing command and control for combat, combat support, and combat service support as part of tactical and training operations. They also operate tactical air-to-ground and air-to-air communication systems in this band for military close air support missions. The federal agencies operate land mobile radio communication systems in this band to support national park management, law enforcement, public safety nets, contingencies, and natural resources management.

• 37.000 MHz - 37.500 MHz - Non-Federal and Federal - LAND MOBILE - 37.02 MHz to 37.5 MHz (20 kHz channel steps) public safety, law enforcement, and business/industrial land mobile systems. The military agencies operate radio communication systems for tactical and training operations on a non- interference basis.

• 37.500 MHz - 38.000 MHz - Non-Federal and Federal - LAND MOBILE, RADIO ASTRONOMY - The National Science Foundation uses this band to perform radio astronomy research into continuum observations to study electromagnetic radiation from the planet Jupiter and from the Sun.

• 38.000 MHz - 38.250 MHz - Federal - FIXED, MOBILE, RADIO ASTRONOMY - The military agencies operate radio communication systems in this band for networks providing command and control for combat, combat support, and combat service support as part of tactical and training operations. They also operate tactical air-to-ground and air-to-air communication systems for close air support missions. The Coast Guard operates ship-to-ship and ship-to-shore communication systems in this band. The National Science Foundation uses this band to perform radio astronomy research into continuum observations to study electromagnetic radiation from the planet Jupiter and from the Sun.

• 38.250 MHz - 39.000 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate communication systems for combat net radio operations to provide command and control for combat, combat support, and combat service support as part of tactical and training operations. They also operate tactical air-to-ground and air-to-air communication systems for close air support missions. The federal agencies operate land mobile radio communication systems for the operation, protection, and maintenance of national parks, forests, wildlife refuge areas, and to support law enforcement, public safety operations, control of power generation transmission and water facilities, environmental data collection, fish management, and wildlife telemetry programs.

• 39.000 MHz - 40.000 MHz - Non-Federal and Federal - LAND MOBILE - 39.02 MHz to 39.98 MHz (20 kHz channel steps) used for local and state police communications, interoperability and other emergency services. Federal agencies operate land mobile radio communications systems to support public safety responses to local communities. The military agencies operate radio communication systems in this band for networks providing command and control for combat, combat support, and combat service support for tactical and training operations. They also operate tactical air-to-ground and air-to-air communication systems for close air support missions.

• 40.000 MHz - 42.000 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate radio communication systems in this band for networks providing command and control for combat, combat support, and combat service support as part of tactical and training operations. They also operate tactical air-to-ground and air-to-air communication systems for close air support missions. The federal agencies operate land mobile radio communication systems used in the operation, protection, and maintenance of national parks, forests, wildlife refuge areas, and to support public safety operations, environmental data collection, fish management, and wildlife telemetry programs. The federal agencies operate meteor-burst communications systems in this band to provide beyond line-of-sight communications and telemetry. A typical application is the Department of Agriculture transmitting snow fall data from numerous sensors to a central location - the SNOTEL telemetry system on 40.67 MHz.

• 42.000 MHz - 43.690 MHz - Non-Federal and Federal - FIXED, LAND MOBILE - 42.00 MHz to 42.94 MHz (20 kHz channel steps) state police radio systems (supplanted or replaced by VHF high band, UHF or 700 MHz/800 MHz digital trunking systems in many states). Business and industrial land mobile systems operate between 42.96 MHz and 43.68 MHz. The military agencies operate radio communication systems for tactical and training operations on a non- interference basis.

• 43.690 MHz - 46.600 MHz - Non-Federal and Federal - FIXED, LAND MOBILE - 43.70 MHz to 46.58 MHz (20 kHz channel steps) public safety, law enforcement, and business/industrial land mobile systems. The military agencies operate radio communication systems for tactical and training operations on a non- interference basis.

• 46.600 MHz - 47.000 MHz - Federal - FIXED, LAND MOBILE - The military agencies operate radio communication systems in this band for combat net radio operations to provide command and control for combat, combat support, and combat service support as part of tactical and training operations. They also operate tactical air-to-ground and air-to-air radio communication systems for close air support missions. The federal agencies operate land mobile radio communication systems in this band for contingency response to various national disasters, national resources management, law enforcement, tornado tracking, and various meteorological research programs.

