Cheap Car Speed Trap Radar Detector Teardown

[jonovid]

product claims to give an audible notification of speed trap radar
if detecting or reception of frequency of 22.8 - 24.5 GHz K-band , X-band: 10.525GHz , VG-2: 11.150GHZ

as the two pcb's are only linked by three wires . positive & negative supply , with one pin for data.
this gives opportunity for experimentation. using the microwave detector pcb independently from the rest of the system.  see the 3 wire link.
between the two pcb's.
radio amateurs maybe interested as its a dirt cheap microwave detector.
the other pcb is a talking audible notification with speaker and the LED segment display.
the mini c USB part is for an add on laser detector accessorie sold separately.
this cheap radar detector also comes with a 12 volt lighter adapter.
instructions in Russian.


I got my unit for passive air traffic radar experimentation maybe using a cooking wok as a microwave dish to increase the antenna gain.
so far I have only posted the teardown images of it here. as others have better microwave reception skills then I do have more opportunity to repurpose.

[Halcyon]

Probably a good time to remind anyone in Australia that possession of these devices is illegal. Don't get caught with one of these in your car! (I believe WA is the exception here.) Last I issued one of these tickets out, it was around $2000 plus 9 demerit points (that was years ago now).

That being said, I've seen these devices work pretty effectively for the type of radar used in police vehicles in Australia. In NSW, police vehicles are fitted with the Kustom Eagle II or III radar systems which produce a strong but relatively narrow beam around 33 to 36 GHz. However unlike on television or in video games, police don't just drive around with the radar beam "released" constantly. When it's not being used to actively measure the speed of a vehicle, the beam is off and thus can't be detected. Additionally, measured speed (e.g.: Radar/LIDAR) are only used to confirm a police officer's own observations, so if a police officer points a radar or LIDAR device at your vehicle, it's probably already too late.

Speaking of LIDAR, in my experience, these detectors are almost always completely useless at detecting them. Not only because, like radar, they beam is instantaneous, but they too use a narrow beam and it's largely going to depend on where the device is being aimed. As cars become more automated, I suspect the number of false positives (by units which are advertised to detect LIDAR) will increase.

With respect to fixed speed cameras (again, speaking from my experience in NSW, but also applies to other parts of the country), these detectors are ineffective as fixed speed/red light cameras don't use radar or LIDAR, but rather induction loops installed in the road surface.

Some states also have "mobile" speed cameras that are usually operated by the state's roads authority (through a contractor like Acusensus). These units are fitted to regular vehicles and typically use a "slant" radar, which allow for detection across multiple lanes (or even in both directions on a road), but at the expense of detection range. These slant radars output a pretty weak signal and by the time your detector might pick up on it, the camera car has probably already obtained a reading of your speed. You almost need to be on top of it for some of these radar detectors to work. Your best defence is to use your own eyes and be observant.

I know I'll get comments both for and against these laws, or even people being critical of me stating that "I should know better". I'm not going to engage in a political debate. I'll simply say that whilst I absolutely don't condone breaking the law, let's not kid ourselves, most of us exceed the speed limit in a way that's still safe, even if it's technically breaching the road rules. If you are going to speed, drive to the road conditions (and those around you), don't exceed your own skill level or the capabilities of your car, and if you do get caught, take responsibility for your own actions rather than trying to lie your way out of it (the "attitude test" is real).

EDIT: Possession of Radar/LIDAR detectors in vehicles are unlawful in all Australian states and territories (including Western Australia, where they were legal prior to October 2020).

[Stray Electron]

     I don't think that the police have used RADAR in the US for over 30 years.  I bought a used ex-police RADAR gun at a garage sale about 20 years ago for $5.  I don't even know what happened to the radar detector(s) that I never owned.

   Radar detection devices aren't actually illegal in the US but some states like Virginia would give you a very hefty fine if they caught you with one. Like $250 in 1975 dollars.  There is a law on the books in many states that was written in the 1930s that made it illegal to own equipment that could be used to listen in to police radio broadcasts. Virginia and a few other states made a very liberal interpretation of that law to charge people that possessed police radar detectors, even if they weren't using it. Even though by the 1970s, people could and frequently DID listen into police radio broadcast with impunity and police radio scanners could be bought in any Radio Shack.

