How to spot an unmarked police car

[HantsRat]

spookly said:

I'm currently building a tetra/airwave detector. Similar to the Python or Target BlueEye.

Built using a Raspberry Pi 3, an SDR and a small LCD screen. Just need to write a python or C++ gui for it and it'll work. I can already scan the relevant frequencies and identify the uplink radio chatter, but until I create an interface I can only see it on a waterfall graph or in raw csv data files.

It isn't breaking the law as the device is incapable of decrypting the traffic, and in this instance is not even capturing encrypted data samples, it simply scans the relevant frequencies several times over 4 seconds then reports back the strongest signal found.

After calibration it should be able to tell you roughly how far the nearest active (ie. switched on) tetra mobile unit is.
I'll set it to display a dB output, but depending on results of calibration I might also create:

• a graph output
• an indicator of whether receive strength is currently rising/falling (ie. likely moving away or towards source)
• number of active channels identified (identify higher/lower number of different sources)
• approximate distance (probably fairly coarse... something like <200m, <500m, <1mile) - this will be indicative only due to lots of factors (reflection, original signal strength, etc)

I already had the RPi 3, and the screen. So total cost is about £25 for a decent shielded SDR. If you wanted to buy all the stuff required on the cheap then you'd be looking at about £60-£70.

I then plan to add a Bluetooth media player, GPS speedo, and possibly add two remote HD cameras to make a dashcam. Will also put it into a case and maybe add battery/ups power.

I expect it to be reasonably useless in urban areas, especially leaving home as I live by a fire stations, and you are never very far from an ambulance, policeman, pcso or fire engine. But it should still show rough distance and whether sources are getting closer or further away.

Edited by spookly on Friday 17th March 10:52

What's the point when it will just go off for all masts, hatos, fire engines, ambulances. You'd soon get fed up and turn it off.

Not to mention that tetra is now on it's way out and being replaced soon.

[GloriaGTI]

Not sure if this has been mentioned already...

A good sign is the amount of weight over the rear axle from a loaded boot.

Last summer, I had a silver Octavia VRS pull along side me as I was hooning on to the M27 E'bound at J3 on my bike.

One thing I noticed, after I'd got over the initial shock of a police vehicle matching my rather excessive speed and then proceeding to continue with his journey, was how low the car was sitting over the rear axle.

There were a number of Octavia VRS in South Hants last year, although now they seem to be using BMW 3 series with dark tints, again with a lot of weight in the boot.

So another thing to look out for

[HantsRat]

GloriaGTI said:

Not sure if this has been mentioned already...

A good sign is the amount of weight over the rear axle from a loaded boot.

Last summer, I had a silver Octavia VRS pull along side me as I was hooning on to the M27 E'bound at J3 on my bike.

One thing I noticed, after I'd got over the initial shock of a police vehicle matching my rather excessive speed and then proceeding to continue with his journey, was how low the car was sitting over the rear axle.

There were a number of Octavia VRS in South Hants last year, although now they seem to be using BMW 3 series with dark tints, again with a lot of weight in the boot.

So another thing to look out for

Lot's of VRS's about still in hants. As well as 3 series, also 5 series, fords and volvos plus many others are about.

[ashleyman]

Surrey have an Audi S3 blasting around...

Seen it a couple times. A Ferrari California overtook me like I was standing still a while back and then proceeded to undertake/overtake everything in front of me. A couple minutes later the S3, followed by a couple other cars went past. I later found out they were chasing the Ferrari!

The best one was a Corsa with what looked like 4 or 5 lads in blasting down the M25 one evening. I was already at 75 in L3 (I was overtaking a car in L2) and this thing came up behind me and was flashing me to move over. I eventually moved back to L1, then waited for them to pick up the speed in order to overtake (it took a while and they're still hogging L3) eventually they went past and the speed kept climbing. The Audi S3 was in L1 when I overtook it a few moments earlier and I assume had seen everything that had happened as it pulled out to L3 and came blasting past me. I was just waiting to see the lights come on behind the Corsa. My wife & I laughed so hard at these lads getting pulled.

[spookly]

HantsRat said:

What's the point when it will just go off for all masts, hatos, fire engines, ambulances. You'd soon get fed up and turn it off.

