CFS Alert: Photos 2 - Technical

August 1958: Operations Room looking south. The operating positions are in the foreground with maintenance near the back.  (Alert photo pool  via Joe Costello) 
SSeptember 1958: This is a portion of the Operations Room. In the rack, at the center of the photo, are three antenna multicouplers and patch panels. To the left are a pair of Revere T-700 series reel-to-reel tape recorders. At the right is the BC-221 frequency meter of WWII vintage. The device atop the rack is unidentified at this time.  (Alert photo pool via Joe Costello) 

In those days it was not permitted to have a receiver connected directly to an antenna. This was the practice of some operators to bypass the noise produced by the vacuum tubes in the antenna multicoupler. This why the shift supervisor controlled access to the multicouplers.

August 1958: Intercept position. Theses were the best receivers in their heyday. (L-R) Collins R-388/URR ; Hammarlund SP-600 and the RCA AR-88.  (Alert photo pool via Joe Costello) 

August 1958: Cpl Warman of the Royal Canadian Corps of Signals, performs a delicte adjustment on a Hammarlund SP-600 receiver with a crowbar.  (Alert photo pool via Joe Costello) 

August 1958: This photo is simply titled VHF reflector type antenna erected on an eight foot mound of earth to keep it clear of snow. Can anyone explain how this works? Contact: (Alert photo pool via Joe Costello) 

1978: The Communications Centre was equipped with a wind speed and direction system. At the  left was a dial for indicating wind direction while the right one was driven by an anemometer which indicated wind speed.  This equipment had a two fold purpose. First, it told personnel when the  waste incinerator could not be used especially if the wind was coming from a certain direction or a particular direction. Secondly, SigDev used a VHF antenna that was on a mast with a rotor.  It could not be swung above a certain wind speed, so the operator had to call  the ComCen on windy days to make sure whether the antenna could be rotated or not.  (Believed to be a DND photo)

alert_kw26_1978s.jpg 1978: This was Alert's Communications Centre (ComCen) just prior to the construction of Polaris Hall (1980), the main operations building.  Click image to enlarge. On the right side are four KW-26/TSEC crypto machines. These are likely  'C' models. In each rack from the top down is the receiver, receiver power supply, transmitter and transmitter power supply.  At the left are Teletype Corporation Model ASR28's (aka AN/UGC-6K), three of which are elevated so they can be operated without needing a chair. (Believed to be a DND photo)
There are some other details which can be seen in the ComCen above photo. Next to the door is a poster which says "Keep Smiling".   In the lower left corner is a Hewlett-Packard Model 3400A true-RMS voltmeter, 10 Hz to 10 MHz. There is a burn bag situated in front of one of the teletype machines and in front of the exit door. All classified waste, such as used tape and hardcopy would have been placed into bags like this. All that's missing here is smell of vacuum tubes, hot teletype oil, and the continuous cacophony of all the machines operating all at once.  Does anyone know what equipment might be lurking in the right rear corner of this room? Contact: . As technology moved forward, the 28ASR's were replaced with Teleteype Model 40's.


Russ Pastuch, VE3YOW/VE3FSN, was a civilian working for DCEM (Comms).  Sometime, during the 1976 period, he remembers installing a microwave link from the remotely controlled transmitter site and back to the newly constructed Lancaster Hall  using  a Marconi MCS-6900T microwave terminal with DMT1 mux at each end. .The microwave system was intended to replace 4 to 5  miles of multi-pair copper cable.Can anyone provide any further details.? Contact:

While on the subject of  instaallation, tragedy came just before Christmas 1964, when the weather suddenly turned bad and one of the radio towers collapsed while it was being erected.   Two of the three technicians were blown off the rig which collapsed because of high winds. One died shortly after the fall  while the other eventually died several days later. It wasn't possible to get a Medivac back to Thule Greenland on account of the weather.  When the weather finally cleared, the third lad was flown home to Winnipeg. The tower installation was eventually completed but  in hindsight, the work could have been postponed to the spring or summer since there was no urgency on the completion date. When a storms came up near the North Pole, they often lasted gor days and were scary..

This display, at the Communications and Electronics Museum in Kingston Ontario, depicts a Dual Intercept position at a SUPRAD station typically from the 1980-1990 period. Both the Dual and Single Intercept positions were still in use at all SUPRAD stations, and particularly CFS Alert, until around 1994/5. Normally there would be a desk and chair provided in this position but due to space limitations they have been omitted from the display. A hook for the red handset was not provided in the display. (Photo by Jerry Proc)
Mike Bostwick served as a 291 Communicator Research Operator from 1976 to 1997 and was stationed at Masset, Alert, Gander, and Leitrim. He provides some general information about the Dual and Single Intercept positions.

