St. Paul, MN, City Radio System, 1951

ofd8001

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You wonder what those "old-timers" would have to say about the current system?

I remember childhood days when Minneapolis Fire was using VHF Low and the Police were on VHF High.
 

KA0XR

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Cool post! Old timers would no doubt scoff at the current system based on the fact the city population was probably greater at that time yet still managed to communicate.

Does anyone know if Minneapolis police started out on VHF low band before going to high and then at some point to 460 MHz?
 

JASII

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...Does anyone know if Minneapolis police started out on VHF low band before going to high and then at some point to 460 MHz?
The earliest information I have run across was that Minneapolis Police calls came across WCCO 830 radio.

Similarly, Saint Paul Police call came across KSTP 1500 radio.

Neither of those, obviously, were two-way radio, yet.

Hibbing Police were the first to get police radio, according to some history I found. It, too, was one-way radio. The Chief of Police ordered the equipment removed after a couple of years. He declared that radio would never be an effective tool for law enforcement!

A big portion of the state was on VHF low-band years ago. It was 45 mHz. All carrier squelch.

My best guess is that they were, indeed, on VHF low band, originally. Maybe 39 mHz.

Eventually, they switched to VHF high band. When the Montgomery Report came out, they recommended four agencies switch to the "new" UHF band. They were Minneapolis Police, Saint Paul Police, Airport Police and University of Minnesota Police on 460.xxx. The other 460.xxxs were not for dispatch, but other uses. That would include Hennepin County Sheriff's Office and Ramsey County Sheriff's Office 460.xxx assignments.



 

lenk911

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I began fixing two way radios in Minnesota in 1959. At that time, the state was checkerboarded between low band and VHF. Wisconsin was all low band except in the far south. Many agencies had WWII surplus non tactical radios--Motorola Turkey Roasters and GE 7thMOs (Also called turkey roasters) on 39 MHZ and GE Pre-Progress Line's in the VHF band.

The 1963 FCC narrow banding mandate killed all that. Other than Duluth, NW Minnesota and the Patrol went to the VHF band. The Patrol switched from 1700 KHZ to 42.82/42.66 in the 1949-1951 era. Their 1700 KHZ tower was a modified KSTP 1500 KHz AM tower reinstalled at the SE corner of I-35W and I-694. What also killed low band was the 1957-1960 sunspot cycle. It was the highest of recorded history. A 10-watt TV station from Germany would wipe out the Patrol's communications on 42 MHZ for days.

For St Paul PD, in the early 1950's Hubbard Broadcasting brokered a deal with the Fred Link Company, an early manufacturer of two way radios. Tough radio to keep going and the company succumbed early in radio history. I think Saint Paul was their only customer.

The Montgomery report you mentioned was the result of the 1970's law enforcement assistance act federal grant (LEAA) program. Most of the Upper Midwest switched to the VHF band from that grant. Big scandal in Wisconsin over the use of funds. 60 Minutes involved and I was subpoenaed to testify before a congressional subcommittee that convened in Hudson in 1972.

The Patrol didn't switch to VHF until the early 1980's.
 

stmills

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I came across this article a while back that talks about Edina's history of radios- and how they operated when Minneapolis was dispatching calls for them. One way dispatch was used until 1955 when two way finally arrived. I believe Minneapolis was on the 39 mhz chunk but i can not find a good reference to it. I know Hennepin dispatch used 39.9 mhz but if memory of what I learned on this is correct Minneapolis and Hennepin were on different frequencies.
history of Edina Police Dispatch
 

JASII

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Some of the first Police Call Radio Directories that I bought years ago still showed some legacy VHF low band frequencies.
 

KA0XR

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I began fixing two way radios in Minnesota in 1959. At that time, the state was checkerboarded between low band and VHF. Wisconsin was all low band except in the far south. Many agencies had WWII surplus non tactical radios--Motorola Turkey Roasters and GE 7thMOs (Also called turkey roasters) on 39 MHZ and GE Pre-Progress Line's in the VHF band.

The 1963 FCC narrow banding mandate killed all that. Other than Duluth, NW Minnesota and the Patrol went to the VHF band. The Patrol switched from 1700 KHZ to 42.82/42.66 in the 1949-1951 era. Their 1700 KHZ tower was a modified KSTP 1500 KHz AM tower reinstalled at the SE corner of I-35W and I-694. What also killed low band was the 1957-1960 sunspot cycle. It was the highest of recorded history. A 10-watt TV station from Germany would wipe out the Patrol's communications on 42 MHZ for days.

For St Paul PD, in the early 1950's Hubbard Broadcasting brokered a deal with the Fred Link Company, an early manufacturer of two way radios. Tough radio to keep going and the company succumbed early in radio history. I think Saint Paul was their only customer.

The Montgomery report you mentioned was the result of the 1970's law enforcement assistance act federal grant (LEAA) program. Most of the Upper Midwest switched to the VHF band from that grant. Big scandal in Wisconsin over the use of funds. 60 Minutes involved and I was subpoenaed to testify before a congressional subcommittee that convened in Hudson in 1972.

The Patrol didn't switch to VHF until the early 1980's.

Really cool information and history! Thanks for sharing.

To modify a 1500 KHz tower for 1700KHz did they just lop off a few feet to make it resonant? I remember my Dad saying he could tune in the Minneapolis police on the AM radio so the 1955 conversion date to two way sounds right on.

