The 60's saw newer equipment and methodology being introduced into the fleet starting with the Mackenzie class.
When this class of ship came into service, there was a radical change in the layout of compartments. Gone, were the old Message Centre, Radio 1 and Radio 3. In place of these, the RCN designated a Communications Control Room (CCR) which occupied the same area and included the majority of equipment that used to be spread over several compartments. The CCR was designed to simplify message handling and control of radio equipment. No longer did the chief radioman have to send a man to a specific compartment to tune a transmitter. With the exception of some low frequency transmitters, all radio sets were close at hand in the CCR Personnel could work side by side with a minimum of wasted movement.
The introduction and use of SSB voice communications was a technical innovation for the navy and there were very sound technical reasons for wanting to do this. The principles of SSB were known as early as 1915 when SSB was first used on landline "carrier" equipment for frequency-division multiplexing of up to four telephone circuits on one wire pair.
In 1928, the very first radio trial of SSB began on VLF but the problem was one of getting adequate vacuum tube
power amplification. A four voice-channel SSB HF link was established between the Netherlands and the Netherlands Antilles in 1934 which proved it could be done and remain in service 24/7. Up to around 1950 there had been little work done on single-channel SSB for any radio service due to frequency stability problems however developments such as highly stable variable oscillators and the Collins mechanical filter made SSB not only practical but economical thus opening up this new mode.
The reasons for wanting to shift from AM to SSB are listed below:
A fully modulated AM signal has two thirds of its power in the carrier and only one third in both of the sidebands. In AM, the carrier is used to deliver the audio intelligence to the detector of the receiver and is then discarded. Each of the two side bands carry an identical copy of the audio intelligence. Why not suppress the carrier and one sideband ? This is precisely what is done in SSB transmission. Here are the advantages to be realized: * Heterodynes are eliminated at the receiver as no carrier is being transmitted.
* Since only one side band is being transmitted, the signal only takes up one half of the spectrum space occupied
by an equivalent AM signal.
* Since only one side band needs to amplified in the transmitter, the final amplifier can be made to run more
* Studies have shown that is possible to achieve gains of up to 9 decibels over AM.
* SSB is more readable than AM under more adverse receiving conditions.Other innovations which followed, were improved UHF communication systems that included a common antenna and multicoupler; a broadband MF/HF common transmitting antenna and coupler system; facsimile recorders and lastly, VHF FM transceivers for communication with merchant vessels.
This was a low power VHF/FM transceiver made by Pye Electronics in the UK. Consisting of one transmitter and two receivers, it provided line of sight ship-to-ship or ship-to-shore communications for harbour, docking or pilot service. It could also be used to monitor Channel 16 international distress frequency on Channel 16. Twenty eight channels are available with 50 KHz spacing.
Frequency Range: Transmitter - 156.05 to 157.40 MHz
|AN/SRT 502 Transmitter
The AN/SRT 502 was designed primarily for ship-to-shore or ship-to-ship communications. Included in the set, were two HF transmitters (3 to 28 MHz) for long distance work and one low frequency unit (100 to 550 kHz) for shorter distances. All three transmitters shared a common power supply. Modes of operation were CW, R/T and RATT, however, the LF transmitter was not designed for R/T operation and it also ran at a lower power level than its HF counterpart.
The high frequency transmitter was capable of producing a power input
of 1000 watts in high power operation, or 300 watts in low power mode.
Internally, the HF amplifier employed two 4-400A tubes in parallel, while
the LF amplifier employed a pair of 4-125 tubes. Any two transmitters could
be operated at the same time with high power input or alternatively, all
three transmitters could be operated in low power mode. (RCN photo taken
aboard HMCS Restigouche while in Halifax Harbour around 1960/61. Manning
the controls is ex-LSRM2 David Blais 36684-H )
Per BRCN 213,, the following crystals were available for use with the AN?SRT-502.
|AN/URC 32 Transceiver
This SSB transceiver was the first of its type to be installed in the fleet
and superseded the Marconi CM11. It was primarily designed for single sideband
transmission and reception on upper sideband, lower sideband or two independent
sidebands with separate audio and IF channels for each side band in the
range of 2 to 30 MHz. Other modes of operation included AM, CW, or FSK.