"Basically the Dual intercept position could be used for variety of jobs. Either strictly as a teleprinter position, a teleprinter/Morse position for copying both sides of  Morse code conversation, and lastly as a control and outstation. A teleprinter position was intended for the reception and printing of carrier wave Baudot traffic.
If used as a  teleprinter printer position there were normally at least 4 to 5 of these bays in a row with a desk or table at each one. If used as a Morse position, then a rolling table with a typewriter would be at right angles to the bay.

As operators we never had a need to know what the RF Distributor panel did. The Pylon 364 Audio Panel was basically a telephone system used to communicate with other positions on the floor such as  Signal Development to the Direction Finding  position as an example. The Block Task Controller (BTC) and some other positions also had the ability to call other stations to coordinate intercept or find out scores from a hockey game or to co-ordinate the various Morse positions at a site to make sure all the schedules were met.

The Pylon Tuning indicator was mostly used for printer signals but could be used for Morse. It was basically a small oscilloscope, that when a signal was tuned correctly would display a line with a circle that danced around the line. As for the Single intercept position, I don't remember there being a lot of them if any. Most positions had at least two receivers so an operator could hear both sides of a Morse or voice conversation. There would also be a rolling table and chair for the operator to sit at. Normally all positions had the Pylon 125 tuner and the 364 audio panel/phone system".

alert_intercept_dual_095_364_jacks_s.jpg 1, 2 and 3: This image includes, from top to bottom,  a) Pylon Model 095 Double RF Distributor panel. b) Pylon 364 Audio Panel with red handset. c) Signal patch panel. Manufacturer unknown. 
alert_pylon364_rears.jpg Pylon 364 Audio Panel: Rear view. 
alert_patpan_conn.jpg Closeup of the signal patch panel connectors made by Trompeter Electronics.   Four of the holes on the panel have a cover installed to block the insertion of connectors where there are no jacks installed. The maximum signal frequency handled by this panel was 1 MHz and that was the limitation of the distribution amplifier which was connected to it. 
alert_intercept_dual_m7000_s.jpg 4 and 6: The Universal M7000 Communications Terminal is a multimode teletype decoder which decodes Morse, Baudot, RTTY, SITOR, ASCII, ARQTOR, FECTOR, TDM2/4, ARQ-E, ARQ-E3, Packet and FAX. FAX is supported to the parallel printer port and monitor port. An LED bar graph is used for tuning.  It provides an output to a printer, screen, or serial port. Requires 115/230 VAC 50/60 Hz 25 watts.
alert_intercept_dual_dvd2_s.jpg 5: Dual Video Display consisting of pair of DVD-1 display units integrated into a common front panel. It was used for the display of signals decoded by the M7000 communications terminal.
alert_intercept_single_6778_s.jpg 7 and 9: Racal RA 6778C Receiver. General coverage receiver. 10 KHz - 30 MHz, LSB/USB/AM/CW/ FSK. Controlled by microprocessor. Double conversion, with IF's at 3.4 and 1.4 MHz. filters) Crystal filters for bandwidths of 8.0, 3.2, 1.25, 0.75, 0.4, 0.25, and 0.15 kHz. TEMPEST certified. Two receivers were used when copying Morse or voice transmissions which operated on a split frequency. 
Racal 6778Q Receiver Same as RA-6778 except it lacks a tuning dial. (Keyboard only)
alert_intercept_dual_tuneind_125_s.jpg 8: Pylon Model 125 Tuning Indicator. 
Pylon Auxiliary power panel at bottom of cabinet with one convenience receptacle. 
All photos in this table by Jerry Proc
PYLON 095 RF (Double) Distributor Panel

Pylon Electronics provides the following description for the 095 RF panel since there is no manual for it. "We do know that the circular military connectors at the back of the unit were connected to each of the BNC connectors. One circular mil connector was attached to half the BNC connectors and the other mil connector was attached to the other half of the BNC connectors. Unfortunately, we do not know how this panel was connected or used in the field."

PYLON 364A Audio Panel

The Pylon 364 Audio Panel is a dual channel, pushbutton operated audio line selector in which any combination of six audio inputs can be selected and mixed. This unit can also be interconnected to a telephone line which supports tone dialing with a provision to patch the audio line selector output to the telephone line.  Revision 3 of the manual for the 364A is dated February 1991 so it's assumed the 364 was introduced to the marketplace prior to that time frame.


