RadioBanter - View Single Post

September 24th 03, 10:42 PM

In article ,
(Brian) writes:

Poor DICK. I'm sure the failure rate was quite high. Why the big
rush to RTTY and other modes which don't require the operator to be a
human modem?

Perhaps Len could shed some light on this.

I could, but it is like trying to teach pigs to fly...it annoys the pig and
the instructor. Nonetheless, I clean off the whiteboard and explain:

In the 1950s-1960s, morse code skills were taught to FIELD RADIO
MOS school students...but at (then named) Camp Gordon (now Fort
Gordon, GA). "Field" radios in the US Army then ranged from the old
WW2-era AN/GRC-9 two-man-pack portable to the AN/GRC-26 truck-
mounted hut containing an HF-range AM/CW/RTTY station (BC-610
transmitter) and having the masts and wires for a small rhombic.

"Angry-twentysixes" were deployed in Korea during the active war
period there (1950-1953) but the overwhelming mode of choice for field
communications was RTTY, not morse. The GRC-26 could transmit
RTTY and voice simultaneously. NVIS had not become a standard
acronym yet. Despite the hilly topology of Korean landscape, VHF
radio relay sets had become the "favorite" (most-used) method of radio
communication of any kind there. Such VHF radio relay carried voice
and TTY circuits, again the TTY preferred over manual morse code.

In the next decade, moving to southeast asia, the AN/TRC-24 (among
several) was the most used radio relay equipment, again carrying voice
and TTY. The '24 was easily spotted by the curious square antenna
configuration that worked from 40 to 400 MHz and could integrate with
Spiral-4 land cable having up to four in-line repeater amplifiers along
that cable. An integrated solution to networking at higher command
levels.

In the 1950s in Korea, the small-unit radio most used at first was the
BC-1000 "Walkie-Talkie" designed by Motorola in WW2. The AN/PRC-6
HT was next for easy squad use, on VHF and with the built-in facility for
active repeater operations. About 1952 late, the "three-band PRC-9"
family of manpacks replaced the SCR-300/BC-1000s, having less than
half the weight. Those extended into vehicle-mounted versions of the
manpack and were initially planned as three overlapping bands in VHF
intended for Artillery-Infantry-Armor units, each of those having a band.
All of the "9s" family had provisions for unattended repeater operation.

For Vietnam, Laos, and Cambodia all of the mentioned VOICE radios
were used plus the appearance of the almost-all-solid-state PRC-25
multi-channel synthesized portable VHF FM set (only the final amplifier
was a tube stage). By 1970 or so, the AN/PRC-77 appeared which was
essentially the same architecture but having all solid-state circuitry.
An eighth of a million models of the '25 and '77 were produced during a
decade and a half of production in several countries.

The original SCR-300/BC-1000 "walkie-talkie" was licensed for manufacture
in many countries, including the UK (there known as WS-11?). The
improved "9s" of the late Korean War vintage were also licensed out to
other countries. Motorola's Chicago works was the pioneer in the design,
beginning before WW2 (original "handie-talkie") and into the architecture
of the 1950s-introduced manpacks.

US military aviation pioneered the UHF "military aircraft band" of 225-
400 MHz beginning in the 1950s, notably the Collins Radio design which
was channelized and had AM voice...some were still on inventory as of
1970. The SINGLE CHANNEL SSB (single user) was pioneered again
by Collins Radio for the Strategic Air Command in the 1950s, the
ignition point for the adoption of single-user SSB by radio amateurs.

While several HF range portable and transportable communications
transceivers were in use from 1950 through 1990, all with carrier on-off
control and having manual telegraph keys as part of their system, the
modes of actual use were still voice. Carrier on-off control was largely
restricted to semi-remote site operation from a wire-linked control point
(some protection of personnel from enemy DFing and bombing of RF
emitters). Various forms of voice encryption and data machine coupling
appeared then.

The first of the SINCGARS family of VHF small-unit communications sets
appeared in 1989. Design was led by ITT Fort Wayne, IN, and allowed both
frequency-hopping and external encryption devices to defeat enemy
interception. That series continues in production today with the manpack
version reduced to half the bulk and weight and including internal
encryption
circuitry for both voice and data. A standard US military land and air set
for manpack, vehicular, or airborne use, a quarter million has been produced
by ITT and the former General Dynamics Land Division in Florida.

Army land communications includes a large number of different radio relay
sets (troposcatter included in my definition of that) and whole voice-data
telephone exchanges, all mobile and truck mounted, deployable anywhere
and capable of supplying all the needs of military communications at any
level from Corps on down. The Signal Center at Fort Gordon is now the
main Signal School for the US Army and other branches. Fort Monmouth
is now the home of the Electronics Command, USA, and is a center for
coordinating manufacturing and research in Army military communications.

The Military Intelligence Center at Fort Huachuca, AZ, has the only "code
school" left (morse code cognition) and that Center trains ALL branch
members and necessary government employees on various Military
Intelligence tasks. Morse code cognition is taught using commercial
morse code computer programs. Such cognition schooling is only a PART
of the overall M.I. electronic intelligence intercept task. A much larger
activity there is the UAV (Unmanned Aerial Vehicle) training.

The old mythology of "special forces behind enemy lines reporting back
intel via CW" has never surfaced in any history since the 1960s. During
the first Gulf War, the "behind the lines" radios were basically the
AN/PSC-2 which is low UHF, has three antenna choices (the
largest is a satellite "umbrella") and was designed to handle voice and
data, data to 1200 BPS using a small "chiclet" style keyboard. The
deployable AN/PSC-5 is now operational with more improvements. USAF
"Joint Stars" command aircraft can easily relay PSC radio comm to other
sites and the directional UHF antennas defeat most field DF operations.

In the US military, HF radio use is largely considered to be just a backup
mode of communications. The primary medium for communications is
land radio relay, satellete relay, and small unit radio netting at VHF and
higher. At fixed bases, land communications is connected to the DSN
which is considered as the "government's own Internet" that handles
voice and data digitally and includes encryption for both (if authorized).

There is NO morse code mode used for any tactical radio communications
anywhere in today's military. There is no evidence that strategic comm
(such as by Special Forces, SEALS, etc) uses any morse code modes;
their known equipment characteristics concern only voice and data modes.

It's not possible to tell/explain what happens in "code classes" when
there are none today...

Leonard H. Anderson