Friday, January 19, 2018

The First Police Radio Communication System

Policing has been around for a long time but it wasn't until radio was introduced that it became the most important tool for the cop on the beat.  There are some studies that show that many officers prefer their radio to their service revolver.

Radio communications began shortly after Marconi’s first successful radio experiments in 1896.  Early on, radio communications, or wireless as it was known back then, was used to telegraph messages from ship to shore using spark transmitters.

Detroit Base Station Equipment
The first commercial broadcast [KDKA Philadelphia] was in late 1919, 1920 saw an explosive rise in broadcast transmitters being installed across the country as radio caught the wildfire. Of course it wouldn’t be long before someone in law enforcement would see wireless applicable to his or her line of work - a weapon of sorts to combat crime!

Thus one individual in the Detroit Police Department was the first visionary that took action – William Rutledge. Rutledge, as Police Commissioner, was a pioneer in helping to develop police communications.  In 1921, just four years after Detroit purchased their first police automobiles, Rutledge began an unsuccessful trial and error attempt to use radio for police work.  Rutledge purchased a 500-watt Western Electric Model 1A broadcast transmitter.  The transmitter was installed by patrolman Bernard Fitzgerald and Walter Vogler, who worked on the experimental effort. The base station was installed on the second floor of the 9th precinct station in the central part of Detroit.

They tried to build receivers to work in moving police cars and couldn’t do it; they tried both voice and telegraph to no avail; receiver sensitivity was almost non-existent; and, vehicle noise interference was predominant – all led to disappointment and the eventual shutting down of the system in 1926 because of unsatisfactory operations.

The problem was installing delicate radio receivers inside vehicles. Vacuum tubes were fragile and the vehicle proved too much of a bad environment for a radio installation.  Police cars tend to have fast starts and quick stops, too much vibration and shaking for a receiver and especially vacuum tubes of that era; if the components survived then receivers could not stay tuned.  Other problems included antenna mounting, the effects of weather; and, automobile ignition noise interfering with signal reception.

And of course, regulators in Washington impeded the development of police radio in Detroit.  In 1921, the Commerce Department [no FCC at the time] authorized W8BNE for the Detroit police department on 1500 kHz, which was an Amateur radio license.  Three months later it was reclassified as an experimental station, and so on and so forth until the regulators got their act together.

Call Sign
Frequency [kHz]
Limited Commercial

Both failure and success came from within the Detroit Police Department.  Radio mechanics [as they were called at the time] in Detroit were eventually able to construct a radio set that could stand the jolting it got from the vehicle as well as mitigating automobile noise interference.

Robert Batts, an engineering student at Purdue, in 1927 had a summer job working in a downtown Detroit radio parts store.  He assisted their customers in building broadcast radio sets.  Even though RCA and others were selling radios, people were still constructing radios from kits. Batts also had a pick-up truck that had a receiver and a loop antenna that he used to track down interference; thus using radio in a vehicle.  He was definitely interested in radio and was pursuing a career in this field.

One of Batt’s cousins and customer was Kenneth Cox, a Detroit motorcycle patrolman. They struck up a friendship based on discussions on how to make receivers work in police cars. When Batts went back to Purdue that fall, he and Cox continued to communicate their radio designs by mail. Cox knew he could make radios work in police cars and built a model wrapped up in foam rubber based on their collaborative work. Cox then went to Rutledge to convince him that the department should make another run at it, and demonstrated by dropping his prototype receiver on the floor, turning it on, showing that it still worked.

Rutledge, understanding radio’s potential role in law enforcement gave his approval. Cox enticed Batts to return to Detroit to work on the system. Batts reluctantly left Purdue, and was eventually hired as a patrolman, allowing him to be compensated for his radio work effort. He immediately began working on the new receivers.

The first 1921 base station transmitter installation downtown was deemed by Batts to be in a bad location as buildings and power lines impeded optimum operations.  He had the equipment moved to the second floor of the police station that was located on Belle Island in Detroit.  Vogler and Fitzgerald then rebuilt the station per Batts recommendations.  They converted the transmitter to utilize crystal control rather that the self-excited oscillator that was originally used. 

A guyed mast was installed on the building for the transmitting antenna. The amplitude modulated [AM] transmitter was rated at 400 watts of power.  The transmitter required 1,800 volts of plate voltage, and was powered from two motor generators. 

Batts designed a new vehicle radio receiver that was key to the technical success. 

There was several type of mobile radios built as experimentation improved performance.  The receivers had 5 or 6 tubes depending on the receiver design type; some using AC, some using DC tube types.  In time they found that the 5-tube set using DC tubes was achieving the best results.   The receiver was a three stage tuned RF unit. Copper compartments were constructed for shielding the RF section, and tuning capacitors were locked for mechanical stability and to prevent the radio operator from changing to another frequency or station. Batts understood that shielding was important to mitigate noise interference.  He also designed spark plug noise suppressors.

The receiver was initially mounted inside the back of the car’s front seat with foam rubber to minimize the inertia of the receiver’s weight to prevent shocks getting to the tubes. 

The mobile antenna initially used was a “tophat” antenna installed on the top of the car [see picture].   Batts changed this design by having the antenna woven into the fabric of the car’s roof. They experimented with both grid and wire copper antennas.
Detroit Radio Car
This required carefully installed insulators to ensure that nothing became grounded.

The vehicle receiver [mobile radio] utilized a loudspeaker as it was determined that earphone equipment was not conducive to police mobile radio application.  Batts custom built speakers as considerable loudness was needed to be clear of noise and interference.

Persistent work by Kenneth Cox and Robert Batts, and the visionary Commissioner Rutledge, led to the development of an improved radio system, especially mobile radio receivers.   

Thus, in April of 1928, the Detroit Police Department made history as the first to dispatch patrol cars regularly by radio after about nearly a decade of struggle and disappointment. Bernard Fitzgerald was its first official radio dispatcher. Detroit was successful in making receivers work inside police cars. This achievement got overnight worldwide attention.

Within eighteen months in December of 1929, the City of Cleveland was the next to go on the air.  Robert Batts, who at this point left Detroit for Indianapolis, led the City to get law enforcement to go wireless.  Kenneth Cox took a leave of absence from Detroit Police Dept. and moved to Chicago in 1929 to help them install their first police radio system. Walter Vogler succeeded Cox as Detroit’s radio mechanic.

By 1931, over 62 police departments across the country were utilizing radio in their police cars.

1928 was the year that police radio communications began. Although in primitive form, with communications being one way [dispatcher to mobile] it changed the way police conducted their business forever.   It is interesting to note that under the KOP broadcast call sign; the police department was obligated to provide programming material during the daytime. Police calls were aired to police vehicles when needed.  Providing program material must have been difficult, as live performers, musicians and singers had to be hired to fill in the days programming – the police musical band got plenty of airtime!  This shows the amount of significance that Commissioner Rutledge must have had in radio as a police tool.  Police programming content also included a listing of stolen cars as the public was involved in crime fighting.