Audio Line Input:
    Number of lines - 6 maximum
    Impedance - 600 ohms, balanced.
    Level - 0 dbm
    Gain - individual front panel control for each line.

Audio Output:
    Front Panel - Two stereo headset jacks (ring, tip, and sleeve).
    Rear Panel - Two pair screw terminals ( in parallel with headset jacks)
    Impedance - 600 ohms. Level - 9 dBm each channel + 20 dBm max.
    Frequency Range  - 250 Hz to 4 KHz +/- 3 dB

    Front Panel - One microphone jack (tip and sleeve) input - Uses left channel of headset jack output (when
    activated by the ICOM switch)
    Volume control for solid state Ringer.
    Uses Northern Telecom Digitone Push Button Dial.
    Selector (hook) Switch is illuminated when selected.

 Rear Panel:
    One pair screw terminals for Northern Telecom handset - One pair screw terminals for Mitel
    SX-2BB two-wire PABX connection.

Phone Patch:
    Front Panel - Patch Switch - (illuminated when "patched")
    Gain control
    Coupling - Transformer
    Level  -l0 dbm

Power Supply: Input 115 VAC, 60 Hz, 20 VA


To provide a better understanding of the how the audio panel works, here are some excerpts from the operating manual.

A) Line Selection

The six input signals may be selected on the left, right, or both channels by depressing the appropriate line/channel button. When the line is selected, a lamp in the selector switch will be illuminated.

A level control for each line is provided below the switches.

All six lines may be selected individually or in combination to appear on the left, right or both channels.

The output is available at both the headphone output and monitor output on the front panel as well as the output terminals on the rear panel.

B) Intercom

When connected to a telephone line the left headphone, in conjunction with a microphone, may be used to access the phone line. Alternatively, a handset may be used. An incoming call will be signalled by the I/C lamp flashing and by the tone ringer, if it is turned on. The control under the tone ringer speaker contains an ON/OFF switch as well as a level control for the tone ringer. To answer a call, depress the I/C switch and use either the handset or microphone/headset combination, whichever is connected. To disconnect from the line, depress the I/C switch.
The indicator lamp should then go out. To place a call, depress the I/C switch. Once a dial tone is obtained, place your call using the front panel keypad to dial.

C) Patch

When the phone line is in use, you may patch the audio selected to the right headphone channel into the phone circuit. To do this, depress the Patch switch. The level control below this switch allows a small adjustment of the level fed to the line.


The Signal Patch Panel t was capable of distributing signals up to 1 MHz in frequency as dictated by the upper frequency response of the Pylon 3789 distribution amplifier that was connected to it. The connectors are industry standard and designed to handle low power video and RF signals of 75 ohm impedance and up to 1 GHz. In spite of having nearly identical appearances, the 50 and 75 ohm version of the plugs and jacks are not compatible and they won't mate. The markings on the front panel are: PY3789 #1 OUTPUTS A1, A2 A3, A4, B1, B2, B3, B4, C1, C2, C3, C4. This is repeated on the right side for OUTPUT #2 so this means the panel can accommodate the outputs from two 3789 amplifiers. In addition,  the panel interfaces the BNC style output jacks on the  3789 rear panel to the Trompeter jacks.

What is described is the arrangement for the top row of jacks. The bottom row of jacks is unlabelled. Also, the three rightmost jacks in the bottom row have covers over them thus rendering the panel asymmetrical.

Chip Veres, a communications technician with WLRN TV and FM in Miami, FL suspects that the 3789 panel  might have been used for VLF-LF signals where the phase is important (PSK). " Its bandwidth is not enough for video, let alone HF, but the phase is specified to error less than 10 degrees at 1 MHz.  The station operator mentioned the availability of several Beverage antennas, so maybe this amp was used to get the long-wave signals to different receivers.  It may also have carried a phase reference signal from the cesium clock".

Chris Collin offers some additional details about the panel. "At one time, we used a combination of jacks.  I remember using 1/4" phono jacks for audio, BNC along with Trompeter jacks all on the same rack.  The patch panel could become a nightmare, especially in a SIgDev position!  We  also had adapter connectors which could convert from one connector type to another.

Some situations had antennae being attached to patch panels. For anything above LF, the connectors needed to be of the higher performance variety. We would also need to patch video in some situations, or IF frequencies, often 22.4MHz . In the end, I suspect it was just easier to install Trompeter jacks everywhere, as this reduced the requirements for all  kinds of cables and connectors, at least at the operator level. SigDev'ers usually had access to various connectors, as we would  sometimes bypass the jack panel, and go directly to the equipment especially for a new or experimental situation, and where the jack at  the back of the equipment was not connected to the patch panel.