The equipment provided its own accurate and stable frequency control in
addition to external frequency control. Pictured above is the standard
URC-32 set as depicted in the RCN Trade Group 1 manual. Here is a summary
of the URC 32 operating and power modes. (RCN photo)
Tom Brent of Abbotsford, BC has studied the radio fittings in Mackenzie class ships and offers some insight on URC-32 variants. "When I got on board HMCS Mackenzie, Yukon, and Saskatchewan in the 1990's, the AN/URC-32 setup was different from what is depicted in the URC-32 photo above. Qu'Appelle was based on the East coast but a manual indicates the URC-32 radio fit was identical to the other three ships in the class.
While there were URC-32's in CCR (Command and Control Room) , they were of the OA-5079/URC-32 variant which is essentially the standard URC-32 less the RF Amplifier section. When transmitting, the low level output from these OA-5079/URC-32's was fed down two decks into the ship's transmitter room where there were five AN/SRA-502 amplifiers. These broadband "no tune" amps had a rating of 1000 watts PEP or 700 watts with a steady CW signal) and used sixteen 4CX250B's. The amplifiers were Remotely controlled by using the Panel Indicator SB-5053A/SRA-502A which was mounted at the top of URC-32 rack in place of the standard RF amplifier section. It provided indication of SWR and power output and allowed the operator to control input (AC) power, operate/standby switching and reset the AN/SRA-502 in the event of an overload.
The RF output from the SRA-502 amplifiers was fed into CU-714/SRA-22 antenna couplers which could match longwire antennas or a 35 foot whip. These SRA-22's were also controlled from the URC-32 rack by way of coupler control C-2698/SRA-22. In the URC-32 photo, it is the rack near the top with the three meters.
A general purpose AM receiver (Racal RA17) with a tuning range of 980 Kcs to 30 Mcs. It could be tuned down to 500 kcs, but the performance of the receiver was degraded in this range. It was the successor to the CSR5A receiver. (RCN Photo)
This was basically a URR501 receiver fitted with a low frequency RF converter (CV5046) to extend the frequency coverage down to 12 kHz. It was the successor to the RAK receiver. (RCN Photo)
The use of the SRR series receiver by the RCN is confirmed by a photo taken in HMCS Bonaventure's CCR. There, it was part of a RATT bay. Pictured is an example of the SRR-11 (Photo by Tom Brent)
Tom Brent provides a description of the SRR receiver series. "This receiver is a member of the AN/SRR-11/12/13 family of receivers designed by RCA for the US Navy in the early 1950's. These sets covered 14-600 kHz (SRR-11), 0.25 - 8.0 mHz (SRR-12) and 2.0 - 32.0 mHz (SRR-13). The one shown in the photo must be the AN/SRR-12 or AN/SRR-13 since the AN/SRR-11 has less knobs. I have both the '11 and '13 in my shack; the SRR-12 however, is quite scarce. It appears that the design may have been rushed a little to get these receivers into production during the Korean war since a number of collectors report calibration problems with early production units. In general, they are a bit difficult to service due to their modularized design employing sub-minature tubes with wire leads which are soldered in place. The lack of extender cables also makes servicing somewhat of a headache.
The shore based version of these sets are known by the designation AN/FRR-21/22/23. The only difference I have noticed is the addition of 19 inch rackmount brackets on the side of the case. I have owned a number of the AN/SRR-13A (and FRR-23A) sets and all have had a 2 section Collins mechanical filter in them. The bandwidths are 1.0 and 3.0 kHz and the IF frequency is 200 kHz.
