(Part 1 of 3)
The story below focuses on the suburban Chicago area. Very similar programs took place in other metro areas like New York, Boston and Los Angeles.
When I first started to be interested on police communications in the late 1960’s and early 1970’s police and fire operations were mostly on VHF high band. My local police were on 155.130, and my old Regency scanner rarely moved off this channel due to the dozen or more towns in our area that used it as well as the Wisconsin, Indiana and Michigan users I could hear often. Eventually my hometown moved to the new “T-Band” channels and I needed to get a new scanner.
2024 is the 50th anniversary of the startup of many of the numbered T-Band Networks set up in the suburban Cook County area surrounding Chicago. The Network Numbers ranged from 1 to 24 officially, with 5 more unofficially numbered ones in the border areas or adjacent counties. Most were on UHF T-Band from 470 to 476 MHz. (See below for the breakdown). The program originated in the early 70’s and was mostly completed by the end of 1974. The Network Numbers survive even today as the common name of some of the channels used by agencies, even when they have moved to other systems, mostly StarCom21.
In the early 1970’s the police departments in the suburbs of Chicago were almost universally using VHF High Band (mostly from 154 thru 159 MHz.), and usually simplex. There were a few outliers here and there, but the vast majority were sharing about a dozen frequencies. Then, as it is now, Chicago’s suburbs tend to be fairly small, these days from a few thousand up to about 50 thousand for the most part. Back then they were much smaller except for the close-in/boxed in and matured towns like Park Ridge, Winnetka, Berwyn and Riverside. Around the edges were some towns that were just starting to become recognized as suburbs, towns like Aurora, Elgin, Joliet and Waukegan. These towns were more like independent cities of their own before suburban sprawl grew to envelop them.
Chicago itself had recently moved to 460 MHz. UHF from VHF channels, some of those VHF channels were re-farmed out to some of the suburbs. Ny dad was heavily involved in the CPD UHF transition, he worked for Illinois Bell Telephone and was the project manager for the then new communications system and helped redraw some of the District boundaries to match the telephone exchange boundaries to make it easier and cheaper to route calls to the proper desk based on the exchange the call originated from.
Cook County itself used VHF high band as well for the Sheriff’s Police. Originally on 159.090 they soon thereafter established new North (155.595) and South (155.535) repeaters and a couple other channels for their use. Neither Cook County Sheriff nor Chicago PD were considered for T-Band channels at the time.
During the 1950’s and 1960’s post-war Chicagoland suburbs grew exponentially, and this didn’t really stop in the 70’s. Some of the further out suburbs like Plainfield or Elgin are still growing quickly today. With no end of growth in sight, police departments communications needs grew as well. With upwards of 20 growing towns sharing a single channel, the channels were overwhelmed. Sooner or later this problem would come home to roost. That day was October 1, 1972. Police Officer Anthony Raymond of the Hillside police department made what he presumed would be a routine traffic stop on a car entering an expressway. What he couldn’t know was that the occupants of that car had just committed an armed robbery.
Somehow, they got the drop on Officer Raymond, kidnapped him, then strangled and stabbed him to death. His body was eventually buried in a field in northern Wisconsin, not to be found for almost a year. Over the next year after his body was found suspects were identified and arrested for his murder as well as another, of an 18-year-old girl found buried near the officer’s body.
One of the reasons he was not found to be missing as quickly as one would expect was that he could not get thru to dispatch on his radio. The simplex radio channel (155.490) that Hillside shared with more than a dozen other towns in the area was so busy that most traffic stops and other “routine” radio traffic we take for granted today just didn’t happen. When they were called in, they were often stepped on by other towns sharing the channel. Too many towns and not enough channels made a dangerous combination, and that cost Anthony Raymond his life. He was 25 and been on the job for 3 years. He had 2 small sons and a wife at home.
While discussions of what to do about the situation in this area, as well as other metropolitan areas around the country, had been happening for a while, this was the spark that lit a fire under the feet of politicians, engineers and police officials. The police communications issue had to be addressed, and it needed to happen NOW.
As of 1972 about a dozen VHF channels, like 155.190 (35 suburbs, with a combined population of about 465,000) or 155.490 (17 suburbs, with over 300,000 people) were used by the 120+ towns. Some of those channels were also heavily used by agencies in other counties in the area. Only a couple were already using repeaters, so in order to make the rest repeaters more scarce VHF channels would be needed. Add to that, distant stations were commonly heard from all over the Midwest, especially on summer evenings when “Skip” conditions were common.