  The police in the US now use LiDAR and there are LiDAR detectors but LiDAR operates so fast that by the time that you get the warning, The LiDAR has already recorded your speed.  LiDAR is also more directional than RADAR so unlike RADAR you can't detect it unless it's pointed directly at you. 

[tautech]

Unlike here in NZ where RADAR detectors are legal.

These cheap ones are so cheap it's nuts if you don't stock up on them:
https://www.emax.co.nz/360-Degree-V7-Radar-Detector-8526.html

However their performance doesn't compare with my 20yr old Escort X50 swiped from the son when he moved to WA where it certainly is illegal to have them.

[Halcyon]

However their performance doesn't compare with my 20yr old Escort X50 swiped from the son when he moved to WA where it certainly is illegal to have them.

I stand corrected. That law was changed in 2020 to bring WA in-line with the rest of the country.

[CatalinaWOW]

Sounds like the laws in Australia are much like those in many US states, which DON'T outlaw possession of these things, but do outlaw operating them (and possibly possessing them) in a moving vehicle.

This would leave owning one for experimentation as proposed by the OP perfectly legal.  But as always, I am not a lawyer and so get real data from a good lawyer who specializes in the appropriate fields of law if it really matters to you.

In my limited on the road experience with these things my experience is much like Halcyons.  Little if any better than just paying attention and slowing down at obvious locations for speed traps.  And many false alarms from microwave sensors in automatic door openers.  His advice is also sound.  Drive safely and take responsibility for how you drive.     

I am not a microwave expert but this looks about as I would expect inside.  Perhaps the most interesting thing to me is that although the instructions are in Russian, there is not a single Cyrillic character to be seen inside.  Not on the castings.  Not on the PWB and not on the components.

[tautech]

Drive safely and take responsibility for how you drive.     

This.

Here in NZ the agenda is protect us from ourselves and bombard us with speed signs are not a target speed however after 4 weeks in WA over Xmas, their speed signs definitely are the target speed !
Very refreshing it was too to see how WA just got on with what they had to do.
Everyone travelled at the limit but never over except for a very few.

Here many use the speedsters as RADAR bait and foolishly many go outta their way to keep up with them, putting themselves at risk driving beyond their competency. 

[Halcyon]

Drive safely and take responsibility for how you drive.     

This.

Here in NZ the agenda is protect us from ourselves and bombard us with speed signs are not a target speed however after 4 weeks in WA over Xmas, their speed signs definitely are the target speed !
Very refreshing it was too to see how WA just got on with what they had to do.
Everyone travelled at the limit but never over except for a very few.

Here many use the speedsters as RADAR bait and foolishly many go outta their way to keep up with them, putting themselves at risk driving beyond their competency. 

As with most things, laws are targeted at the lowest common denominator (or it's an economic decision). It's quicker and cheaper to reduce a speed limit after a series of fatal crashes, rather than looking into the root cause of the crash and perhaps re-engineer the road or some other solution. Regardless of the rules, there will always be people who will try to find some way "around the system". That's human nature. How many decades have we known about the dangers of drink driving, or mobile phone use, yet some people will just keep doing it.

Personally, I hate the use of cameras for offences where the situation is not black and white (e.g.: Speeding). I never bothered with anyone simply exceeding the limit by 10 km/hr (unless it was a school zone). I would rather see every intersection have a red light only camera, and re-invest the money in more police on the road to educate motorists and enforce road safety. Police have discretion, cameras do not. Police can detect and deal with multiple offences simultaneously, cameras are generally limited to one or two. Drivers who continually fail to get the message can catch the train/bus.

[vk4ffab]

Drive safely and take responsibility for how you drive.     

This.

Here in NZ the agenda is protect us from ourselves and bombard us with speed signs are not a target speed however after 4 weeks in WA over Xmas, their speed signs definitely are the target speed !
Very refreshing it was too to see how WA just got on with what they had to do.
Everyone travelled at the limit but never over except for a very few.

Here many use the speedsters as RADAR bait and foolishly many go outta their way to keep up with them, putting themselves at risk driving beyond their competency. 

As with most things, laws are targeted at the lowest common denominator (or it's an economic decision). It's quicker and cheaper to reduce a speed limit after a series of fatal crashes, rather than looking into the root cause of the crash and perhaps re-engineer the road or some other solution. Regardless of the rules, there will always be people who will try to find some way "around the system". That's human nature. How many decades have we known about the dangers of drink driving, or mobile phone use, yet some people will just keep doing it.