RCA had quite of number of contracts with the US Navy for top-of-the-line communication receiver families starting with the RAA and RAB in the early 1930's, RAK and RAL (mid 1930's), RBB and RBC (1940) and the AN/SRR sets in 1950. Personally, my favourites are the RBB/RBC's."
|Teletype bays in the Communications and Control Room (CCR ) aboard the aircraft carrier HMCS Bonaventure. (Photo # BN-4100 courtesy DND, Canadian Forces Joint Imagery Centre provided via by Robert Langille)|
A transistorized frequency shift converter which superseded the FSC 107. It was designed for frequency diversity radioteletype broadcast reception and single/dual channel reception.
CU-5032/URR Antenna Coupler
|CU-5032/URR Antenna Coupler. AMC 6-5/70. (Photo courtesy
Frequency Range: 2 to 30 MHz
Outputs : Six ; 70 ohms impedance each .
Primary Power Requirements:115/230 volts, 60 cps, 1 phase, 150 watts
Physical: 8-3/4 in H x 19 in W. x 12 in D.; Weight 46 lb.
Manual: BRCN 4134
The AN/CU-5032/SRR is a broadband amplifier consisting of a detachable, low-noise, push-pull, pre-amplifier; a low-frequency, cut-off filter; two distribution lines; six push-pull, isolation amplifier output stages; a test oscillator and metering circuit, and a power supply.
Signals at the antenna input are amplified by the pre-amplifier and fed through the distribution lines to the six power amplifiers. Each power amplifier provides an output for a receiver. The low frequency filter is effective in the broadcast band and may be switched in or out as desired. The test oscillator and metering circuit permit each output stage to be checked for overall performance.
AN/URT7 VHF Transmitter
This was a general utility VHF transmitter and looked very similar to the AN/URT502 transmitter. It had a frequency range of 115 to 156 MHz with a power input of 30 watts. There were four crystal controlled channels available, but in an emergency, a master oscillator could be used. Normally, the URT7 was used in conjunction with the AN/URR21 (RCK) receiver and was the successor to the TDQ transmitter. In addition, there was a variety of commercial transceivers fitted to cover the Maritime Mobile VHF band.
Prior to 1968, the RCN used a VHF 'intercom' in Halifax harbour which also included the Admiral's office. The last two letters of the ship's call sign was used for identification. It was an excellent system, but it could not be used today, since the last two letters of a call sign may be common to several ships.
|D649/K649 MuFAX Chart Recorder
Manufactured by Muirhead, UK, this is a chart recorder used for the reception of meteorological weather maps and wire photos by radio. The MUFAX audio input signal was usually provided by an R1051B receiver. In the MUFAX, audio was converted to current pulses which passed through a helix, across the paper to the writing edge. Chemically treated paper would be marked each time a current pulse was applied to the helix. When scanning was completed, a viewable picture was produced. The D649 chart recorder was used as far back as 1956 aboard HMCS Labrador. Because the MUFAX paper was impregnated with chemicals, it was sometimes stored in the cook's refrigerator abroad ship. This would prevent the paper from deteriorating. This machine was widely used in the Canadian Forces and the Coast Guard. (Photo by Jerry Proc)
Jacques d'Avignon VE3VIA, provides some background information on the MUFAX. "These machines were manufactured by Muirhead in the UK and first appeared in Canada when the Muirhead equipment was chosen to equip weather offices across Canada with facsimile equipment.
In the early 1950's (1954 or 1955) the Department of Transport, who operated the weather service at the time, needed a facsimile circuit that would cover the country and enable all the weather offices to receive the same weather maps compiled by a central office. This office, called the Central Analysis Office, was located in a temporary building at Dorval airport in Montreal.
CN (Canadian National) telegraph was tasked to implement this fax circuit using their existing long lines across Canada. Muirhead equipment was chosen for the recorders and scanners for this circuit. To serve the Arctic weather stations (Resolute Bay, Frobisher and a few others), two radio transmitters were also used; one transmitter was located in Edmonton and one in Montreal".