I bet the late 1950's sunspot cycle must have been quite the troublesome eye opener and revelation for 2 way lowband police radio nationwide if a 10 watt TV from thousands of miles away could wipe out radios here. How much power would these low band base station radios actually run compared to the VHF High Band stations that came later? I saw references in an old 1963 publication about the Patrol 42 MHz base stations running 3,000 watts which seems excessive if the goal is to also hear the mobile station. If this is true no wonder there were skip issues.

It would be fun to have a sunspot cycle like the late 50's for 6 Meter enthusiasts. I wonder if the MUF and intensity of the openings during the late 50's would have allowed for 6 meter FM DX had surplus equipment been available to hams at that time.

I think I looked at the mentioned Montgomery Report years ago at the MN Historical Society if it was published in 1971. Most of what was written in this report came to fruition in terms of frequency use by the counties. I also at some point came across a 60's era list showing all the MN county sheriff frequencies which was a mix of low band and VHF. With few exceptions the trend was high band in southern MN and lowband in northern MN but Cook and Carlton Counties were on HB. I have a 1977 version of Police Call and most lowband activity by that time was relegated to Veterinarians and random school districts, outside of the State Patrol.

State patrol should have stopped "advancing" at VHF High Band in my opinion since they require statewide coverage and VHF worked well for 2+ decades.
 

lenk911

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At the core radio sites, usually near district offices, the 1950's era Patrol system used 10,000 Watt Motorola FMTR (Research Line) series base stations. The FCC allowed state police agencies to use that power. The big reason was a large required coverage area verses budgets and the vehicular ignition noise was horrendous. The finals tubes seemed like milk jugs that glowed florescent blue on transmit.

When noise-blankers were developed, that helped with the vehicular noise. Over time, they added filler sites of 300 and 100 watt transmitters and when I came to work for them in the late 1960's, the 10 KW stations were loafing around 1 KW. To my knowledge, Minnesota and Wyoming were the only licensees on 42.820/42.660 MHZ in North America. Signals from Wyoming told us a big storm was coming our way. Never heard any other stations on the frequencies.

The old KSTP 1500 tower was removed and less sections reinstalled at I35W and I 694. It had a 12-15" insulator at the base section so it probably was an end fed 1/4 wave and re-resonated at 1700 KHZ. The BCA operated a second 1700 KHZ station down in the Redwood Falls area and between the two, they dispatched Minnesota before the 1950's. Squads on hearing the one-way call would swing into a telephone office and communicate with the dispatcher by telephone. Summertime motorcycle officers would look for a blue light lit at the telephone offices as a signal to call-in.
 

KA0XR

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Cool history lesson! I had no idea 2 way radio operations ever used that kind of power. With 10,000 watts I suppose any base station (or other station not battling ignition noise) could hear the district's dispatcher from a great many miles away! Question is, could the troopers on the fringe of their district actually then talk back to the dispatcher with their "limited" 100 watt Motracs and ball mount whip antennas?

I suppose this has never been tried but I wonder what 10,000 watts or even 1,000 could do on 2 Meters/VHF high band, and if it would equal the radio footprint (local coverage) of what those high power lowband stations covered? If anyone is interested I posted a scan I made a while ago of the State Patrol's low band system as it appeared in the 1985 Monitor America book just before converting to high band. Obviosuly a lot of filler sites since the original design.

With Minneapolis on low band in the early days was the Hennepin County Sheriff ever on low band for primary dispatching? They still maintain a license for 45.66 MHz which I guess was once an intersystem channel for communicating 911 call information to various cities.
 

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lenk911

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Regarding: Question is, could the troopers on the fringe of their district actually then talk back to the dispatcher with their "limited" 100 watt Motracs and ball mount whip antennas?

All the dispatch centers monitored 42.66 from all the towers (30+). So for instance, the Rochester district cars in the north stations (Redwing-Northfield) would call Saint Paul if they couldn't reach Rochester etc. Saint Paul would relay back their traffic to Rochester.

Saint Paul dispatched through the main site at New Brighton (the old 1700 KHZ tower) and the remote sites at the Shakopee Scale House (by Flying Cloud Airport) and Kimball (SW of Saint Cloud). Brainerd would catch the north Saint Paul district cars and the south Duluth district cars along I-35 through Woodland (SE of Lake Mille Lacs) and also relay. Remote sites were connected back to the district dispatch center by some very long 72/75, 150, and 450 MHZ control links.

Regarding Hennepin on 39.9: I believe they switched to VHF with the 1963 narrow banding mandate. In 1966, I remember them simplex on 155.610 and 155.850 with no tone. In 1968-70, they put in the big county wide GE system that brought them up to ARMER. It was at that time they added 45.66 Intersystem as a hot line between the county and the Independent's dispatch centers. They overlaid the UHF system as part of the statewide LEAA federal inter operability grant program to intercommunicate with Minneapolis and MSP PD.
 

JASII

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Maybe there are only a few of us now that still remember the Metro-MINSEF cross-patch repeaters.

To the credit of Minneapolis ECC, they were able to bring up the cross-patch fairly quickly. The other PSAPs, not so much!

I can remember any number of times, too, when there was more then one incident using MINSEF. Say Oakdale is using MINSEF and then Minneapolis enables the cross-patch repeater. It made it a real challenge for the agencies to each use it.

The other thing I remember about the State Patrol radios on VHF high band is they ran high enough power, probably 110 watts, that if you were sitting next to them when they transmitted, that signal was strong enough to completely de-sense the Motorola radio in your own vehicle. For example, if the trooper was transmitting on 159.345 on the repeater input, you might be sitting right next to them tuned to 154.935, the repeater output, but the 159.345 was so strong that it de-sensed your receiver and you heard nothing on 154.935 Mhz.
 
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