The KA1RCI Network
The Big Blue Beast - 1995 GMC Suburban
Fun and Excitement doing some RFI Direction Finding
More than 30 years ago, while working on different antenna projects in my backyard with my father Bill KA1VKD, I would wonder to myself, “Just how does Uncle Charlie (1) pinpoint my signal out of the RF chaos floating in the ether?”
Now, years later after gaining some experience in the art of tracking RF signals, here I was, helping Richard Andreano K3OQH of the Rhode Island Emergency Management Agency (2) track down that one small signal.
The issue described in this story started in late July, 2007 when the Warwick, RI (3) Police Department noticed that its normal radio communications was being disrupted by unlawful and malicious transmissions to its dispatch repeater system.
Warwick PD Director of Administration, Major Thomas Nye and Col. Stephen McCartney were puzzled about how these transmissions were being made. Had one of their police radios been stolen? Could there be some odd atmospheric condition taking place that was causing interference from a distant station? Or were they truly faced with someone deliberately disrupting police operations?
The police were able to rule out any missing or stolen radios, and after a few more illicit transmissions, were also able to rule out atmospheric conditions. Col. McCartney needed to identify and stop these transmissions to keep his officers and the public safe. He wanted to quickly find the individual responsible for this illegal radio work as well as to send a message that this type of activity would not be tolerated.
In this post 9/11 era, we all live with a heightened awareness of attack. Overt disruption to public safety communication in any form is an extremely dangerous offense and should be taken very seriously and dealt with appropriately.
contacted Rick, K3OQH at state EOC HQ for assistance. Warwick PD was not
equipped to track down the malicious transmissions and needed technical help
from someone experienced in Radio Direction Finding.
Lt. Paul Berry, KB1OCU of the Cumberland Fire Department, Officer Robert Chille, KB1AAW of the Warwick Police Department and Steve Hodell, KA1RCI ARRL Assistant Section Manager for RI were quickly brought together to work with Warwick PD Sgt. David DeAngelis (not a ham…yet) who was in charge of the overall investigation and Daniel Colwell, Warwick PD Communications Tech.
The Hunt Begins
With the first few phone calls organizing our effort to track down the source of these rogue transmissions, we agreed that the Warwick PD should be notified immediately that we would be in their city conducting radio surveillance. Descriptions of our vehicles including registration numbers were provided in an effort to head off any “suspicious vehicle calls” that residents might make.
Much to my chagrin however, this had exactly the opposite effect as the very first night our team began conducting surveillance my truck, a dark GMC Suburban with dark window and multiple antennas that I affectionately call the Big Blue Beast (4) and which is often mistaken for a police or secret service vehicle, was stopped by a Warwick patrol officer.
Only moments after our first planning meeting in the communications office, as I was leaving police headquarters, driving to my surveillance location, I noticed a city patrol car maneuvering thru traffic on the busy four lane undivided highway behind me. The call crackled through one of my speakers…“Vehicle stop on Rhode Island King Apple One Radio Charlie India”. He was actually pulling me over! I was able to safely pull over to the curb a few car lengths up the busy road in a driveway apron and waited for the officer to approach my truck.
“Do you have a scanner in there with you?” the officer asked. I had to bite my lip to keep from grinning, instead made the prudent decision to simply answer, “Yes Sir” instead of trying to explain the difference between the thousands of dollars of radio communication gear professionally installed in a “Troy Products” Console (5) obviously visible in my truck and a mere scanner.
It was easy to anticipate the officer’s next question. “Did you hear me make the call on your truck on the police frequency?” Again I simply answered, “Yes Sir”.
Then the fun really started when he asked for my driver’s license, registration, and proof of insurance. Instinctively, I pulled my ID holder out of my pocket and produced my RI Driver’s license, however the very observant patrol officer also noticed my RI Pistol Permit, allowing me to carry concealed firearms.
I was unprepared for the next question…“Do you have any weapons in the truck?” Again, without thinking, I started to look down and then reached back to see if I had my sidearm with me.
When I looked up, there were several more patrol cars and officers visible in my rear view mirror and I started to think that I wouldn’t be doing any radio direction hunting that night. In some apparent miscommunication, the message this patrol officer received was to “be on the look out” for a dark colored GMC truck with many antennas and RI registration KA1RCI. Fortunately, Sergeant DeAngelis and Officer Chille (a ham) both heard the radio dispatch about my truck and quickly came to my rescue.