• 47.000 MHz - 49.600 MHz - Non-Federal and Federal - LAND MOBILE - 47.02 MHz to 49.58 MHz (20 kHz channel steps) public safety, law enforcement, and business/industrial land mobile systems. The military agencies operate radio communication systems for tactical and training operations on a non- interference basis. The National Aeronautics and Space Administration (NASA) use this band to research and observe wind shear conditions for spacecraft

• 49.600 MHz - 50.000 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate radio communication systems in this band for combat net radio operations to provide command and control for combat, combat support, and combat service support as part of tactical and training operations. They also operate tactical air-to-ground and air-to-air radio communication systems for close air support missions. The federal agencies operate land mobile radio communication systems in this band for contingency response to various national disasters, national resources management, law enforcement, tornado tracking, and various meteorological research programs.

• 50.000 MHz - 54.000 MHz - Non-Federal and Federal - AMATEUR - 6 meter amateur radio band. The military agencies operate radio communication systems for tactical and training operations in this band on a non-interference basis.

• 54.000 MHz - 72.000 MHz - Non-Federal and Federal - BROADCASTING. The military agencies operate radio communication systems for tactical and training operations in this band on a non-interference basis.

• 72.000 MHz - 73.000 MHz - Non-Federal and Federal - FIXED, MOBILE - The military agencies operate radio communication systems for tactical and training operations in this band on a non-interference basis. 72.02 MHz - 72.98 MHz is an operational fixed band for business, industrial users. This band is also shared with the 72 MHz RC frequencies (72.01 MHz to 75.99 MHz).

• 73.000 MHz - 74.600 MHz - Federal - RADIO ASTRONOMY, FIXED, MOBILE - The National Science Foundation uses this band to perform radio astronomy research via continuum observations to identify characteristics of stars, planets, and gases such as their elemental composition, temperature, etc. The military agencies operate radio communication systems for tactical and training operations in this band on a non-interference basis.

• 74.600 MHz - 74.800 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies operate land mobile radio communication systems used by military aircraft crews. The federal agencies operate portable-to-portable communication and low-power communication systems that are used inside power plant facilities to remotely control devices. The military agencies operate radio communication systems for tactical and training operations in this band on a non-interference basis.

• 74.800 MHz - 75.200 MHz - Federal - AERONAUTICAL RADIONAVIGATION - The Federal Aviation Administration operates Instrument Landing System (ILS) marker beacons in this band to provide navigational guidance information during aircraft approach and landing on 75.0 MHz. 74.8 - 75.2 MHz guard band.

• 75.200 MHz - 75.400 MHz - Federal - FIXED, MOBILE, LAND MOBILE - The military agencies use this band for fixed and mobile radio communications. Typical uses are runway light control systems and communication to aircrews. The federal agencies use this band for land mobile radio communications for public safety operations, low power operations to the remote control of mechanical devices, and other uses.

• 75.400 MHz - 76.000 MHz - Non-Federal and Federal - FIXED, MOBILE - The military agencies operate radio communication systems for tactical and training operations in this band on a non-interference basis. 75.4 MHz - 75.98 MHz is an operational fixed band for business, industrial users. This band is also shared with the 75 MHz RC frequencies (75.41 MHz to 75.99 MHz).

• 76.000 MHz - 88.000 MHz - Non-Federal and Federal - BROADCASTING. The military agencies operate radio communication systems for tactical and training operations in this band on a non-interference basis.