Personally, I hate the use of cameras for offences where the situation is not black and white (e.g.: Speeding). I never bothered with anyone simply exceeding the limit by 10 km/hr (unless it was a school zone). I would rather see every intersection have a red light only camera, and re-invest the money in more police on the road to educate motorists and enforce road safety. Police have discretion, cameras do not. Police can detect and deal with multiple offences simultaneously, cameras are generally limited to one or two. Drivers who continually fail to get the message can catch the train/bus.

I do not have a problem with speed cameras, police trickery by putting cameras at the bottom of hills or any other mechanism used to catch people out, the simple solution to all this is do not speed. I have not had a ticket in over 20 years by not playing Dick Johnson and Peter Brock on the roads.

[p.larner]

here in the uk they are not for making the roads safer but a cunning way to collect money,guess its the same in most places nowadays?.

[Andy Chee]

Certainly the automated speed cameras are seen by many as revenue raisers, due to their typically low margin (e.g. 3kph over the posted limit)

OTOH, if a patrol officer detected you on their handheld speed gun, usually they wouldn't waste their time chasing after you if you were only 3kph over.  Usually they chase after bigger targets like 15kph and over, in which case, you deserve to be pulled over.

[Halcyon]

Certainly the automated speed cameras are seen by many as revenue raisers, due to their typically low margin (e.g. 3kph over the posted limit)

OTOH, if a patrol officer detected you on their handheld speed gun, usually they wouldn't waste their time chasing after you if you were only 3kph over.  Usually they chase after bigger targets like 15kph and over, in which case, you deserve to be pulled over.

That and there is an automatic 3 km/hr error applied to speed measurements by policy. Different devices have varying amounts of error by nature of how they are designed, distance of travel, whether the measuring device is stationary or moving, and cosine error all have some impact on measured speed. Likewise, doing silly things like shooting LIDAR through the front window of a vehicle is a no-no. The error (at least in Australia) always favours the motorist.

There are plenty of rumours going around about how much leeway there is in radar measurements. 10% is often cited, which isn't entirely correct, but near enough for the purposes of the general public.

[SeanB]

Here by me in S. Africa nobody has RADAR detectors any more, as no police uses them. You get the temporary cameras with LIDAR, where detecting the beam comes with you already having seen the flash, telling you to expect a nice holiday picture, or with you getting a hint to pull over by the cop at the side of the road. There $50 and the fine vanishes, cost of traveling on the road. 

Small towns you will see, Monday to Sunday, 305m in from the sign that says "Y district limit", with the 60kph sign, a camera with 2 lines on the road, and depending on the town either genuine film camera, old models still in calibration, and with a high fine to cover the film cost, or more modern ones digital camera, still with the high fines, but set to 67kph as trigger point, not 81kph with the film. Those towns use the camera revenue to fill the town coffers, with locals getting a big discount on the fines, because they will go pay them within 14 days, before the notice reaches them via post. The rest get sent via post, which might take 6 months to be delivered, so they either pay online and avoid the by now passed court date, or come fight it by the magistrate, and run the risk of getting a contempt of court fine tacked on as well. Often the only way you know you have one is you go renew vehicle registration, and get a form with the disk area blank, and a note saying your penalty is x, and you have to settle it first, then apply again.

But by me, in a major city, no police speed enforcement for the last decade plus, due to incompetent police force not paying for the certification, and then having to pay back an entire year of fines forced on them by the court. Then found out that they cannot use the single supplier certified, due to non payment, and them having supply chain rules that prevent them from paying for it. Multi millions of dollars in revenue gone, because some council members cannot make a decision and admit they were wrong. Note 3 mayors as well, 2 found guilty of corruption, and moved elsewhere, and the current one not found guilty yet.

[jonovid]

two more images missing from the list
the label on the bottom of the case & the instructions that came with the unit.
80% is in Russian.  20% English or Chinglish

[szoftveres]

A bit of analysis by the photo:

The RF input is coming through a structure 1) that seems to be something similar to choke flange feed, 2) is the first broadband LNA with its input capacitively coupled to the feed. 3) is an LC lowpass filter, presumably to filter out everything above the maximum frequency. 5) and 6) form a diplexer; according to the OP this device detects radar signals between 22.8 - 24.5 GHz (RF path through the capacitor marked 6) and 10.525 - 11.150GHz (RF path through the dual LC lowpass filter marked 5). 4) is an open narrowband stub, presumably to act as a trap for some in-between bands. 7) is the 2nd LNA for the higher frequency band with its 8\) biasing network and 9) attenuator pad on its output.