Not to mention that tetra is now on it's way out and being replaced soon.

Because you are wrong. Uplink and downlink frequencies are different. It will only scan in the frequency used by the tetra mobile radios, not the network masts. Same as the way Python and Target BlueEye work.

I'm doing it as I already have all the stuff for it, and programming such a simple thing is child's play.

They have been planning turning off Tetra for some time but still haven't, and still have no firm date. 4G networks/LTE are missing some of the key requirements that they have, and surprisingly most mobile telcos don't want the expense of adding them.... and if they did they'd end up with very expensive LTE, just like they had expensive tetra/airwave. I've spent half my working life working with telcos, mobile telcos, satellite comms, and backbone providers. I know all about the ins and outs, and won't have really spent anything on this device if tetra ever does get turned off. I'm certainly not planning on producing something commercially.

At the point that emergency services move to LTE it might still be possible to identify/differentiate traffic depending on whether the flagging of their status of emergency services is in the clear or encrypted datastream. If it is added to traffic headers (speedier prioritisation/differentiation by BTS/BSC in major emergencies), then an SDR could still be used to detect but would need something with more grunt than a Raspberry Pi to run it as mass sampling and comparisons would need to be processed.

I only plan on using it on longer motorway runs. I agree that lots of sources will set it off in an urban area, as I stated myself. But, being able to know if I have emergency vehicles getting closer when on the motorway may come in handy... albeit not handy enough for the price of a Target BlueEye

All components will get reused in other projects in future. Programming will take an hour or two. No soldering required, it will all just plug together. So cost is practically nothing.

[BossHogg]

HantsRat said:

yonex said:

I guess, there's a lot of money safety concerns on the roads to take care of?

Yes on a daily basis. I'm guessing you haven't had a family member killed by a speeding or texting motorist before?

Or a colleague!

[Greendubber]

spookly said:

HantsRat said:

What's the point when it will just go off for all masts, hatos, fire engines, ambulances. You'd soon get fed up and turn it off.

Not to mention that tetra is now on it's way out and being replaced soon.

Because you are wrong. Uplink and downlink frequencies are different. It will only scan in the frequency used by the tetra mobile radios, not the network masts. Same as the way Python and Target BlueEye work.

I'm doing it as I already have all the stuff for it, and programming such a simple thing is child's play.

They have been planning turning off Tetra for some time but still haven't, and still have no firm date. 4G networks/LTE are missing some of the key requirements that they have, and surprisingly most mobile telcos don't want the expense of adding them.... and if they did they'd end up with very expensive LTE, just like they had expensive tetra/airwave. I've spent half my working life working with telcos, mobile telcos, satellite comms, and backbone providers. I know all about the ins and outs, and won't have really spent anything on this device if tetra ever does get turned off. I'm certainly not planning on producing something commercially.

At the point that emergency services move to LTE it might still be possible to identify/differentiate traffic depending on whether the flagging of their status of emergency services is in the clear or encrypted datastream. If it is added to traffic headers (speedier prioritisation/differentiation by BTS/BSC in major emergencies), then an SDR could still be used to detect but would need something with more grunt than a Raspberry Pi to run it as mass sampling and comparisons would need to be processed.

I only plan on using it on longer motorway runs. I agree that lots of sources will set it off in an urban area, as I stated myself. But, being able to know if I have emergency vehicles getting closer when on the motorway may come in handy... albeit not handy enough for the price of a Target BlueEye

All components will get reused in other projects in future. Programming will take an hour or two. No soldering required, it will all just plug together. So cost is practically nothing.

So it'll still detect the hand held and vehicle airwave terminals in hato, fire and ambo vehicles?

[Big Performance]

spookly said:

I'm currently building a tetra/airwave detector. Similar to the Python or Target BlueEye.

Built using a Raspberry Pi 3, an SDR and a small LCD screen. Just need to write a python or C++ gui for it and it'll work. I can already scan the relevant frequencies and identify the uplink radio chatter, but until I create an interface I can only see it on a waterfall graph or in raw csv data files.