Concurrently the federal government had a grant program called Law Enforcement Assistance (LEA). These grants were to be used to modernize police procedures and equipment. The studies funded by these grants proved the need for a massive increase in the available frequency spectrum for police communications. These grants also eventually paid for much of the new radio equipment needed.
Also, during this time, partly as a result of all these discussions, the FCC reallocated UHF TV channels 14 thru 20 (470 thru 512 MHz.) in the largest metro areas to land mobile use on a shared basis with the existing TV stations, with a portion reserved for public safety use. This is commonly referred to as “T-Band” or “Television Sharing Band”. The ten largest metro areas were allocated one or more 6 MHz. segments, corresponding to TV channels based on need and availability so as not to interfere with existing TV stations. The Chicago area was allocated TV Channels 14 (470-476 MHz.) and 15 (476-482 MHz.) but only Channel 14 was used at first due to some “Safe Harbor” issues with Channel 15 and TV stations using it in the Midwest. Channel 15 was eventually released but well after the first systems were established.
In 1972 the Illinois Institute of Technology (IIT) published an exhaustive study of police communications in Cook County, Illinois. While dominated by the City of Chicago, Cook County is also home to over 120 suburbs, almost all of which had their own police departments and most of them also had their own dispatchers, while a few were dispatched by neighboring towns.
Each 6 MHz. TV channel (Channel 14 in the Chicago area) was split into 2 segments. The lower 3 MHz. (470 to 473 on Channel 14) was reserved for repeater outputs or base operations and the higher 3 MHz. (473 to 476) was reserved for mobile use. This was a relatively orderly way to set up repeater pairs, compared to the VHF high band which had no specific relationship between the repeater output and input. 3 MHz. separation of repeater and mobile inputs was chosen as it is half of the available spectrum. Decades later when 90 MHz. of spectrum in the 800 MHz. band was set aside for land mobile and cellular use the inputs were set at 45 Mhz. apart for the same practical reason.
From there individual channels were set up at 25 KHz. apart but on the “odd” channels. Instead of frequencies like 470.100 and 470.125, the channels were offset by 12.5 KHz. so that the channels would be 470.1125 and 470.1375 and so on. Why this was done is anyone’s guess. A couple decades later the channels in-between would be authorized for use to effectively double the available channels.
(Continued in Part 2)
The story below focuses on the suburban Chicago area. Very similar programs took place in other metro areas like New York, Boston and Los Angeles.
When I first started to be interested on police communications in the late 1960’s and early 1970’s police and fire operations were mostly on VHF high band. My local police were on 155.130, and my old Regency scanner rarely moved off this channel due to the dozen or more towns in our area that used it as well as the Wisconsin, Indiana and Michigan users I could hear often. Eventually my hometown moved to the new “T-Band” channels and I needed to get a new scanner.
2024 is the 50th anniversary of the startup of many of the numbered T-Band Networks set up in the suburban Cook County area surrounding Chicago. The Network Numbers ranged from 1 to 24 officially, with 5 more unofficially numbered ones in the border areas or adjacent counties. Most were on UHF T-Band from 470 to 476 MHz. (See below for the breakdown). The program originated in the early 70’s and was mostly completed by the end of 1974. The Network Numbers survive even today as the common name of some of the channels used by agencies, even when they have moved to other systems, mostly StarCom21.
In the early 1970’s the police departments in the suburbs of Chicago were almost universally using VHF High Band (mostly from 154 thru 159 MHz.), and usually simplex. There were a few outliers here and there, but the vast majority were sharing about a dozen frequencies. Then, as it is now, Chicago’s suburbs tend to be fairly small, these days from a few thousand up to about 50 thousand for the most part. Back then they were much smaller except for the close-in/boxed in and matured towns like Park Ridge, Winnetka, Berwyn and Riverside. Around the edges were some towns that were just starting to become recognized as suburbs, towns like Aurora, Elgin, Joliet and Waukegan. These towns were more like independent cities of their own before suburban sprawl grew to envelop them.
Chicago itself had recently moved to 460 MHz. UHF from VHF channels, some of those VHF channels were re-farmed out to some of the suburbs. Ny dad was heavily involved in the CPD UHF transition, he worked for Illinois Bell Telephone and was the project manager for the then new communications system and helped redraw some of the District boundaries to match the telephone exchange boundaries to make it easier and cheaper to route calls to the proper desk based on the exchange the call originated from.
Cook County itself used VHF high band as well for the Sheriff’s Police. Originally on 159.090 they soon thereafter established new North (155.595) and South (155.535) repeaters and a couple other channels for their use. Neither Cook County Sheriff nor Chicago PD were considered for T-Band channels at the time.
