Authorities investigating disruptions of police radios, networks during protests: report

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w2xq

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"Authorities are reportedly probing interference with police radio networks and websites that occurred during protests over the death of George Floyd that have swept the nation."

"Such disruption efforts have occurred in Minnesota, Illinois and Texas..."

 

mmckenna

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So it isn't a conspiracy?
It's not difficult to interfere with these systems. Even with encryption. "Denial of Service" attacks have been done for years on radio systems. All you need is something a bit more powerful that the transmitter you are trying to block. Even P25 trunked systems. Doesn't take any fancy equipment, doesn't take anyone running up to an officer with a cell phone.
 

Mikejo

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it used to be called "ECM" back in my Radar Day's...

Encryption or not, as stated above, all that is needed is a powerful enough transmitter on the same frequency to deny use of said frequency.

Therefore encryption would be rendered absolutely useless as well!
 

RFI-EMI-GUY

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Yeah.
If they were really wise, they wouldn't do it. Who knows what other life safety radio traffic they are screwing up. I'm 100% OK with peaceful protests, but there's a line….
I was thinking same thing. It is pointless, dangerous harassment , serves no tactical benefit, in fact it will backfire as it will result in many agencies turning on the Big E.
 

RFI-EMI-GUY

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If they're wise they'll do it with a mobile from multiple locations or somewhere other than their home. :ROFLMAO:
The technology now exists to pinpoint the location instantaneously (TDOA) or even to go back in time and track it regardless of channel. Not to bright in this day and age,
 

RFI-EMI-GUY

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it used to be called "ECM" back in my Radar Day's...

Encryption or not, as stated above, all that is needed is a powerful enough transmitter on the same frequency to deny use of said frequency.

Therefore encryption would be rendered absolutely useless as well!
Old Crow?
 

Floridarailfanning

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The technology now exists to pinpoint the location instantaneously (TDOA) or even to go back in time and track it regardless of channel. Not to bright in this day and age,
Wouldn't the TDOA Timing Advance only work for simulcast systems where multiple sites use the same frequency?
 

RFI-EMI-GUY

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Wouldn't the TDOA Timing Advance only work for simulcast systems where multiple sites use the same frequency?
It works with any emitter. Many years back SWRI developed for the military, an SDR based, portable system of receivers that are synched to to GPS and record a wide swath of radio spectrum. You could set it up in a city on rooftops and let it run. Either in real time on a target frequency, or later review all the frequencies stored and get geo-position information on every transmitter or unintentional emitter in the area.

There is now an worlwide amateur version of that in the HF bands that you can use through a web interface.
 

mmckenna

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Wouldn't the TDOA Timing Advance only work for simulcast systems where multiple sites use the same frequency?
Depends on how they are doing it. If they were just using the simulcast system, then yes, but usually the sites are big enough that picking up a pip-squeak radio from enough locations to get an accurate fix would be difficult.

There are systems that can be deployed that link over a network. High end SDR's with GPS timing and good antenna at the right locations can nail it immediately.

But finding the individual holding the radio would be challenging in a large crowd of protesters.

At which point I refer back to the post I made a few weeks ago about stopping rogue transmitters. FCC should require that all radios imported into the country have a very small scuttling charge on the CPU. Some automagical way of triggering it when it shows up where it's not supposed to. Not to hurt the person, but to permanently render the radio inoperable.

No, such a thing doesn't exist. But it should. Maybe I'm kidding, maybe I'm not….
 

techman210

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Personally, I’m waiting to see if the reverse comes true.

If you’ve ever been near a presidential convoy, notice how your cell phone goes dead for a few minutes?

We’ll see in the future if the FRS, GMRS, MURS, ISM 900 2400 and 5300-5800 MHz bands - maybe even CB becomes unusable during riots. Also, cellphone and satellite phone frequencies may be locally unavailable with federal approval.

That’s not all that hard to accomplish.

As others have pointed out, you don’t have to overwhelm receivers with power, just something to disrupt CTCSS/DCS or to hold receivers open with noise to annoy users or drain batteries by opening the squelch with a high noise floor. This is 1970’s technology. Not hard to accomplish.

Fast “find and jam” jammers looking for strong local signals outside of “protected bands” have been around for a very long time. So “preppers” and others thinking that their 139 MHz “secret” radio channel won’t be immune from interception and electronic counter measures are misinformed.
 

Floridarailfanning

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At which point I refer back to the post I made a few weeks ago about stopping rogue transmitters. FCC should require that all radios imported into the country have a very small scuttling charge on the CPU. Some automagical way of triggering it when it shows up where it's not supposed to. Not to hurt the person, but to permanently render the radio inoperable.
There's an idea. . . Similar to the "Self Destruct" systems that some military radar and avionics units have built-in.
If you’ve ever been near a presidential convoy, notice how your cell phone goes dead for a few minutes?

We’ll see in the future if the FRS, GMRS, MURS, ISM 900 2400 and 5300-5800 MHz bands - maybe even CB becomes unusable during riots. Also, cellphone and satellite phone frequencies may be locally unavailable with federal approval.
L3/Harris have been behind a number of mobile systems like the Hailstorm which are capable of jamming and interfering with cell phones and other consumer electronics and I'm sure they have LMR jamming options as well.
 

RFI-EMI-GUY

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"But finding the individual holding the radio would be challenging in a large crowd of protesters. "

Not if the location is tracked over time and you can place that individual near a CCTV camera. Or in real time and send someone into the crowd to find him. I am told TDOA can resolve 50 feet.

I once had to track what turned out to be a local oscillator in a Motorola Mostar radiating at around 808 MHz. I was in a helicopter, with gear had a guy working on the ground in a car. We found a truck with that radio in 15 or 20 minutes. I had spent weeks looking for what turned out to be a defect in hundreds of radios running around in south Florida.

After that discovery, I parked at the busiest intersection in Broward county with my spoectrum analyser taking note of all the commercial vehicles rolling by with a Mostar.

Moto factory said the radios "met FCC specs", I say BS. They stopped making them and I don't think you will find one today. Probably crushed because the SMR owner those radios roamed on was not happy to turn off a control channel.
 
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