SigDev'ers would frustrate technicians at times by hooking up gear in new and novel way as an experiment in order to process a difficult signal.  Technicians liked things all sorted and installed neatly and correctly but we would often run lines in and out of the racks in new and strictly unofficial ways!

For most situations, BNC connectors  would have been fine, but there were advantages to having a patch panel like the Trompeter type for ease of use, training, and expansion capabilities.  Generally speaking,  for most positions the patches would be made once and rarely did they change".

Mike Bostwick confirms that panels weren't utilized very much on a normal intercept bay.


The Pylon 3789 Distribution Amplifier (circa 1980) is a 19" rack mountable unit, designed to perform the
following functions:

a) Distribute each of 3 channels to 4 outputs each with a maximum isolation between the lines.
b) Provide by means of a calibrated R.M.S. voltmeter, a method of monitoring all input and output signal levels.
c) Display by 3 front panel LED's, an input overdrive condition.


Inputs : Up to 3 rear panel BNC connectors; 50 to 600 ohm termination; up to 5 volts RMS maximum.
Outputs: Up to 12, rear panel BNC;. Maximum drive to a 50 ohm load is 5 volts RMS. Capable of withstanding
a momentary short circuit
Frequency Response: flat to 1 MHz. A phase shift of 30° is observed between input and output at 1 MHz.
Size: 3.5in. H  x19in. W x 12.5in. D
Weight: 11 lbs.
Power 115 VAC, 60 Hz, 36 watts nominal; 60 watts maximum.

3789 Front View (Photo courtesy Pylon Electronics)
3789 Rear View  - the 3 inputs are at the right side. Photo courtesy Pylon Electronics)


The M-7000 was introduced by Universal Radio in Columbus Ohio in the 1987-1988 time frame by it's President, Fred Osterman. It was built by Digital Electronic Systems Inc. of Florida. The May 1989 edition of the RTTY Listener monthly periodical announced that the Canadian government  purchased fifty Universal M7000's with video, fax and real time clock options.

Reception Modes:
Morse Code 5 to 120 WPM with Auto ranging
RTTY Baudot 45, 50, 57, 75 and 100 baud (60, 66, 75, 100 and 132 WPM)
RTTY Baudot 37-251 baud non-standard rates
ASCII 150, 300, 600 and 1200 baud.
ARQ-M2 TDM 86, 96 and 100 baud.
ARQ-M4 TDM 172, 192 and 200 baud.
Packet 300 and 1200 baud.
FAX Facsimile 60, 90, 120 and 240 LPM AM/FM
VFT [FDM] HF 8/12/16/24 Channel.
VFT [FDM] SAT 50 Channel. [in v7 only]
ARQ-E 48, 64, 72, 86, 96, 144 and 192 baud. [in v5/v7 only]
ARQ-E3 48, 64, 72, 86, 96, 100, 192 and 200 baud. [in v5/v7 only]
ARQ-S 4, 5, 6 or 7 character groups. [in v7 only]
SWED-ARQ 3, 9 or 22 character groups. [in v7 only]
FEC-A 96, 144 and 192 baud. [in v7 only]
FEC-S 96, 100, 144, 192 and 200 baud. [in v7 only]

Some Key Features:
Speed Readout: Indicates the incoming RTTY transmission rate.
Diversity Reception
Filter Control Wide-Narrow-Normal
Four Alphabets: ITA2, MIL, TELEX, Cyrillic

The Universal M-7000V2 was an M-7000V1 production unit that had a Ver2 ROM upgrade adding  ARQ-E and  ARQ-E3 modes. The Universal M-7000V3 was an M-7000V1 production unit that had a Ver 3 ROM upgrade adding:   ARQ-E, ARQ-E3, ARQ-S, FEC-S, FEC-A and SWED-ARQ modes. The Universal M-7000V5 production version added these modes over the Ver 1:   ARQ-E and ARQ-E3. The Universal M-7000V6 was an M-7000V5 production unit that had a Ver6 ROM upgrade adding:   ARQ-S, FEC-S, FEC-A and SWED-ARQ modes. The Universal M-7000V7 production version added these modes over the V1:   ARQ-E, ARQ-E3, ARQ-S, FEC-A, FEC-S, SWED-ARQ and VFT 50 channel.