During the 1950’s and 1960’s post-war Chicagoland suburbs grew exponentially, and this didn’t really stop in the 70’s. Some of the further out suburbs like Plainfield or Elgin are still growing quickly today. With no end of growth in sight, police departments communications needs grew as well. With upwards of 20 growing towns sharing a single channel, the channels were overwhelmed. Sooner or later this problem would come home to roost. That day was October 1, 1972. Police Officer Anthony Raymond of the Hillside police department made what he presumed would be a routine traffic stop on a car entering an expressway. What he couldn’t know was that the occupants of that car had just committed an armed robbery.
Somehow, they got the drop on Officer Raymond, kidnapped him, then strangled and stabbed him to death. His body was eventually buried in a field in northern Wisconsin, not to be found for almost a year. Over the next year after his body was found suspects were identified and arrested for his murder as well as another, of an 18-year-old girl found buried near the officer’s body.
One of the reasons he was not found to be missing as quickly as one would expect was that he could not get thru to dispatch on his radio. The simplex radio channel (155.490) that Hillside shared with more than a dozen other towns in the area was so busy that most traffic stops and other “routine” radio traffic we take for granted today just didn’t happen. When they were called in, they were often stepped on by other towns sharing the channel. Too many towns and not enough channels made a dangerous combination, and that cost Anthony Raymond his life. He was 25 and been on the job for 3 years. He had 2 small sons and a wife at home.
While discussions of what to do about the situation in this area, as well as other metropolitan areas around the country, had been happening for a while, this was the spark that lit a fire under the feet of politicians, engineers and police officials. The police communications issue had to be addressed, and it needed to happen NOW.
As of 1972 about a dozen VHF channels, like 155.190 (35 suburbs, with a combined population of about 465,000) or 155.490 (17 suburbs, with over 300,000 people) were used by the 120+ towns. Some of those channels were also heavily used by agencies in other counties in the area. Only a couple were already using repeaters, so in order to make the rest repeaters more scarce VHF channels would be needed. Add to that, distant stations were commonly heard from all over the Midwest, especially on summer evenings when “Skip” conditions were common.
Concurrently the federal government had a grant program called Law Enforcement Assistance (LEA). These grants were to be used to modernize police procedures and equipment. The studies funded by these grants proved the need for a massive increase in the available frequency spectrum for police communications. These grants also eventually paid for much of the new radio equipment needed.
Also, during this time, partly as a result of all these discussions, the FCC reallocated UHF TV channels 14 thru 20 (470 thru 512 MHz.) in the largest metro areas to land mobile use on a shared basis with the existing TV stations, with a portion reserved for public safety use. This is commonly referred to as “T-Band” or “Television Sharing Band”. The ten largest metro areas were allocated one or more 6 MHz. segments, corresponding to TV channels based on need and availability so as not to interfere with existing TV stations. The Chicago area was allocated TV Channels 14 (470-476 MHz.) and 15 (476-482 MHz.) but only Channel 14 was used at first due to some “Safe Harbor” issues with Channel 15 and TV stations using it in the Midwest. Channel 15 was eventually released but well after the first systems were established.
In 1972 the Illinois Institute of Technology (IIT) published an exhaustive study of police communications in Cook County, Illinois. While dominated by the City of Chicago, Cook County is also home to over 120 suburbs, almost all of which had their own police departments and most of them also had their own dispatchers, while a few were dispatched by neighboring towns.
Each 6 MHz. TV channel (Channel 14 in the Chicago area) was split into 2 segments. The lower 3 MHz. (470 to 473 on Channel 14) was reserved for repeater outputs or base operations and the higher 3 MHz. (473 to 476) was reserved for mobile use. This was a relatively orderly way to set up repeater pairs, compared to the VHF high band which had no specific relationship between the repeater output and input. 3 MHz. separation of repeater and mobile inputs was chosen as it is half of the available spectrum. Decades later when 90 MHz. of spectrum in the 800 MHz. band was set aside for land mobile and cellular use the inputs were set at 45 Mhz. apart for the same practical reason.
From there individual channels were set up at 25 KHz. apart but on the “odd” channels. Instead of frequencies like 470.100 and 470.125, the channels were offset by 12.5 KHz. so that the channels would be 470.1125 and 470.1375 and so on. Why this was done is anyone’s guess. A couple decades later the channels in-between would be authorized for use to effectively double the available channels.
(Continued in Part 2)