Commonly used VHF low VHF mid and HF high bands HF/VHF bands

Other common variations on the VHF low band/VHF mid band coverage for FM tactical radios include:

• 26.000 MHz - 69.950 MHz SEM-25 / SEM-35 and similar clones/variants used in Europe and elsewhere (26-70 MHz)
• 26.000 MHz - 71.950 MHz PRC-25/PRC-77 variants used in dozens of different countries (often listed as 26-71 MHz or 26-72 MHz)
• 28.000 MHz - 73.950 MHz PRC-25/PRC-77 variants used in dozens of different countries (often listed as 28-73 MHz or 28-74 MHz)
• 26.000 MHz - 71.950 MHz PRC-25-T PRC-25 variant developed by TADIRAN (Israel) for Greece. Greek military band 50 kHz steps
• 46.000 MHz - 57.975 MHz SEM-52 and similar radios, often listed as 46-58 MHz - 25 kHz channel steps
• 26.000 MHz - 70.000 MHz Radio Set 3600 - Dutch origin, used in various countries - RT-3600
• 30.000 MHz - 75.975 MHz VRC-4622 - Dutch successor to Radio Set 3600 / RT-3600 - 25 kHz channel steps
• 26.000 MHz - 70.000 MHz TRC-552 - French origin, used in Africa, etc. as well 25 kHz or 50 kHz channel steps depending on version
• 26.000 MHz - 76.000 MHz TRC-552 - variant with matching coverage for use with TRC-571
• 26.000 MHz - 76.000 MHz TRC-571 - French origin, used in Africa, etc. as well 25 kHz or 50 kHz channel steps depending on version
• 47.000 MHz - 56.950 MHz Radio Set 3610 - Dutch origin, used in various countries
• 30.000 MHz - 107.975 MHz Radio Set SPIDER - Dutch origin, used in various countries
• 53.000 MHz - 75.000 MHz PRC-614 handheld tactical radio (similar to PRC-68 series, 30.000 MHz - 79.975 MHz or 30.000 - 87.975 MHz)
• 36.000 MHz - 75.975 MHz Racal TRA-967 and various clones
• 47.000 MHz - 54.400 MHz CPRC-26 100mw-300mw FM, 6 crystal controlled channels, very short range
• 36.000 MHz - 60.000 MHz Station Radio C42 15-20 watt FM mobile/vehicle radio, 50 kHz steps
• 23.000 MHz - 38.000 MHz Station Radio C45 15-20 watt FM mobile/vehicle radio, 50 kHz steps
• 47.000 MHz - 54.400 MHz Station Radio A40 100mw-300mw FM, backpack, 6 XTAL channels, very short range
• 38.000 MHz - 55.000 MHz Station Radio A41 0.75 watt 750mw FM manpack radio, 50 kHz or 100 kHz channel steps depending on version
• 26.300 MHz - 38.000 MHz Station Radio A42 0.75 watt 750mw FM manpack radio, 50 kHz or 100 kHz channel steps depending on version
• 38.000 MHz - 56.000 MHz Station Radio B47 0.5 watt 500mw FM manpack or vehicle radio, 100 kHz channel steps
• 26.000 MHz - 38.000 MHz Station Radio B48 0.5 watt 500mw FM manpack or vehicle radio, 100 kHz channel steps
• 37.000 MHz - 47.000 MHz PRC-349 Clansman portable radio
• 36.000 MHz - 57.000 MHz PRC-350 Clansman portable radio
• 30.000 MHz - 76.000 MHz VRM-5080 and various versions, 25 kHz steps with datalink, encryption mode, secure voice and frequency hopping
• 26.000 MHz - 71.950 MHz RV-3 or TR-PP-13B 50 kHz channel steps, 26.00 MHz - 48.95 MHz low band/49.00 MHz - 71.95 MHz high band (designed for export)
• 34.100 MHz - 41.700 MHz Ra120 Swedish manpack portable VHF FM tactical radio, 100 kHz steps
• 39.600 MHz - 48.000 MHz Ra121 Swedish vehicle VHF FM tactical radio 100 kHz steps
• 39.600 MHz - 48.000 MHz Ra121B Swedish manpack version of the RA121 VHF tactical radio
• 47.000 MHz - 57.000 MHz Ra122 Swedish manpack portable VHF FM tactical radio, 100 kHz steps
