Cliff  Chadderton provides this introduction to the Aircraft Detection Corps.
"The story of the Aircraft Detection Corps (ADC) during WWII  is largely unknown to Canadians.  It is the story of the eyes and ears of those charged with defending our shores. At the outbreak of World War II, Canadians faced the possibility that enemy aircraft could enter the country's airspace without being detected.  There was no radar alert system at that time. The country's vast spaces meant the Home War Establishment would need assistance.  As a result, the Aircraft Detection Corps was formed in 1940 by Air Vice-Marshal George Croil.

As the war progressed, the enemy threat came not only from the air but also from the sea.  The most effective observers beyond our shores were fishermen.  They were considered already trained observers and were of valuable assistance to the Aircraft Detection Corps. Many areas were vulnerable to enemy attack, including Halifax Harbour, the Gulf of St. Lawrence, the Hudson Bay area, the great canal locks at Sault Ste. Marie and the vast BC coastline.

In all, close to 30,000 Canadians signed up for the ADC..  Housewives, school children, fishermen and lighthouse keepers became official observers for the ADC (RCAF).  Their job was to scan the skies and seas and report any suspicious sightings of aircraft and vessels – even spies.

The Aircraft Detection Corps was disbanded toward the end of the war when the action in the Pacific moved closer to Japan and also when the radar along the coast was so effective that human observers were no longer seen as necessary".

The Air Detection Corps was divided into three regional units, placed respectively under Western Air Command (WAC), Eastern Air Command (EAC) and, in central Canada, the RCAF HQ. From the Atlantic to the Pacific, 2,692 observer posts were active, decreasing in number as the war progressed. In places where there was no telephone service, radios such as the model ADC-19A were used and issued to mostly to marine people and light house operators. The low power output and the daytime operating frequency did not give these radios much range, so it is assumed the observers were not too distant from an RCAF reporting centre. Doug Betts, an ADC volunteer estimates that perhaps 250 of these radios were built and issued to the ADC.

The ADC’s military personnel made sure that enough civilians were watching the skies in areas that enemy bombers or reconnaissance planes could enter. The ADC handed out documents to assist in identifying the different types of aircraft; telephone companies did their part as well by transmitting free of charge messages intended for ADC stations. Enemy air raids against Canada were so few that ADC volunteers had little opportunities to distinguish themselves. But their reports were useful to locate lost aircraft and the information they provided increased the efficiency of rescue missions.

At war's end,  the RCAF, on behalf of a grateful government, presented some 24,000 sterling silver pins and certificates of appreciation to ADC members. The next part of the story features the ADC-19A transmitter-receiver which was used by observers who did not have telephone service.



Model: ADC-19A
Frequency range: single crystal controlled receive and transmit frequency. For serial 0053 shown below, it was 1792 KHz for transmit and 2192 KHz for receive.
Receiver type: Superheterodyne
Transmitter:  807 final fed with a single oscillator stage and modulated by a pair of 6V6's. Tx adjustments are preset.
Receiver IF: 400 KHz
Transmitter mode: AM voice only
Transmitter output: 10 to 15 watts estimated. Uses screen grid modulation.
HV dynamotor output: 500 VDC @200 ma
LV dynamotor output: 200VDC @60 ma.
Filament power draw: 12 VDC @3 amps (estimated)
Weight: 100 pounds (estimated)
RCAF designator: 10D/7316 , a component of 10D/5794
Circa: July 1943
Comment: Donated to The Harvard Historical Aviation Society Springbrook, AB, Canada in August 2010.

Unless otherwise noted, all photos by Jim Thoreson
It is believed that the ADC19 was fitted in a wooden cabinet so it could blend in nicely in a civilian setting and as a consolation prize,  it would hide hide a bank of wet batteries.
Note the words "Sky Ranger" at the top of the console. These do not appear on any of the schematics. Above that is a pilot light. The word "Listen" has been translated into French. The other two words need no translation because they are spelled the same in both English and French.
Front view showing the dynamotor power supplies and the battery compartment below.
Rear view with cover panel removed. The battery compartment is at the bottom of the cabinet. 

Transmitter/receiver chassis -  front view. 
Transmitter/receiver chassis -  rear view. J1 allows a test meter to measure the oscillator stage cathode current. J2 permits the final stage to be tuned and preset. J3, at the right, is  the microphone input. 
Dynamotor power supply S/N 134 - front view.
Dynamotor power supply - rear view.
Bottom cover plate for dynamotor power supply.

Transmitter/receiver chassis for S/N 0053. D.E.I.L. means Dominion Electrohome Industries Limited while RPA is Radio Production Alliance. .
Transmitter/receiver chassis.
Power supply.
Power supply inspection tag for S/N 134.
Low voltage dynamotor.
High voltage dynamotor. 
adc19a_transceiver_sch_s.jpg Transmitter/receiver chassis schematic. Click to enlarge.
adc19a_ power_supply_sch_s.jpg Dynamotor power supply schematic. Click to enlarge.


Electrohome Limited was an international manufacturer of home electronics, appliances, furniture, and high-tech commercial projection and display systems, and an investor in television broadcasting. The company was  based in Kitchener, Ontario.

In April 1933, Arthur B. Pollock formed Dominion Electrohome Industries Limited with the purchase of the combined assets of two of his companies, Pollock-Welker Limited and the Grimes Radio Corporation Limited. His son Carl became general manager. The company, commonly called Electrohome, originally had three manufacturing divisions: radio and communications, appliances and metal products, and furniture and woodworking. It became a publicly traded company in 1946.

In 1967, the company’s name was officially changed to Electrohome Limited. In 1969, Carl’s son John A. Pollock was made a vice-president and was elected to the board of directors, and in 1972 became president. The late 1970s and early 1980s saw more management changes. During that time Electrohome abandoned television manufacturing and the electronics division focused on commercial and industrial products, including specialized video and data display monitors and large-screen projection television. Electrohome also entered new fields, including reverse osmosis/ ultrafiltration systems and video-game monitors. By the end of the 1980s, the company withdrew completely from the manufacturing of consumer products to focus on the two remaining business segments: broadcasting and commercial data and video projection and display systems.

In 1998, Electrohome was divided into two entities, Electrohome Limited and Electrohome Broadcasting Inc. (EBI). The display and projection businesses were sold in 1997 and 1999 respectively and in 2004 the last manufacturing plant and head office building on Wellington Street in Kitchener was sold. For a time, Electrohome remained a holding company, and then in 2007, it sold its trademarks and in 2008 the corporation's shares were cancelled and delisted.

Credits and References:

1) Jim Thoreson <jimthoreson(at)>
3) Electrohome
4) Air Traffic Detection Corps

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Aug 30/10