The 4-pin device 12) bias-filtered by 10) and 11) could be the oscillator-mixer for the higher band, with the SOT-23 MMBT3904 15) actively biasing it via 14). In that case the L-shaped line 13) is the main λ/2 resonator, with the LC 14) filtered Vdd (or Vcc) arriving to its center (zero impedance) point from the MMBT3904. Feedback to the gate (or base) of the oscillator is capacitive, implemented by the diagonal line. IF (or baseband) output is via 11) LC lowpass filter.

[radiolistener]

Probably a good time to remind anyone in Australia that possession of these devices is illegal.

As I understand this is just a receiver, it don't transmit anything. It cannot be illegal, because it don't affect anything.
Prohibiting such things is equivalent to prohibiting having a television or radio.

Nice RF PCB layout.

[Halcyon]

Probably a good time to remind anyone in Australia that possession of these devices is illegal.

As I understand this is just a receiver, it don't transmit anything. It cannot be illegal, because it don't affect anything.
Prohibiting such things is equivalent to prohibiting having a television or radio.

That's not the way law (or the world) works. It's like saying a firearm is just a metal tube.

[CatalinaWOW]

As with most things, laws are targeted at the lowest common denominator (or it's an economic decision). It's quicker and cheaper to reduce a speed limit after a series of fatal crashes, rather than looking into the root cause of the crash and perhaps re-engineer the road or some other solution.

I have some sympathy for that scenario.  But in two cases that affected roads I drive regularly teenage drivers exceeded posted limits by multiples (2X in one case, more than 3X in the other based on post crash forensics) and killed themselves and their passengers.  Parents of those involved assuaged their emotions by demanding a lower speed limit, and politicians took the path of least resistance and did so.

Call me naive, but I don't believe a lower speed limit would have changed a thing for these drivers, nor for any future similar idiots who are driving far beyond their capability.  It is just a case of virtue signaling, with no measurable affect on safety.

[Halcyon]

As with most things, laws are targeted at the lowest common denominator (or it's an economic decision). It's quicker and cheaper to reduce a speed limit after a series of fatal crashes, rather than looking into the root cause of the crash and perhaps re-engineer the road or some other solution.

I have some sympathy for that scenario.  But in two cases that affected roads I drive regularly teenage drivers exceeded posted limits by multiples (2X in one case, more than 3X in the other based on post crash forensics) and killed themselves and their passengers.  Parents of those involved assuaged their emotions by demanding a lower speed limit, and politicians took the path of least resistance and did so.

Call me naive, but I don't believe a lower speed limit would have changed a thing for these drivers, nor for any future similar idiots who are driving far beyond their capability.  It is just a case of virtue signaling, with no measurable affect on safety.

Correct, in those extreme cases, the speed limit itself is entirely pointless and arbitrary. It's impossible to legislate against stupidity and unfortunately, some people will die as a consequence of their actions.

[BradC]

However their performance doesn't compare with my 20yr old Escort X50 swiped from the son when he moved to WA where it certainly is illegal to have them.

I stand corrected. That law was changed in 2020 to bring WA in-line with the rest of the country.

Thanks for the correction. It appears I've been lucky in not being caught and I've now taken the bird dog out of the car. Didn't know the law had changed.

[BradC]

As I understand this is just a receiver, it don't transmit anything. It cannot be illegal, because it don't affect anything.

Oddly enough that's not the case. Radar Detector Detectors work by picking up the local oscillator from a radar detector which tends to leak from the horn. So while in theory they're not transmitters, in practice they tend to be. I have a specially filtered and attenuated Bell radar detector, but the right RDD will still pick it up,

[radiolistener]

That's not the way law (or the world) works. It's like saying a firearm is just a metal tube.

No, using firearm can do harm and damage for other. This is why it requires license.
Using receiver cannot do harm and damage for others, because it don't have emission.
But radio transmitter can do, this is why using radio transmitter requires license and using radio receiver don't needs license.

The same thing with these radar detectors, its just detect radar nothing else, it does not interfere the correct operation of the radar.