• 40.000 MHz - 48.000 MHz RUP-2 / RUP-2B Yugoslavian and Eastern European clone of SCR-300 / BC-1000 backpack radio
• 30.000 MHz - 79.975 MHz SEM-70 and similar clones/variants used in Europe and elsewhere
• 30.000 MHz - 79.975 MHz SEM-80 / SEM-90 and various clones/copies - 25 kHz steps (European version of the PRC-25/PRC-77/VRC-12 family)
• 30.000 MHz - 79.975 MHz numerous Russian, Chinese and similar clones/copies
• 21.500 MHz - 28.500 MHz R-109D / R-109M Russian manpack radio 1 watt FM
• 28.000 MHz - 36.500 MHz R-108D / R-108M Russian manpakc radio 1 watt FM
• 36.000 MHz - 46.100 MHz R-105D / R-105M Russian manpack radio 1 watt FM
• 41.000 MHz - 46.850 MHz R-106 Russian portable manpack radio, 150 kHz steps, AM voice
• 48.500 MHz - 41.500 MHz R-126 Russian manpack radio, short-range tactical 0.3 watt FM
• 44.000 MHz - 51.800 MHz R-147 Russian portable manpack radio, very short range, 125mw FM, 100 kHz channel steps
• 37.000 MHz - 51.950 MHz R-148 Russian manpack radio, 1 watt power, 50 kHz steps, FM platoon/company tactical radio (similar to PRC-25)
• 44.000 MHz - 50.000 MHz R-352 Russian portable radio, 0.8 watt, 3 crystal controlled channels - 300 kHz steps FM
• 44.000 MHz - 50.000 MHz R-392 Russian portable radio, 1 watt, 6 crystal controlled channels FM
• 30.000 MHz - 79.975 MHz R-158 (Russian/Soviet manpack radio) and various clones/copies (25 kHz steps, offset versions to 79.9875 MHz)
• 20.000 MHz - 51.500 MHz R-123 Russian tank radio (20.00 MHz - 35.75 MHz low band, 35.75 MHz - 51.50 MHz high band)
• 20.000 MHz - 22.375 MHz R-113 Russian tank radio 25 kHz steps, FM voice
• 20.000 MHz - 49.975 MHz Type 889 radio - numerous Chinese and similar clones/copies (used in tanks, armored vehicles, etc.)
• 20.000 MHz - 49.975 MHz Often found in export-type vehicles and radio systems used in Africa, Middle East, etc.
• 27.000 MHz - 32.000 MHz Older-generation Russian (Soviet) manpack radios (FM voice) cf. 27.000 MHz - 38.900 MHz old PRC-9/PRC-9A bands
• 30.000 MHz - 80.000 MHz PRC-80, made in Israel, exported worldwide
• 47.000 MHz - 56.900 MHz PRC-239 designed in Italy - 100 kHz steps, exported to Middle East, etc.
• 40.000 MHz - 49.975 MHz PRC-439 designed in Italy - 25 kHz steps, exported to Middle East, etc.
• 30.000 MHz - 79.975 MHz PRC-638 designed in Italy - 25 kHz steps, used by Iraq and various other countries
• 30.000 MHz - 88.000 MHz Scimitar V - 25 kHz steps - FM voice or data, available with or without frequency hopping
• 66.000 MHz - 88.000 MHz Scimitar M - 25 kHz steps - FM voice or data, available with or without frequency hopping
• 68.000 MHz - 87.975 MHz Scimitar M Variant with slightly different frequency coverage for export use
• 30.000 MHz - 50.000 MHz A-53 portable manpack radio from South Africa
• 26.000 MHz - 77.000 MHz B-56 portable manpack radio/fixed radio from South Africa
• 30.000 MHz - 87.875 MHz HH7700, PRC-7700 and numerous other handheld and manpack radios cover this band
• 30.000 MHz - 87.9875 MHz Similar radios listed above, but with 12.5 kHz steps available, offset frequencies (narrowband)
• 27.500 MHz - 39.500 MHz Asian fishery radio systems, FM mode 25 kHz channels 27.5 MHz - 39.475 MHz FT-801 and clones
• 33.000 MHz - 49.000 MHz Various COTS Chinese VHF low band radios cover this band