Radio facsimile is slowly disappearing with more and more stations being closed every year. As of 2009, CFH was still broadcasting weather charts to the Atlantic but that came to a sudden end in November 2010. The January 2011 edition of Monitoring Times reports that the Canada Navy suddenly closed down its WEFAX/RTTY facility which sent weather data broadcasts on the well known frequencies of 122.5, 4271, 6496.4, 10536, and 13510 KHz.CFH broadcast radiofacsimile weather charts at the top of the hour, then filled in the rest of the time with radioteletype text. The sudden disappearance of weather FAX and radioteletype text transmissions among military users is typical . As soon as everyone finally has the latest satellite gear installed, it’s bye-bye to old technology.
At least for now (November 2010), RTTY transmissions are still being sent from CFH. The most commonly reported frequencies are approximately 5097, 10945, and 15920 kHz.. Messages are sent at 75 baud and employ an 850 Hz shift. All channels idle on the mark tone, with the following marker transmitted every thirty seconds: “NAWS DE CFH ZKR F1 [frequency list] AR.” NAWS is a collective all-vessels call sign meaning Notice to Allied War Ships. ZKR is a military procedural signal meaning “I am maintaining a watch on… [frequencies].” AR, of course, means “end of message.”
TMC, more than any other manufacturer, designed equipment with a "building block" configuration. In other words, you could take a basic AM/CW receiver and add a SSB converter; if you wanted space diversity capability, you added a second receiver that could be controlled by the first one, RTTY converter?....no problem.
TMC SBG-1 (a.k.a. AN/URA-30) is a 0 to 1 watt Single Sideband Generator. The model number refers to full 19" rack of equipment comprising of the following units:
CBE-1 (O-714/URA-31) Sideband Exciter
CHG-1 (AM-2505/URA-31) Frequency Amplifier
CMO-1 (O-716/URA-31) Controlled Master Oscillator
CLL-1 (O-717/URA-31) Controlled Oscillator
CHL-1 (CV-928/URA-31) Divider Chain
CPP-5 Power Supply (for CHG-1) - Note: CPP-5 will not be present if CPP-1 (PP-2561/URA-31) is mounted on back of the frame.
CPP-2 (PP-2562/URA-31) Power Supply
A similar rack full of equipment supplied with everything above EXCEPT the CBE-1 Sideband Exciter is known as TMC Model CPO-1 (AN/URA-31) Controlled Precision Oscillator. According to the April 1966 TMC catalogue, the price for the SBG-1 was $11,875. The SBG-1 was normally used as the exciter for a large transmitter such as the TMC SBT-1K (Sideband Transmitter, 1 kw), GPT-10K (General Purpose Transmitter, 10KW), GPT-40K (General Purpose Transmitter, 40 kiloWatt), etc. It was this big because this was the only way to generate a low level signal with the stability rated at 1 part in 100,000,000 in the 1960's.
|The rack in the photo belonged to a deceased ham. Click to enlarge. The Vancouver Radio Labs VRL receiver is not part of the TMC sideband generator kit. The units mounted in this rack are featured below. (Photo via Andre Guibert)|
|Frequency Amplifier Model CHG-2 (from the smaller tag) The larger tag is the system identifier.|
|Model CMO-1 Controlled Master Oscillator|
|Top unit: Model CBE-1 Sideband Exciter. Bottom unit: Model CSS-1 RF Oscillator.|
|TMC Model CPP-2 Power Supply.|
|All photos in this table via Andre Guibert|
Like any piece of equipment, a radio set has a finite life expectancy with the military. As a general rule, this expectancy is twenty years. Like any other system, advances are continuously being made, however, it is not always desirable to incorporate such advances in military communications systems. The major reason for this is the cost of procurement and proof of reliability of new systems. Radio equipment provides continuing service in peace and in war. New radio systems are seldom fitted purely for the sake of improvement unless there are changes in NATO requirements, Canadian federal radio regulations, or amendments to International regulations.