But if you use active anti-radar, which uses transmitter in order to jam and interfere the correct operation of the radar, it will require license to use it.

picking up the local oscillator from a radar detector which tends to leak from the horn

local oscillator power is much below power limit for the devices which require license.
The limit is about 10-50 mW depends on frequency and local law specific.

It is safe to use local oscillator and receivers with no license.

And after all, you can build radio receiver which don't have local oscillator working on radar frequencies. This is not a problem to do frequency shift and receive it on different frequency. So you will be unable to detect radar detector because it will not use any radar frequency at all. 


PS: for receivers there are possible some nuances, because some receivers architecture can produce pretty strong emission and even can interfere nearby receivers, but usually all receivers RF power leakage is much below power limit for unlicensed usage.

[Halcyon]

That's not the way law (or the world) works. It's like saying a firearm is just a metal tube.

No, using firearm can do harm and damage for other. This is why it requires license.
Using receiver cannot do harm and damage for others, because it don't have emission.

You're looking at this with an over-simplistic view of the world.

Imagine someone who is exceeding the speed limit, who might have ordinarily have been caught doing the wrong thing and learnt a lesson, but didn't because they had a radar detector. Maybe it worked just that one time, maybe it got them off-the-hook several times. What if that person then goes on to drive like an idiot, over-estimating their driving ability or thinking "they won't get caught" and takes additional risks? THAT could have direct results.

Another way you could look at it is the "Swiss Cheese Model". A disaster might not occur because "only" x-number of factors align, but all it takes is y-number of factors to align and someone ends up dead, severely injured or even on the low-end of the spectrum, having to pay for costs they wouldn't ordinarily have incurred.

On one occasion, I personally attended a fatal collision between a car and a power pole because the driver simply slowed down for the speed camera, only to speed back up again thinking he "got away with it". That driver slammed into a pole due to his own cockiness several hundred metres down the road from the camera and killed his rear passenger who wasn't wearing a seatbelt. I had to knock on that family's door late at night and tell them that their daughter/sister had been killed.

Laws are mostly there for a good reason. A radar detector is simply an instrument designed to evade those laws. There might be a positive outcome for the individual, but there is only negative outcomes for the rest of society. I cannot think of a valid reason why anyone would drive around with a radar detector inside their car, apart from selfishness.

[radiolistener]

You're looking at this with an over-simplistic view of the world.

No, on the contrary, I just well understand many possible issues of other approaches.
As you probably know, the best solution for some issue is always looks simple, but at the same time has deep and complicated reasons.

What if that person then goes on to drive like an idiot

You cannot punish people just for your assumptions.

The law cannot be based on lie, assumptions or fabrications.
You're needs to use strongly documented and verifiable facts in order to bring a person to justice.

For example if some human has hands, you cannot punish him just because you're thinking that he can use hands to make some bad things. If you want to punish someone, you're need to have a strongly documented proof what exactly bad things he already did.

Using lie, assumptions or fabrications to punish someone is illegal.

[radiolistener]

On one occasion, I personally attended a fatal collision between a car and a power pole because the driver simply slowed down for the speed camera, only to speed back up again thinking he "got away with it". That driver slammed into a pole due to his own cockiness several hundred metres down the road from the camera and killed his rear passenger who wasn't wearing a seatbelt. I had to knock on that family's door late at night and tell them that their daughter/sister had been killed.

Are you sure that without radar detector it will be possible to get less death?
If that driver didn't simply slowed down, it may lead to much worse catastrophe, with much more death...
Just because higher speed leads to higher damage with non linear dependency. Isn't it?

May be radar detector is the only thing which allowed to minimize number of victims in this incident. And it saves a lot of lives... Who knows?

Did you hear about Butterfly Effect?

I cannot think of a valid reason why anyone would drive around with a radar detector inside their car, apart from selfishness.

You cannot judge and punish persons just because you thought that he can do some harm for others. You can analyze things and make fabrications for yourself, that is your right. But you cannot use your own fabrications in order to blame or punish someone if you don't have valid and verifiable facts that exactly that people already did bad thing. Just because fabrications can be used to blame anyone for things which he never did and even didn't wanted to do. Such behavior is not justice, but speculation and fraud.

The passive radar detector cannot make harm for others. It don't affect radar function. That is the fact.
All other things like "if people know about radar he can do bad things" is just a speculation.

In practice, when humans know that their actions are monitored they tend to commit fewer violations.
It means that these who have radar detector tends to do less violations, because they see signs that their speed is monitored.