• 43.300 MHz - 43.600 MHz 43 MHz Italy band radios - unmodified versions cover 43.3000 MHz - 43.5875 MHz in 12.5 kHz steps
• 42.300 MHz - 45.100 MHz modified 43 MHz equipment, 12.5 kHz steps to 45.0875 MHz - widely used in Eastern Europe, Ukraine and elsewhere
• 29.700 MHz - 36.000 MHz Various COTS VHF low band radios cover this band - see also 27-36 MHz, 29-36 MHz
• 36.000 MHz - 42.000 MHz Various COTS VHF low band radios cover this band
• 36.000 MHz - 59.000 MHz Various COTS VHF low band radios cover this band (for example, Alinco DJ-V17L, 36-58.995 MHz)
• 40.000 MHz - 60.000 MHz Various COTS VHF low band radios cover this band (for example, Alinco DR-135LH)
• 29.000 MHz - 49.975 MHz Various COTS VHF low band radios cover this band
• 42.000 MHz - 50.000 MHz Various COTS VHF low band radios cover this band
• 29.000 MHz - 37.000 MHz Various COTS VHF low band radios cover this band
• 30.930 MHz - 31.370 MHz Various COTS VHF low band radios - Nordic hunting radio - JAKTRADIO 31 MHz
• 35.000 MHz - 50.000 MHz Various COTS VHF low band radios cover this band
• 35.000 MHz - 48.500 MHz Various COTS VHF low band radios cover this band - see Soontone ST-45 handheld radio 35-48.5 MHz 5 watt
• 37.000 MHz - 48.000 MHz Various COTS VHF low band radios cover this band - Vertex FTL-2011 and similar (similar bands available)
• 37.000 MHz - 50.000 MHz Various COTS VHF low band radios cover this band
• 28.000 MHz - 40.000 MHz Various COTS VHF low band radios cover this band
• 66.000 MHz - 88.000 MHz Various COTS VHF mid band radios cover this band (for example, AnyTone AT-588HF 70 MHz/4 meter version)
• 25.615 MHz - 30.105 MHz Modern standard export radio 10 meter radio frequency coverage (25.610 MHz - 30.110 MHz) see Anytone AT-5555, AT-6666, Superstar 9900, CRE 8900, etc.
• 25.615 MHz - 28.305 MHz Export CB 11 meter 10 meter radio band 240 channel 6 band plan coverage (Superstar 3900 etc)
• 26.515 MHz - 27.855 MHz Export CB 11 meter 10 meter radio band 120 channel 3 band low mid high band plan coverage
• 26.515 MHz - 27.99125 MHz Export CB radio European UK band plan (see also: 26.510 MHz - 27.860 MHz, 26.565 MHz - 27.99125 MHz, 26.510 MHz - 27.995 MHz)
• 25.165 MHz - 28.755 MHz Export CB 11 meter 10 meter radio band 320 channel 8 band plan coverage see Galaxy DX 99, DX 99V2, etc.
• 26.065 MHz - 29.655 MHz Export CB 11 meter 10 meter radio band 320 channel 8 band plan coverage (modified)
• 24.265 MHz - 29.655 MHz Export CB 11 meter 10 meter radio band 480 channel 12 band plan coverage
• 26.065 MHz - 28.755 MHz Export CB 11 meter 10 meter radio band 240 channel 6 band plan coverage (modified)
• 25.615 MHz - 31.005 MHz Export CB 11 meter 10 meter radio band 480 channel 12 band plan coverage (modified)
• 25.615 MHz - 29.695 MHz Export CB 11 meter 10 meter radio band Magnum 257HP, etc (25.610 MHz - 29.700 MHz)
• 26.065 MHz - 30.555 MHz Export CB 11 meter 10 meter radio band 400 channel 10 band plan coverage
• 26.510 MHz - 27.860 MHz Export CB Russian CB band (see also: 26.515 MHz - 27.865 MHz)
• 25.615 MHz - 27.995 MHz Export CB Russian export band (see also, 25.610 MHz - 27.995 MHz)
• 26.000 MHz - 32.000 MHz Export CB band (cf. RCI-2950, RCI-2970 series of radios)
• 24.500 MHz - 30.000 MHz Export CB band, various 12m/10m radios