PYLON DVD-1 Display

The DVD-1 is a programmable dual channel display instrument enabling an operator to visually check the integrity of incoming BAUDOT and ASCII formatted data. Incoming BAUDOT data is converted to ASCII and then retransmitted at 2400 baud. If the conversion of BAUDOT encoded data to ASCII is not desired, an internal jumper may be installed for either channel. When installed, the affected channel(s) will retransmit BAUDOT encoded data at the incoming baud rate (up to 19,200 baud). Incoming ASCII data is retransmitted at the incoming baud rate (up to 19,200 baud).

If the operator must read the incoming data to check its integrity, the incoming baud rate needs to be limited to approximately 600 baud. This rate can be increased to 2,400 baud if the operator is visually scanning specific data fields or characters. Higher baud rates will scroll the display too rapidly.

The Serial Video Module is a programmable video interface providing data conversion and communications. This module converts incoming BAUDOT encoded data to ASCII (unless the data conversion mode is disabled) before it is transmitted. Incoming ASCII data is retransmitted in the same format. All incoming BAUDOT and ASCII data is stored in a screen memory for display via the CRT.

Serial format and baud rate of the Serial Video Module's input and output can be selected independently.
BAUDOT or ASCII encoded data is received by one port of a dual asynchronous receiver/transmitter.
A microprocessor polls the receiver for activity. Incoming BAUDOT data is converted to ASCII
and then transmitted at 2,400 baud. If the data conversion mode is disabled, the incoming BAUDOT data is retransmitted in the same format and incoming baud rate. Incoming ASCII data is retransmitted in the same format and baud rate (up to 19,200 baud).


* BAUDOT/ASCII data communications and video display.
* Full 70 character x 25 line display.
* 7 x 7 or 8 x 8 characters displayed in 8 x 8 character cell using 9 x 9 pixel array.
* Unrecognized character indicator.
* Variable baud rate 0 to 19,200.


* Dimensions: Height 267 mm (10.5 in.) Width 483 mm (19.0 in.) Depth 533 mm (21.0 in.)
* Weight: 24.2 kg (53.2 lb) net
* Power requirements: 120 VAC, 60 Hz, 0.8 A

Revision 1 of the manual is dated 1 March 1988 so its likely the DVD-1 was introduced prior to that time frame.

PYLON 125 Tuning Indicator

The PYLON 125 Tuning Indicator is a highly accurate display which was used as an aid in tuning a receiver to a particular frequency. A 2" x 2" square CRT display provides the visual display. This device can be used with receivers which employ either 100 kHz, 455 kHz or 1.4 MHz Intermediate Frequencies (IF). The desired IF frequency of operation can be selected by changing a crystal on the Tuning Indicator Module at the rear of the unit and reselecting the associated DIP switches.  Setting up the desired IF frequency is done when the equipment is first installed and would remain that way for the duration of the in-service interval.  For 1.4 MHz , 455 kHz and 100 kHz operation, crystal frequencies of 2.82 MHz , 1.86 MHz and 3.52 MHz  are required. Horizontal divisions on the CRT graticule correspond to 100 or 200 kHz steps depending if the Magnifer is in the 1X or 2X position.   The 125 Indicator was first introduced by Pylon in 1981.

1980-90's vintage Single Intercept position display at the Communications and Electronics Museum , Kingston Ontario. (Photo by Jerry Proc)

This photo was scanned from the 291 Communicator Research Operator recruiting pamphlet (reference # CS 03-0305). The equipment depicted is from the 1990's era. A normal working position would be cluttered with paper. 

The SIGDEV postion had its roots from LRTS (Long Range Technical Search). Anyone in this position would search the entire spectrum from VLF to lower VHF and identify everything heard, except Morse Code. The LRTS course covered modulation methods, such as AM, FM, FSK, etc, and the equipment types which produced these signals such as teletype machines, time division multiplexes, frequency division multiplexes, speech privacy systems, various facsimile systems and electronic aids to navigation.

A SIGDEV position, as depicted above, was standard throughout the system and would likely be found at Alert, Masset and Gander. In contrast, the standard Morse code operator position had two Racal receivers, plus a mill (typewriter) and in later years, a computer. The equipment in this photo is explained in greater detail in the table below. (Photo courtesy National Defence Canada)

alert_6778_rcvr.jpg 1. Racal Receiver,  Model RA6778C.  Sometime operators at Alert would sneak down onto the AM frequencies to listen to WOWO Fort Wayne, Indiana or stations in Buffalo which helped to relieve some of the isolation and the long six month night. (Photo courtesy Hamnet web page) 
alert_3325_small.jpg 2. Hewlett Packard 3325A .Synthesizer/Function Generator. The Synthesizer frequency range is 1 Hz to 20.999999999 MHz. As Function Generator, square waves from 1 Hz to 10.999999999 MHz. This device appears in the 1988 H-P catalog. 