It isn't breaking the law as the device is incapable of decrypting the traffic, and in this instance is not even capturing encrypted data samples, it simply scans the relevant frequencies several times over 4 seconds then reports back the strongest signal found.

After calibration it should be able to tell you roughly how far the nearest active (ie. switched on) tetra mobile unit is.
I'll set it to display a dB output, but depending on results of calibration I might also create:

• a graph output
• an indicator of whether receive strength is currently rising/falling (ie. likely moving away or towards source)
• number of active channels identified (identify higher/lower number of different sources)
• approximate distance (probably fairly coarse... something like <200m, <500m, <1mile) - this will be indicative only due to lots of factors (reflection, original signal strength, etc)

I already had the RPi 3, and the screen. So total cost is about £25 for a decent shielded SDR. If you wanted to buy all the stuff required on the cheap then you'd be looking at about £60-£70.

I then plan to add a Bluetooth media player, GPS speedo, and possibly add two remote HD cameras to make a dashcam. Will also put it into a case and maybe add battery/ups power.

I expect it to be reasonably useless in urban areas, especially leaving home as I live by a fire stations, and you are never very far from an ambulance, policeman, pcso or fire engine. But it should still show rough distance and whether sources are getting closer or further away.

Edited by spookly on Friday 17th March 10:52

How much to buy one ?

[grumpy52]

Essex area have loads of VW product on the fleet .Golfs,Passats usually in Met Grey or Blue and lots of small VW vans in blue or white .
Kent is mostly skodas with a few fords and the odd Volvo all in Grey or Blue ..
Kent did have a grey Scooby a few years ago .
I have noticed quite a few estates and people carriers being used all over the country .
So in reality anything family sized is suspect .

[frankenstein12]

HantsRat said:

Long gone are the days where lights are drilled into body panels. Most of our unmarked cars now have the blue integrated into light clusters and wing mirrors, near on impossible to spot. Moving away from the dash mounted light too.

You guys are definitely getting harder to spot but not that hard for a ninja like me &#128521;.

I can often spot an unmarked at about 50% of the distance I would spot a full Battenberg. Like in a good game of poker there are tells but not to be unfair to op and others I wont divulge the things that give you away as you will then potentially adapt to conceal the giveaways.

[frankenstein12]

HantsRat said:

yonex said:

I guess, there's a lot of money safety concerns on the roads to take care of?

Yes on a daily basis. I'm guessing you haven't had a family member killed by a speeding or texting motorist before?

Just to be crystal it is not the speed they are grovelling at that causes the accident. The speed merely dictates severity

Teach people to drive properly thereby reducing accidents is THE ONLY way to reduce road deaths.

Handing out speeding tickets will make no difference.

[anonymous-user]

I'm all for unmarked police cars catching proper dangerous drivers especially if it means less 36 in a 30 speed camera pettiness.

[frankenstein12]

Raygun said:

I'm all for unmarked police cars catching proper dangerous drivers especially if it means less 36 in a 30 speed camera pettiness.

I have long thought they should prioritise offences on a scale with speed being lowest priority.

What's needed is education over simple punishment. If someone drives badly and gets pulled they should simply be spoken to and advised on what they should be doing ie have the officers explain what was wrong and how to do it right.

At the same time if double crew the offenders vehicle should be given a Base roadside mot. Vehicle details should be taken as well as drivers and held on a central server for up to 5 years.

If they get pulled for the same offence within 2 years they get a 1 week ban and have to go on an approved advanced driver training programme at their cost.

[anonymous-user]

frankenstein12 said:

Just to be crystal it is not the speed they are grovelling at that causes the accident. The speed merely dictates severity

Teach people to drive properly thereby reducing accidents is THE ONLY way to reduce road deaths.

Handing out speeding tickets will make no difference.

Absolutely. But we have a backwards way of dealing with these things.

[vonhosen]

frankenstein12 said:

Handing out speeding tickets will make no difference.

Of course it makes a difference, it will potentially change behaviour &/or ban from the roads those that don't change behaviour.

My behaviour choices are certainly influenced by the possibility of prosecution. If there was zero potential for it I'd be driving around a lot quicker than I do.

[Derek Smith]

vonhosen said:

Of course it makes a difference, it will potentially change behaviour &/or ban from the roads those that don't change behaviour.