In 1969, the RCN considered the following gear (specific to HAIDA) to be obsolete: AN/URR35 UHF receiver, CM11 transmitter, CPRC26 portable radio, CSR5A receiver, FSC107 frequency shift converter, FR12 D/F receiver, Model 14 T-D, Model 15 Teleprinter, MSL5 LF receiver, PV500 HM transmitter, and the TED3 UHF transmitter. In this time period, much of the existing UHF gear faced obsolescence because it required a continuous supply of crystals, did not have a rapid tune facility, did not have 50 KHz channel spacing and suffered from a high failure rate.
By 1978, the typical radio configuration aboard a destroyer was five URC 32's, seven WSC 510's, seven Racal receivers and an SRD 501.
Morse code was an important means of communication right into the early 1990's.
The basic keying method for sending automatic Morse in both the RCN and USN was the Wheatstone tape which could be run at various speeds. In the RCN, it was used for fleet broadcasts as well as the time honoured SBX's. Wheatstone tape was the "format standard" of its day. McElroy, Teletype, Kleinschmidt, Boehme and Creed were among the principal manufacturers of Wheatstone reperforators.
Wheatstone tape was about 1/2" wide, made by McElroy and had the same texture as the paper tape used for teletype transmission. The configuration for dots and dashes consisted of two hole pattern. To represent a dot, two holes were punched one above another and on either side of the sprocket holes. The dash was a single hole on the top line with the bottom line unpunched, followed by a single hole on the bottom line with the top unpunched. Spaces between characters was a measure of unpunched tape. The output tape would then be fed to a keying head for transmission.
|This is blank tape for Kleinschmidt, Creed, McElroy and similar perforators. It is about 0.47" wide; the roll is 8" in diameter with a 2" center hole. Spartan was a supplier of tape for reperforators but was not involved in the business of manufacturing them. (Photo courtesy of Artifax Books)|
|A section of Wheatstone tape representing the letters J .--- and E . (Graphic by Jerry Proc)|
|This sample of standard Wheatstone tape shows a CQ calling sequence.
by Chuck Swiger)
The characters are formed as:
There were varying configurations of Wheatstone punching. One of the RCN's variations was dash as upper hole punched and next lower hole punched.
|A Teletype Corporation Wheatstone reperforator. Note the chad chute and collector box down the front of the machine. (Photo by Chuck Swiger)|
When ships were in harbour for long periods, such as a refit, the radiomen copied Standard Buzzer Exercises (SBX's) to maintain their expertise. If the radio equipment was functional, they copied Morse exercises from a training frequency. If the radio equipment was unusable (lack of power or landed maintenance), the men went to the 'morse pool' to maintain proficiency. The Morse pool in Halifax and Esquimalt used low power transmitters to serve the ships in harbour.
Allan Riley provides a detailed explanation of SBX's. "These SBX's were sent at 22 wpm and consisted of a plain language message, a 40 group encrypted letters message; a 20 group encrypted digits message and 5 short transmissions. During World War 2, SBX's were similar in format except a foreign language (usually French) message was also included.
Messages were broadcast to NAWS - a collective NATO call sign. The headings of the messages were sent 'words twice'. SBX's were of the same format as genuine messages, except for the operating signal ZEU which designated them 'for exercise'. Z signals were used by themselves or in conjunction with Q signals. The text of the encrypted (letters) message had the 'key' letters in phonetics - the key, of course, showed how the rotors were to be set in machine cipher. The "key" group in the 4 digit cipher was also at the beginning of the text and repeated at the end.
The five short transmissions were used for practice in receiving procedure signs, usually called prosigns. Call signs in the short transmissions group sometimes consisted of 3 letter shore station call signs types or the 4 letter call sign types used by ships".
A document known as ACP 124 defined the formats and regulations for the transmission and reception of radio telegraph messages and was used by the NATO member nations until Morse Code was abandoned as a means of communication. It focused on accuracy, speed and security and was last upgraded to revision 'D' in 1983. On September 1, 1993 all CW related services including training ceased to exist in the RCN.