At a SUPRAD station, the 3325 was used to measure frequencies.  In a Sig Dev role, it like the Racal receiver, was also synchronized with an atomic clock in order that the operators could  achieve good accuracy, very quickly.  There were other methods of measuring frequency with slightly more accuracy but that took a little more doing! (Photo courtesy Test Equipment Depot)

alert_intercept_dual_tuneind_125_s.jpg 3. Pylon Model 125 Tuning Indicator. See above for description. (Photo by Jerry Proc)
alert_sd380_s.jpg 4. Spectral Dynamics SD380 FFT Signal Analyzer. This was used primarily to find the keying speed of unknown signals, although it did have other uses, including a further aid to tuning. Screen size: 9". Optionally it had the capability of Octave Band Analysis. It also has a great gimmick - pressing a secret spot on the front panel would clear the screen, and the words "coffee break" would appear. The 'C' version of the unit was released in 1989. (Photo courtesy Government Liquidation) 
alert_2445b_small.jpg 5. Tek 2455B Oscilloscope. This was a 200 MHz analogue oscilloscope  Analogue scopes were used to determine  keying speeds of Frequency Shift Keyed signals. Digital scopes we not suitable for this particular task since they had too much delay. Scopes from different manufacturers were used as well in this position. (Photo courtesy Magic Design Ltd.)
No detailed 
photo available 
6. Model MD1121g  PSK Demodulator -  Used to demodulate Phase Shift Keyed bi and quad signals.  These PSK demodulators were reported to be a frustrating instrument to use. Custom made for DND, it was considered a classified device when it entered service.
7. Model PCM 720 Bit Synchronizer. Made by Schlumberger, it was used to interface bit streams from the various demodulators into a computer system called ACUATOR. (Photo courtesy  inCAV Technologies)

A Bit Synchronizer is a device that establishes a series of clock pulses which are synchronous to an incoming signal. It then identifies each bit in the signal. The desired condition of a bit sync (i.e. lock) when the output data and clock signals match those of the transmitted signal. The bit rate of the output will average to the same as the transmitted signal and the phase will remain in phase within 180 degrees. 

alert_intercept_dual_095_364_jacks_s.jpg 8. Pylon Model 364 Audio Panel. See above for description. (Photo by Jerry Proc)
dsp_5500s.jpg 9. Kay Elemetrics Sona-graph DSP 5500. Used for audio signal analysis.
(Photo courtesy UCLA)
Chris Collin comments on the reception of phase shifted signals. "We developed other techniques that worked better, at least for bi-phase signals. One way was to tune the signal with the BFO off, and using the resultant AF output.  This would produce low amplitude "clicks" as the phases changed. Next , the audio was fed into an ink tape recorder or the Siemens Oscillomink L (which came later).  We would then manually read the output, using a [template] card that we made. It was slow, but it was fine for the signal speeds back in the 1980 's and 90's. By the time phase shifted signals came into wider use, we used a computer to demodulate them".

ACUATOR was an early computer system used for signals analysis. The operator fed binary bit streams from the bit synchronizer, or other device producing bits, (rather than an analogue signal) into the computer. The computer would collect the bits, then subject those bits to different analysis packages. For example,  the operator could plot an unknown signal using various pulse widths. When the correct width was achieved , the sync bits would be visible as a vertical bar on the computer screen. All this used to be done manually using graph paper, but computerizing the process made things so much easier! The system could also collect certain newer signals and store them,  hopefully until some other piece of equipment was developed which could provide an analysis.

ACUATOR did not last all that long, as it was replaced by another, better and more sophisticated system using Solaris computers made by Sun Systems. This was called WEDLOCK.  It replaced almost all the equipment normally seen in a SigDev position except the receiver.