My behaviour choices are certainly influenced by the possibility of prosecution. If there was zero potential for it I'd be driving around a lot quicker than I do.

Research suggests otherwise.

The only significant deterrent is if there is a strong likelihood of getting caught. That has been confirmed many, many times. This is particularly evident in crimes as well.

As you said 'influenced by the possibility of prosecution'. While police patrols are low, the likelihood is very low if you avoid speed cameras.

Another significant trigger for a change in behaviour is if the legislation is supported. I have a friend who ran a business where his salesperson was banned for minor infringements. He went from a supporter of rods policing to a person who knows the behaviour which will be unlikely to gain a ticket.

[vonhosen]

Derek Smith said:

vonhosen said:

Of course it makes a difference, it will potentially change behaviour &/or ban from the roads those that don't change behaviour.

My behaviour choices are certainly influenced by the possibility of prosecution. If there was zero potential for it I'd be driving around a lot quicker than I do.

Research suggests otherwise.

The only significant deterrent is if there is a strong likelihood of getting caught. That has been confirmed many, many times. This is particularly evident in crimes as well.

As you said 'influenced by the possibility of prosecution'. While police patrols are low, the likelihood is very low if you avoid speed cameras.

Another significant trigger for a change in behaviour is if the legislation is supported. I have a friend who ran a business where his salesperson was banned for minor infringements. He went from a supporter of rods policing to a person who knows the behaviour which will be unlikely to gain a ticket.

Of course, as I've said before, it's about both the likelihood of detection & the severity of the punishment.

If you were definitely going to be caught every time, but there was no penalty, then you aren't going to care about getting caught.
If the penalty was really harsh but there was zero chance of getting caught, again you aren't going to care abut the severity of the punishment.

It requires an element of both to have an effect & there is sufficient element of both to influence my & plenty of others behavioural choices.
The sales person didn't change his behaviour & there was obviously sufficient chance of him being detected (he was after all on multiple occasions), so he got banned. I don't want to get banned so my choices will be influenced by that.

[frankenstein12]

vonhosen said:

frankenstein12 said:

Handing out speeding tickets will make no difference.

Of course it makes a difference, it will potentially change behaviour &/or ban from the roads those that don't change behaviour.

My behaviour choices are certainly influenced by the possibility of prosecution. If there was zero potential for it I'd be driving around a lot quicker than I do.

Wrong. Human psych 101.

If a police officer gives someone a ticket for speeding and even a lecture about their speed, when the person drives off the focus of their attention will be on the penalty and its implications. They will in the vast majority of cases feel very aggrieved for receiving a ticket and resentful.

This means that rather than focusing on absorbing any information given by the officer and changing their driving attitude the only lesson learned is that police are there to rip off innocent motorists.

Speed cameras are even worse. There is not even a chance of learning or adapting.

If there was a serious desire to make roads safer speed enforcement would be dropped to the least enforced driving offence. Most of the motorways in my local region are very high speed, free flowing and driving behaviour such as lane discipline is generally better than pretty much any other county I drive through.

It is very unusual to have accidents that either close or restrict traffic flow.

Counter that to for example Essex police. One of the worst police forces in the country jmo. I regularly had to drive up the a12 from London towards Ipswich. I regularly got caught in long traffic jams. Most often near a specific bridge over the A12 where they regularly parked a scam van just after a sweeping bend.

On one occasion there was a rear ender accident caused by someone panic breaking for the speed cam as I went past in the opposite direction on another occasion passing the same way the road was closed with police ambulance and fire crews and two very badly damaged cars one of which had clearly been hit from behind and spun into the central reservation nose first.

Interestingly there was a layby with a caf and one day heading home I pulled in for some lunch and the cam van was in its usual spot. While I sat outside eating my lunch watching traffic go by there were a number of very near misses from people panic braking.

The camera was blatantly causing lots of accidents yet they kept putting it on the bridge.

[Greendubber]

Are drivers totally void of any responsibility then?

[spookly]

Greendubber said:

So it'll still detect the hand held and vehicle airwave terminals in hato, fire and ambo vehicles?

Yep.
But better to be aware something is there, than not be aware at all.