As discussed in previous paragraphs, there is a move to COTS equipment, including non-standard radios such as amateur radios, VHF marine band radios, CB/11 meter radios and other land mobile radios in the VHF/UHF band for tactical purposes. Unfortunately, VHF low and VHF mid band does not work well in heavily built up areas (i.e. urban warfare radios). High band VHF and UHF work considerably better in these environments. It is because of this that the modern PRC-148 and PRC-152 radios cover 30-512 MHz instead of just 30-76 MHz or 30-88 MHz. Chinese clones of Russian or Soviet combat net / tactical radios, including tank radios and manpack portable and mobile radios cover similar frequency ranges as well. 20-60 MHz, 20-50 MHz, 30-80 MHz and others are common. 30.000 MHz to 79.975 MHz is another commonly available band, using the 25 kHz channel steps. Western equipment generally favors 30.000 MHz to 87.975 MHz.

Easily acquired and widely available commercial off-the-shelf (COTS) communications equipment has introduced additional bands (as a replacement to or in conjunction with, or as a replacement for, the standard military bands as emerging threats in areas where asymmetric warfare, guerrilla warfare and insurgency tactics are used. The military make extensive use of HF, other VHF/UHF systems including dedicated VHF (118-150 MHz) and UHF (225-400 MHz) aircraft systems, UHF (380-430 MHz) intra-squad or inter squad radio systems, datalink systems operating in the 2-30 MHz HF band, the 225-400 MHz UHF band, the 960-1215 MHz UHF band and specialized battlefield remote sensing systems such as REMBASS (138-153 MHz, channelized as 138.025 MHz is channel 1, 138.050 MHz is channel 2 up to 152.975 MHz is channel 593 - 25 kHz channel steps, data links with repeater networks incorporated).

Improvements with radio technology allowed for all three bands to be combined and moved from 20-55 MHz to 30-76 MHz and eventually 30-88 MHz, reducing channel spacing from 100 kHz to 50 kHz (Vietnam War) to 25 kHz (SINCGARS and present day). With the addition of frequency-hopping (ECCM - electronic counter-counter measures or anti-jam) and voice encryption (COMSEC) the FM radio became the standard battlefield tactical radio for ground and air communications. In the United States, most military systems still use 50 kHz step compatible frequencies for range control (cf. Fort Hood Range Control on 30.450 MHz is often heard during 11m/CB/10m and VHF low band band openings). See the frequency bands above. The 30 MHz, 32 MHz, 34 MHz, 36 MHz, 38 MHz, 40 MHz, 41 MHz and 46/47 MHz bands are very popular for CONUS-based military communications.

Military Radio Communications Bands Generally

Military radio comms frequencies run the entire radio frequency (RF) spectrum. VLF and ELF are used for communications with submarines. Medium frequency (mediumwave) through HF (shortwave) is used for long-haul data and voice communications. HF is still extensively used for tactical communications worldwide. Most militaries consider "HF" to be 2-30 MHz or 1.6 MHz to 29.9999 MHz or so, even though that includes a decent chunk of the 300 kHz to 3 MHz MF band. Most DXers consider military users to be a subsection of the utility stations (or "ute") stations.

Military users tend to make extensive use of the HF aircraft bands, the HF marine bands (maritime mobile bands), the fixed/mobile allocations, unused sections of the shortwave broadcasting bands and, in many cases, the amateur radio bands/ham radio bands. Use of automatic link establishment or ALE is commonplace.

Most analog HF military SSB voice comms will be in USB mode, although use of AM, AME (J3E emission - USB with carrier re-inserted), narrow band FM (or "narrow band phase modulation") and LSB also takes place. Morse code (CW) is still widely used, for communications and as part of radio beacon systems, channel markers and/or other stations with classified purposes such as the famous "Buzzer" UVB-76, etc. Use of various digital modes, including digital voice, standardized digital/data modes, data modes, RTTY, which the US military calls RATT - both single frequency and frequency hopping - is quite extensive.

