Police Radio

[D.J.J. Ring, Jr.]

The Ghostly "One Way" Radio That Changed History, And The Glass Wall That Named It! 📻🚨🚔

On June 16, 1931, the city of Cincinnati, Ohio, flipped the switch on a piece of technology that completely revolutionized public safety and mobile communications history: the birth of "Station X."  

​Before that morning, a police officer out on patrol was essentially on an island. Officers out on their beats or in their cars had to check in exactly once per hour using physical telephone call boxes scattered around the city. If a serious emergency or a robbery occurred at 10:05 AM, a patrolling cop wouldn't hear a single whisper about it until their scheduled call at 11:00 AM.  

​That all changed when Cincinnati brought a brand new, 500 watt AM transmitter online under the callsign WKDU, remotely controlled from a hub in the basement of City Hall.  

The initial setup was a massive engineering undertaking for its time. Technicians constructed a heavy five wire cage "T" type antenna to throw the signal, and 51 police cruisers were outfitted with specialized AM receivers.  

​The fascinating catch? This was a strictly one-way street.  

​Because mobile transmitters were still far too bulky, heavy, and power hungry to fit into a 1931 automobile, the patrol cars could only receive messages. The receivers themselves were massive tube units powered by heavy 135-volt "B" batteries tucked away in the vehicles.

  

​A dispatcher would read a call over the microphone, and the cruisers would race to the scene. However, once the officers arrived or resolved the issue, they still had to hunt down a physical telephone box to call headquarters and confirm receipt. It would take another 11 years, until 1942, before mobile technology shrunk down enough for the city to install true two way radios in their fleet.  

​As for the name "Station X," the local lore is beautifully split. One story says a police major came up with it while helping his daughter with her algebra homework, viewing the mysterious power of over the air voice transmission as the ultimate "unknown variable." 

The more hilarious office rumor claimed that the new dispatch center featured a giant, pristine plate glass partition that hurried operators kept accidentally walking into, until someone slapped a massive "X" made of tape across the middle of the glass, cementing the nickname for decades.

​The experiment was an instant triumph. Within two years, Station X was handling emergency dispatching for 25 surrounding municipalities across six counties for free. It caught the attention of the entire nation, prompting police delegations from major hubs like Chicago to travel down just to study how a single radio room could hold its finger on the pulse of nearly a million people.  

#RadioHistory #WirelessHistory #VintageTech #StationX #PublicSafetyHistory

[Mike Hutchins]

Didn't they operate somewhere close to the present 160m amateur band ? -- or is my memory playing games again ?

73 de Mike, zl1mh.

On 23/06/2026 10:59 pm, D.J.J. Ring, Jr. wrote:

The Ghostly "One Way" Radio That Changed History, And The Glass Wall That Named It! 📻🚨🚔

40mail.gmail.com.

[Radio KH6O]

Yes Mike, your're correct!, LAPD HQ transmitted on 1730 Kc and the officers received the transmissions on their AM band car radios (as did the general public).

Here's the most definitive site on the history of LAPD communications (but for some reason, only Page 2 is available right now):

https://www.qsl.net/n6uru/kma367-2.htm  (LAPD's callsign was KMA-367)

Jeff KH6O

[Mike Hutchins]

Thanks Jeff....interesting (and reassuring !). Like they say, those were
the days.

73 de Mike, zl1mh.