In the lobby of the Leitrim Operations Building, a small area is reserved for old equipment that was used in the past. Racks 2 and 4 (L-R) were marked MP823 which means Multi Position. Here CW, Voice and RTTY was intercepted among other signals of interest. Positions such as this could be found throughout the SUPRAD system.
This is the Multipurpose Position in the lobby of the Leitrim Operations Building. Click on photo to enlarge. The rack pairs are identical. (Photography arranged by Harry Nolan, CFS Leitrim and Pte  R.L. Vaters)
1- Pylon 358A Remote Display for time. 
2- Pylon SVD-1 Single Video Display
3, 6,10 - Racal 6778C Receiver 
4 - Jack Panel
5 - Pylon 125 Tuning Indicator 
7 - AN/TNH-21B Tape Recorder
8 - M7000 Communication Terminal
9 - Pylon 364 Audio Switching Panel

alert_358a_s.jpg Pylon 358A Remote display. Has double digit numeric displays for Days, Hours, Minutes and Seconds. Click to enlarge. (Photo part of above image) 
alert_tnh21_s.jpg AN/TNH-21 Tape Recorder # 5835-01-070-1882; 5 speed, 4 track, 10-1/2" reel;
1/4" tape; 0.937 ips. Circa 1973. Click to enlarge. (Photo part of above image) 
Chris Collin provides more details about the various equipment configurations in a Multipurpose Position. "MP simply meant "Multi-Purpose," as opposed to the "MM" or "Manual Morse" positions, or the "SD" for SigDev.  As such, there was no real standard layout, and in fact, different MP positions in the same room could look different, depending on the tasking.  Example - some might include equipment for signals other than Morse and teletype (RTTY).  The Universal M7000 terminal, and then the M8000 were good in that way, since they could copy several common signals, and having a digital output, the data could be sent to a computer  for processing for signals that those devices could not process.  They could also be computer controlled, which made them great for sites under remote control.  Previously, separate equipment was required to copy RTTY signals and other signal types.  Certain positions might be for printer only ("PP" positions), while others were for other types of signals.  However, most MP positions could handle a variety of signals.

After the end of the Cold War, as tasking changed, so did the racks. Different equipment came into use, as different signals were being copied. While much equipment was designed to be flexible (eg., the M7000), typically certain jobs were done on certain positions, and the equipment for those racks pertained to the particular tasking for that position. Example- the rack layout for signal Y from country X might be different from the racks used to copy signal X from country Y.  Thus, the examples one sees in the Leitrim building lobby are real, but they do not show the entire picture, only a sample representation.

Generally, the racks would be ganged together - normally at least 2, but 4 sometimes 6 were also observed.  The "Printer Position" might have even more, e.g., 8 racks.  Each position would be MP, with the designator also indicating the station e.g., MP801 being Leitrim, while MP501 would be in Gander.  If memory serves, Alert would be MP001, and Masset MP101.  The 4 (or whatever) racks together would all be part of MP###.  If I remember right, the Alert SigDev position (SD001) had 13 racks for one of my tours.

The tape recorders could be used for various tasks.  Often, voice signals were recorded so that the linguists could replay the transmissions over and over again, in order to copy the "gists" more accurately.  New or unusual transmissions were supposed to be recorded, in order for the Signals Development section to be able to do their analysis later on.  Also, during busy times, a signal might be recorded for later processing.  The recorders had 4 tracks:
a) Track 1 had a digital time signal from the atomic clock
b) Track 2 had a 100 Hz tone (also produced from the atomic clock) which was used as a servo to sync the playback to a very high degree of accuracy.
c) Tracks 3 and 4 were for the signals themselves, usually a receiver AF (Audio Frequency).  As the M7000 (and similar) demodulators used AF, this was fine for processing from the  playback.

For VLF positions, the antenna output could be recorded directly, and thus signals reproduced and studied or copied at a later time.

I remember the SigDev positions getting new high-quality reel to reel tapes sometime in the mid-1980's.  They were a much darker brown, and had higher fidelity than the usual tapes.  They were also much more expensive - $25 per tape, as opposed to the few dollars for the regular tapes. Thus, each had a SigDev sticker on the reel, to ensure it was used only in SigDev."

This reference was found on the web for the tape recorder: AN/TNH-21 Recorder-Reproducer Set, Sound, Instruction Manual, National Security Agency, Fort G.Meade, MA, December 1973.