Most military HF comms appear to be the unused portions of the HF aircraft bands, quiet portions of the fixed/mobile allocations and others. Some radios include HF and VHF, or portions thereof. Examples include 1.6 MHz to 60 MHz AM/FM/CW/SSB/data (FM only available above 20 or 30 MHz).

• VHF and up - military radios (VULOS)
• 30-88 MHz FM - de facto standard tactical FM radio. Some countries use a variant of this (for example, 30-79.975 MHz, 30-80 MHz, 26-70 MHz, 30-108 MHz, etc.). 25 kHz steps, some use of 12.5 kHz steps
• 30-174 MHz AM/FM/data - multi-standard radios - allows use of the regular FM tactical band, plus higher frequencies and access to LMR/PLMR land mobile services, VHF marine band, etc.
• 30-512 MHz AM/FM/data - see 30-174 MHz, with the addition of the 225-400 MHz UHF aircraft band, UHF SATCOM, and the UHF 400 MHz/500 MHz land mobile bands (see COTS radios, ISR, etc.)
• 108-150 MHz AM - aircraft comms (VHF), including the regular civilian 118-137 MHz band and the military 137-144 MHz and 148-150.8 MHz portions.
• 136-174 MHz - tactical comms, FM voice, NFM voice, various digital voice modes such as DMR, P25, and so on. Use of encryption is extensive.
• 136-174 MHz - Operation with existing civilian LMR systems, VHF marine band, amateur radio 2 meter band, MURS, business band and civilian walkie-talkies (see: Baofeng)
• 225-400 MHz AM - UHF aircraft band, 25 kHz steps. Use of frequency hopping and encryption extensive. Band is also used for tactical data links.
• 230-290 MHz FM - UHF or "UHF" SATCOM bands, wide (25 kHz steps) and narrow (5 kHz steps). Shared with the UHF aircraft band and used for other services in some areas.
• 225-512 MHz AM, FM and digital modes - squad radio, wideband networking radio, SATCOM and UHF aircraft band all in one
• 380-400 MHz - Statewide LMR systems, P25 trunking. 380 MHz - 389.9875 MHz repeater output, 390 MHz - 399.9875 MHz repeater input. Also used for simplex inter squad radio ISR.
• 380-430 MHz - Inter squad radio and similar uses - short range tactical radio (FM voice, digital voice, usually using handheld radios, including COTS radios like Baofengs - UV-82, UV-82HP, UV-5R, etc.)
• 403-470 MHz - Standard UHF non-tactical radios (land mobile radios - LMR/PMR), see also: civilian bands and services such as PMR446, LPD433, the FRS and GMRS frequencies and similar services
• 400-470 MHz - Short range squad radio, inter squad radio, inter-squad radio, etc. Examples include basic 16 channel handheld Baofeng, Icom, Kenwood, Vertex, Motorola radios to higher-end digital voice with encryption
• 400-512 MHz - Inter squad radio and similar uses - short range tactical radio (FM voice, digital voice, usually using handheld radios, including COTS radios like Baofengs - UV-82, UV-82HP, UV-5R, etc.)
• 902-928 MHz - So-called "ISM" band radios, short range comms within a squad, fireteam, etc. Frequency hopping spread spectrum [FHSS] used extensively. Similar to the PRR except operating on 900 MHz instead of 2.4 GHz
• 960-1215 MHz - Tactical data links (TADIL), many other data uses (cf. Link-11, Link-16, Link-22)
• UHF and up - various data links, point-to-point fixed links, 700 MHz to 1000 MHz, frequency hopping squad radio or personal tac radios - see also: Personal Role Radio.
• UHF/SHF - data links, tactical data links, UAV (drone) control links, etc. Overlaps with the license-free bands (900 MHz, 2.4 GHz, and so on). SATCOM systems have mostly migrated from UHF only to UHF/SHF/EHF or just SHF/EHF.

• COTS - Civilian Radios VHF/UHF radios
• 25-30 MHz - 11 meter band (CB radio) 25.615 MHz to 28.305 MHz, 25.615 MHz to 30.105 MHz or the legal 26.965 MHz to 27.405 MHz band. AM, FM and SSB modes are all popular.
• 136-174 MHz - Very common coverage for commercial off the shelf civilian radios, including the Icom VHF handhelds (IC-V8, IC-V82, etc.) popular with insurgent groups to the Baofeng, etc. VHF, UHF or VHF/UHF radios
• 400-520 MHz - Very common coverage for commercial off the shelf civilian radios, including the Baofeng UV-82, UV-5R and so on.

