ADVANCED HF/VHF TACTICAL RADIO
Note. ALE HF radio systems procured by units are becoming more prevalent, as IHFRs such as AN/PRC-104, AN/GRC-192 and 213 are no longer in production. The ALE HF radio addressed in this section was recognized at publication time as being used in the field but not necessarily representative of all the ALE HF systems.
The AN/PRC-150 I radio, refer to Figure 3-1, provides units with state of the art HF radio capabilities in support of fast moving, wide area operations. HF signals travel longer distances over the ground than the VHF (SINCGARS) or UHF (EPLRS) signals do because they are less affected by factors such as terrain or vegetation. The AN/PRC-150 I and AN/VRC-104(V) 1 and (V) 3 vehicular radio systems, provide units with BLOS communications without having to rely on satellite availability on a crowded communications battlefield. The systems’ manpack and vehicular configurations ensure units have reliable communications while on the move, and allow for rapid transmission of data and imagery.
- The AN/PRC-150 I has the following characteristics and capabilities
- Frequencies range from 1.6–29.9999 megahertz (MHz) using skywave modulation with
selectable low, medium and high output power. It also operates from 20.0000–59.9999 MHz FM with a maximum output of 10.0 watts
- Can be configured in manpack, mobile and fixed station configurations.
- Embedded Type I multinational COMSEC allows secure voice and data communications between ground and aircraft.
- Able to interface with SINCGARS cryptographic ignition key (CIK) is embedded in the removable key pad. ␣ Advanced electronic counter-countermeasures (ECCM) serial-tone FH improves communications reliability in jamming environments.
- Supports FH in HF narrowband, wideband and list.
- Programmable system presets for “one-button”operation.
- Internal tuning unit matches a wide variety of whip, dipole, and long-wire antenna automatically.
- Includes an internal, high-speed MIL-STD-188-110B serial-tone modem, which provides data operation up to 9,600 bits per second (bps).
- Embedded MIL-STD-188-141A ALE, digital voice 600 that simplifies HF operation by quickly and automatically selecting an accepted channel. ␣
- Supports NATO Standardization Agreement (STANAG) 4538 automatic radio control system link set-up and data link protocols in 3G ALE radio mode.
- Supports networking capabilities using point-to-point protocol or Ethernet.
- Supports wireless Internet Protocol (IP) data transfer when operating in STANAG 4538 (3G).
The transceiver’s extended frequency range (1.6–60 MHz) in combination with 16 kbps digital voice and data enables fixed frequency interoperability with other VHF FM CNRs. It provides Type 1 voice and data encryption compatible with advanced narrowband digital voice terminal (ANDVT)/KY-99, ANDVT/KY-100, VINSON/KY-57, and KG-84C cryptographic devices.
The AN/PRC-150 I is also capable of data communications by utilizing the TacChat software that is provided with the radio. Point-to-point data transmission can be completely secure and, with the use of the radios, 3G ALE synchronized scanning can be initiated quickly and smoothly.
MIXED EXCITATION LINEAR PREDICTION
Mixed excitation linear prediction (MELP) implemented in the AN/PRC-150 I can operate at both 600 and 2400 bps data rates. MELP has the ability to provide a significant increase in secure voice availability over degraded channels particularly at the 600 bps data rate when compared to other digital and analog forms of voice modulation.
The MELP speech mode uses an integrated noise pre-processor that reduces the effect of background noise and compensates for poor response at the lower speech frequencies. By using digital voice techniques such as band-pass filtering, pulse-dispersion filters, adaptive-spectral enhancement and adaptive noise pre- processing, voice communications performance over channels with low signal to noise (S/N) ratios typical of the urban combat environment can now be made useable and reliable.
The MELP capability is comparable to lowering the frequency, using higher power, and improving antenna efficiency which translates into decibels (dB) of “processing gain” and a better capability to communicate over urban terrain. In effect MELP is compensating for path loss and antenna inefficiency.
Last ditch voice (LDV) mode is designed to work when nothing else will. LDV takes advantage of digital voice processing at a much lower data rate (75 bps) in order to slash digital errors caused by marginal conditions. LDV is not a “real time” transmission mode but LDV has both a broadcast and an automatic-request for wireless network extension capability.
Voice data packets are created and sent in the transmitting radio. The radio then sends the packets at a very slow data rate using sophisticated error detection and correction digital coding techniques. Data packets are stored in the receiving radio and checked for errors in transmission caused by poor transmission path characteristics.
In an automatic request for wireless network extension mode corrupted packets can be returned to the transmitting radio in the event too many packets have too many errors for decoding into useable voice communications.
In broadcast mode all packets are stored upon receipt the first time. Radio software then assembles the packets and cues the RTO. The Soldier at the receiving radio then plays the message like a voicemail. The lower data rate and extensive signal processing can produce impressive performance since LDV can recover signals from below the noise levels. This can be equated to a considerable increase (3 dB or double) in transmitter power.
- Falcon II Manpack Radio
- Applications Handbook