Page 33 - NAVAL FORCES 03/2017

C5I

communications for the US Navy (USN) four channel AN/USC-61 Dig-
ital Modular Radios (DMR). DMR work across the entire 2 megahertz
(MHz) – 2 gigahertz (GHz) band, thus covering not only HF but also
VHF, UHF and some SATCOM channels (excluding SATCOM channels
such as X-, Ku- and Ka-bands are further up the spectrum beyond UHF).
The radios are also equipped with General Dynamics Advanced Infosec
Machine (AIM) encryption chip to carry classified information at Type
1 – Top Secret level and below. Moreover, the USN also worked with the
US Army regarding the activation of the Mobile User Objective System
(MUOS) satellite communications network. This allows DMR radios to
complete voice calls and data transmission to and from the DMR to a
US Army AN/PRC-155 two-channel Manpack radio. MUOS have now
become mainstream in the USN, with Lockheed Martin announcing in
April 2017 that its fifth MUOS (MUOS-5) is now delivering secure,
beyond-line-of-sight communications to troops with legacy Ultra High
Frequency (UHF) radios.

The future of HF
Compared to HF radios a few decades back, a significant amount
of progress has already been made to address some of the key issues
with the technology. For instance, the vast majority of navies today are
equipped with HF radios with second-generation automatic link estab-
lishment (2G ALE), and increasingly new HF radios are being built with
3G ALE, such as all the radios presented in this article. ALE enables ra-
dio operators automatically to choose the best HF frequencies on which
two stations or a network of stations can transmit and receive. In other
words, where before an HF operator had to be able to scan for adequate
HF frequencies depending on ionospheric conditions, today the ALE
does it instead.
However, the realm of possible improvements ahead remains vast, es-
pecially in terms of technologies to allow for larger data transmission
through HF’s limited bandwidth. As noted by Mr Krotoff, Thales is work-
ing to facilitate the transmission of 100kbps of data through its MSN
8200: “this is already a significant technological advantage, because if
we want to increase the bandwidth further it will be necessary to adapt
the amplifier, which is really complicated technologically speaking”.
As HF remains the most cost efficient radio communication system,
and as countries with vast maritime territories and/or territories where
SATCOM coverage maybe lacking or when SATCOM may experience
jamming, these improvements to HF mean the road ahead is paved with
opportunities. NAFO

Leonardo’s HF 2000, offers navies the possibility to choose across
up to 64 channels per frequency pool.
NAVAL FORCES III/2017