Adler Model 21F electric typewriter as displayed at the C&E Museum, Kingston. This was the replacement typewriter for the older manual  models found at SUPRAD stations. One of its features is the sprocket drive. (Photo by Jerry Proc) 

Jim Troyanek explains the key arrangement: All the keys (letters) are in upper case. If you look at the second key from the right, there is a horizontal bar on it.  That was the key which was used to put the bar or line above the letters, hence they were called "barred letters" and represented the Cyrillic letters of the Russian alphabet.  There were five of them - A  E  O  H  U.  and expressed as barred A, barred E etc.  The composition of barred characters required two keystrokes, one for the bar and one for the letter. If my memory serves me,  the Morse equivalent was: 

Barred A =  .-.-    Barred E =  ..-.. Barred U =  ..-- 
Barred O =  ---.    Barred H = ----

The Underwood Touch-Master 5 was among the last desktop models produced at the Underwood factory in the early 1960s. It too was used in throughout the SUPRAD system.This example resides in the lobby of the Leitrim Operations Building.  Photography arranged by Harry Nolan, CFS Leitrim and Pte  R.L. Vaters)


This aerial photo, taken in the Spring of 1989,  shows the access road (L) and electrical cable right of way (R)  to the Pusher site which is the little dot on the horizon. Because of the Pusher's distance from  Polaris Hall (Ops Building),  its presence is usually not noted by visitors to Alert. (Photo by Marcel Pepin. From the collection of Bill Robinson) 
A small shelter houses the goniometer and support electronics of the AN/FRD-13  Pusher antenna made by Plessey. Here , the low angle of the sun casts a very long shadow.  A description of what may be found at a Pusher site is described in the photo below. Easily seen above, is the access road and the electrical right-of-way.  (Image courtesy Google Earth) 

PUSHER: This is a photo of an AN/FRD-13 Pusher installation taken in 1984 at the US Naval Security Group station located at the Azores. Unlike its big brother, the AN/FRD-10, the Pusher has no operations building in the center of the array. Instead, there is a small shelter which houses the goniometer and support electronics. Generally a Pusher covers the range of 1.5 to 30 MHz. It has two concentric rings of 24 antennas each  and sometimes doubled up to 48 each. The outer ring is 150 metres in diameter while the inner ring is 50 metres in diameter or thereabouts. There is no vertical screen between the rings. (Photo courtesy NSG web site ) 
In March 2014, DND issued a Request for Quotation to overhaul antennas at various sites across Canada.  Shown below are the receiving antennas for Alert. as listed in the RFQ document. The data is copied verbatim.
QTY MODEL No.  of 
1 BEV-750-6K 10 7 feet Wooden Petrie 
750 foot Beverage 
1 BEV-150-5K 3 7 feet Wooden  Petrie
150 foot Beverage
1 Tower 1 60 feet Steel ? Microwave tower
2 ? 8 70 feet Steel ? Three wire rhombic
4 -- 164 14 feet Wooden  DND Long wire Beverage
1 -- 5 1 x 110 feet
4 x 30 feet
Steel DND Crossed loop
2 726-2  2 2 x 140 feet
2 x 36 feet
Andrew Vertically polarized log
periodic antenna.
1 SPQ-230/55 1 84.3 feet Steel Antenna 
HF spiral antenna
1 PVS1120A 48  24 x 20 feet
24 x 39.5 feet 
Aluminum  Plessey Elevated feed monopoles; 
omni directional DF [2]

Notes for the antenna section.:

1) CommScope purchased Andrew Antenna in 2007. Therfore no specs can be found on any of the Andrew antennas.
2) The Plessey PVS1120A antenna is mentioned in the Aigust 1974 edition of Flight International magazine but no photo provided.

Credits and References:

1) Jim Troyanek <intarsia(at)>
2) CS03-0305 brochure provided by Daniel Sweeney<photoartcontact(at)>
3) Chuck McGregor  <cbmcg(at)>
4) Hamnet Web page - Racal 6778 review
5) Test Equipment Depot - 3225 photo and specs.
6) David Smith <drdee(at)>
7) Bill Robinson. Copy for Pusher caption.  <newman-robinson(at)>
8) Pusher Photo.
10) M-7000 info
11) M-7000 info
12) M-7000
13) Art Heatley , Pylon Electronics  aheatley(at)
14) Chris Collin <>
15) Government Liquidation
16) Mike Bostwick  <mjbostwick(at)>
17) 2445B Scope Photos -
18) Tom Adams   <TAdams(at)>
19) inCAV Technologies, 440 w Julian St, Suite 225, San Jose, CA
20) Bit Sync definition:
21) Gregory W. Moore <gwmoore(at)>
22) TNH-21 info
23) Underwood Five
24) Harry Nolan  <hgnolan(at)>
25) Rob Vaters,  CFS Leitrim.
26) Cryptologic Collection Equipments 1977 edition - NAVEDTRA 10251
27) Charles D. Veres <chipveres(at)>
28) DND RFQ for antenna overhauls.
29) Russ Pastuch <solvason.pastuch(at)>
30) Maurice Drew <maurice0404(at)>

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Dec 21//18