Jack Dennet of Orleans Ontario, describes the complement of test equipment that was usually available aboard ship. "During the last 30 years, DDE and DDH class ships typically carried a Stark tube tester, a frequency counter, audio and RF signal generators, multimeters and a spectrum analyzer. It was just enough to get the job done.
In the period from 1963 to 1985, radio operators who initially trained as operators at the Leading Seaman/Master Seaman level, were sent on Trade Group 3 radio courses where they were trained as technicians capable of carrying out first line maintenance when the ship was at sea. They were responsible for keeping the gear in operational condition and worked long hours to correct faults. A ship carried many replacement parts, however, if a shortage was encountered, it was shipped to the next port of call. Any equipment which could not be repaired was left unserviceable until the ship arrived in home port and the dockyard technicians took over then.
As someone who has been involved with the new Canadian Patrol Frigate program, things have changed greatly in the area of maintenance. Most repairs are only taken down to the printed circuit board level. The technician is aided by extensive fault finding flow diagrams as well as the built-in diagnostic features. This approach reduces the down time of the equipment and leads to a ship which is more operationally ready than we ever had in the past".
Raymond Baines of Halifax N.S., recalls his experiences as a shipboard technician. "My first ship as an electronics technician, was the Gatineau. At the time, she was the most modern ship in the RCN. There was an electronics workshop just opposite the Captain's cabin which was on the same level as radar operations and Radar 1 and Radar 2 spaces. From that office, we worked on radar problems and as I recall, Radio 3 which was the Electronic Warfare office. For maintenance of communications gear, there was a bench in Radio 2. Sonar had a similar setup for the tech assigned to that area. We carried all the required test equipment and spares to keep the equipment running for the duration of any voyage. If a critical part was required, it was forwarded by whatever means necessary or we could borrow parts from any NATO ship. All spares were cross- referenced with NATO part numbers".
Keith Kennedy of Surrey B.C. comments on the integration of the Canadian Armed Forces in the late 1960's. " Ottawa, in its ultimate wisdom, decided that radiomen were radiomen so they started sending army and air force radio personnel to sea. They were trained as operators only and were not versed in maintenance, could not do cipher work, were not seamen, and for the most part, hated the job. After a period of chaos, the situation was straightened around and it was recognized that seagoing radiomen were of a different breed and no more Pongos or Pigeons were sent to sea. I really felt sorry for these chaps because it sure wasn't the reason why they had signed up with the Armed Forces. Eighteen years after integration, the situation has nearly returned to the same point when the experiment was started.
By 1975, Canada had withdrawn from the Commonwealth ship/shore system for reasons best known to the Trudeau government. The workload for the shore stations had diminished significantly and most communications employed auto-ciphered teletype".
Keith goes on to comment about his final days in the service. "In 1985, half way between Singapore and Bangkok, I decided that sea life wasn't fun any more. I was getting too old to play this young mans game and the living conditions at sea were wearing the body down. For these and other reasons, I applied for my release. I have enjoyed my life as a sailor, a seamen, and a sparker and would not trade my memories for the world, but I must candidly admit that I do not yearn to relive or go back to the sea as many of my contemporaries seem to do. I do not miss the navy life, but at times I do miss the sea and especially, I miss my mates. If I have learned anything from all those ships and all those years of service, I suppose that go with the flow summarizes it best".
Over the course of decades the navy went through a series of name changes for the radioman. Some of the different titles were: Communicator Radio; Radioman; Communications Operator; Radop; Comop; Radioman Sea, then, Radsea.
Credits and References:
1) History of SSB http://www.sacmarc.org/archives/ssb.htm
2) Tom Brent <tgb(at)telus.net>
3) Robert Langille <ewcs(at)ewcs.ca>
4) Sandy McClearn <smcclearn(at)ns.sympatico.ca>
5) Jacques d'Avignon VE3VIA <monitor(at)igs.net>