Amateur Radio Operators Using Surplus Military Equipment

Because previous-generation, vintage or antique military radios with 30-76 MHz or 30-88 MHz frequency bands cover the 6 meter amateur band, and WWII and Korean War vintage equipment covers 20-28 MHz or 20-27.9 MHz and 27-38.9 MHz or 27-39 MHz amateur radio operators will often use surplus equipment in the 10 meter and 6 meter bands for FM communications. Vintage military radio equipment is also used by amateur operators in the HF bands and VHF bands above 6 meters where available. This includes the 4 meter band around 70 MHz, which is available in select countries for amateur use. The PRC-8/PRC-8A (20 MHz-28 MHz), PRC-9/PRC-9A (27 MHz-39 MHz), PRC-10/PRC-10A (38 MHz-55 MHz), PRC-25, PRC-77 and similar radios are very popular with amateur or ham radio operators who keep these vintage radios alive by operating them on the amateur bands.

51.0 MHz is the most common military amateur radio frequency on 6 meters, as this allows for compatability with 100 kHz channel steps, 50 kHz channel steps, 25 kHz channel steps and tunable radios such as the PRC-10 or PRC-10A. Before the adoption of the PRC-25 and VRC-12 family of radios, armor (tanks), artillery and infantry each had their own radio bands (20-28 MHz for armor/tanks, 27-39 MHz for artillery and 38-55 MHz [or some subset thereof] for infantry). For example, the famous walkie-talkie backpack or manpack radio SCR-300 (BC-1000) covered 40-48 MHz in 100 kHz steps while the PRC-6 "banana radio" handheld transceiver or HT covered 47-55.4 MHz. The VRC-8/VRC-9/VRC-10 radios operate wide deviation FM (60K0F3E emission, 15 kHz deviation). 65 kHz wide receive bandwidth.

With the adoption of the PRC-25 and VRC-12 family of radios (and associated fixed and aircraft radios), armor, artillery and infantry could all communicate using the same radios, greatly improving tactical battlefield communications in time for the Vietnam War.

• PRC-6 - 47.00 MHz to 55.40 MHz (crystal controlled, single channel)
• PRC-8 and PRC-8A - 20.00 MHz to 27.90 MHz (100 kHz steps, continuous tuning)
• PRC-9 and PRC-9A - 27.00 MHz to 38.90 MHz (100 kHz steps, continuous tuning)
• PRC-10 and PRC-10A - 38.00 MHz to 54.90 MHz (100 kHz steps, continuous tuning)
• PRC-25 30.00 MHz to 75.95 MHz (50 kHz steps, channelized) - 150 Hz tone squelch
• PRC-77 30.00 MHz to 75.95 MHz (50 kHz steps, channelized) - 150 Hz tone squelch
• VRC-12 30.00 MHz to 75.95 MHz (50 kHz steps, channelized) - 150 Hz tone squelch or carrier squelch
• VRC-8 20.00 MHz to 27.90 MHz (100 kHz steps, continuous tuning) - RT-66 FM transceiver
• VRC-9 27.00 MHz to 38.90 MHz (100 kHz steps, continuous tuning) - RT-67 FM transceiver
• VRC-10 39.00 MHz to 54.90 MHz (100 kHz steps, continuous tuning) - RT-68 FM transceiver

Further Reading and Additional Resources

Radio Nerds - for a large library of resources on military radio gear, including technical and operations manuals.

N6CC's excellent military radio ham radio page - very extensive information on a well put together website, recommended reading - by N6CC - Navy 6 Combat Comms.

Navy-Radio.com - another extensive library of US Navy communications equipment from the 1950s and 1960s, with information on radios from the 1930s through the 1970s/1980s. VHF, UHF, MF and HF communications systems including ship-based, shore-based, short-range tactical radios, etc.