Soon, with this preliminary excitement behind us, the assembled teams of Police
and Fire Communications Officers and Amateur Radio Operators formally started to
DF the malicious transmissions on Wednesday evening
Several observations were made about the signal characteristics during these transmissions and in later review of the transmission recordings which identified the following:
During these transmissions, there were references made to specific streets in
the north end of the city. Calls to patrol cars were made, "’P-28, where are you
going?" These designations used would be the unit number visible on the side of
the vehicle but not the radio call sign or signal assigned to the officer
patrolling in that area. This observation directed the initial efforts to setup
(Radio Frequency) DF
(Direction Finding) teams to the
Using multiple UHF receivers with directional antennas and signal
attenuators, three preliminary wide area locations in an approximate one mile
After a few hours of monitoring, the suspect signal appeared on the air again
and was quickly vectored with directional antennas to be in the area of
The team immediately moved to set up three new locations, closer to the triangulated signal position. While moving towards the pirate transmitter area,
detected a strong signal on the receiver in my truck along
Quickly switching in more attenuation, I drove down
Stealth Mode engaged
We were all aware that the individuals making these transmissions had to have at
least some fundamental radio knowledge and they could possibly even be
monitoring our conversations while we were trying to coordinate our activities.
Our teams were already using Amateur radios on a two meter simplex frequency to
keep in touch with one another and we also requested that the dispatchers, and
any officers assisting in the investigation, not say anything on the main
Using these new 800 MHz radios with their ability to provide secure digital communications, they played an important part in our overall process and utilizing them was truly a great model of interagency cooperation and a collaborative effort with volunteers from the Amateur radio community.
The 800 MHz radios enabled our team to communicate with the dispatchers back at headquarters who turned out to be a very valuable resource. Because the pirate radio did not have the appropriate digital ID (squawk), like the Warwick PD radios which would display on the dispatchers console, the dispatchers could immediately notify our team using the 800 MHz radios every time that the illegal transmitter was active.
Once it was safe to conduct one of these fake incidents (officers were not out
responding to actual calls etc.)
Each of the Amateur radio operators were poised and ready with their directional antennas, attenuators, two meter radios, UHF police receivers, and 800 MHz handhelds. Goodness! We really did look like geeks with all that stuff!
few weeks more of this stake out activity followed; setting up nightly
surveillance, waiting for the unlawful transmissions, baiting the kids into
talking and then triangulating on the signals source, narrowing the target area
considerably each time. The team also received information from patrol officers,
Time to “Kick in the Door”
That night, after regular work hours, we all gathered again at the suspect location, setting up all of our radio direction finding gear and waited. Shortly after one of the younger kids that we had identified as “10-4 radio check” began making transmissions on the Police Department repeater input frequency and we were able to confirm that the malicious and unlawful transmission was coming from the suspected residence.
The hair on the back of my neck stood up as the call came over the radio… “It’s time to kick in the door”. Five cruisers, two unmarked cruisers, and the Big Blue Beast rushed the house.
It was a scene right out of the TV show, “COPS” with the officers shouting “POLICE -- SEARCH WARRANT”, entering the suspect residence and grabbing everyone in the house. The kids had pulled the microphone off the radio and threw it under the couch as the police stormed in. They tried to claim that the radio was just a scanner and was not capable of transmitting.
police secured the house,
I was also able to confirm that the suspect signal was coming from less than 100 feet of my truck parked directly in front of the house by using a 110 dB attenuator in line with my mobile receiver.
With the house secure and the suspects in police custody, the Sergeant asked our team to enter the home to identify and list all the radio equipment including power supply, antenna, and computer with the programming cable used to enter the Warwick Police frequencies etc. We inventoried everything and loaded it all into the Big Blue Beast for transport back the headquarters. It would later be used as evidence.
Our team of
“Radio Geeks” as
(2) http://www.riema.ri.gov/ - Domestic Preparedness Program Assistant
(3) http://www.warwickri.gov/ http://www.warwickpd.org/
(4) KA1RCI’s GMC Suburban – RF on 28, 52, 144, 220, 440 and 900 MHz
(6) The XTS 2500 portable radio is Motorola's high-performance, small-sized, digital two-way radio.
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