Interesting device that detects the present of police(and emergency) radios.... - Page 1
Forum section: electronics / projects

author: george graves
author_rank: Super Contributor
timestamp: October 27, 2014, 09:07:57 am
content: Saw this pop up on some of my feeds...."Police Infuriated About New “Cop Detecting” Device That Warns People When a Cop is Near"http://thefreethoughtproject.com/police-infuriated-cop-detecting-device-senses-equiptment/#cH3W4l1XVBk5kdMR.99Price seems to be well above $1000. ($1600 - or so)Two things are worth talking about.A.) Is it, or should it be legal? (I say, if you're broadcasting radio waves into my brain, I'm free and clear to pick them up and measure the signal strength)B.) the $1600 price tag is a bit steep - but I get it's a nitch item. I wonder if a RasberryPi and SDR could do the same thing?On to point B. How would one detect only the mobile transitions, and not the base stations or repeaters?

author: tggzzz
author_rank: Super Contributor
timestamp: October 27, 2014, 09:36:35 am
content: Regardless of legality, is it wise to "annoy the police" without a very good reason? If so, what might be a sufficiently good reason?There are far more ways the police can annoy and inconvenience you.

author: tinytim
author_rank: Contributor
timestamp: October 27, 2014, 11:48:53 am
content: Illegal for use in the UKLegal for use in USAI wonder if the "front end" can be retuned to accommodate different frequency bands...Will have to google this, looks pretty good but depends on transmission from a known frequency pair in order to alert you, ambulance service can be detected already by using the MDT tx freq, not that i ever decode those signals because that would be illegal for me...

author: Bored@Work
author_rank: Super Contributor
timestamp: October 27, 2014, 04:59:08 pm
content: Quote from: tggzzz on October 27, 2014, 09:36:35 amOr as they sing in a famous rock and roll songI fought the law and the law won.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 27, 2014, 11:05:43 pm
content: Quote from: tinytim on October 27, 2014, 11:48:53 amOn what basis ? You're detecting presence, not eavesdropping.

author: tonyarkles
author_rank: Regular Contributor
timestamp: October 27, 2014, 11:31:36 pm
content: Kind of makes me want to take an RF Explorer and build new firmware for it. You can get it off seeedstudio for $179 (http://www.seeedstudio.com/depot/RF-Explorer-ISM-Combo-p-1092.html?cPath=63_64)and the schematics are all available (https://code.google.com/p/rfexplorer/wiki/RF_Explorer_schematics).

author: tggzzz
author_rank: Super Contributor
timestamp: October 28, 2014, 12:09:30 am
content: Quote from: mikeselectricstuff on October 27, 2014, 11:05:43 pmAh. The "metadata doesn't count as interception" argument. I'd love to see how that played out in courtBut they would 't use that to convict; I'm sure theres a relevant clause in the Wireless Telegraphy Act.

author: CBP
author_rank: Contributor
timestamp: October 28, 2014, 12:28:31 am
content: For the UK I am not sure how valuable it would be, look at the Airwave sharers list for how many different agencies use Airwave (which I guess the UK version has been set up to use), it is not just the emergency services and it would have no way of differentiating between a police officers terminal and that belonging to an immigration officer, the council or some other agency.Certainly for England & Wales I don't think the WT Act covers it but depending on the situation a device was found (thinking wildly here) in you might be able to stretch a going equipped charge out of one of these things.

author: bigsky
author_rank: Regular Contributor
timestamp: October 28, 2014, 12:48:19 am
content: See this link for some UK case law that considers a similar subject:http://www.pepipoo.com/Roadside_radar.htm

author: george graves
author_rank: Super Contributor
timestamp: October 28, 2014, 09:42:56 am
content: Well UK law aside....what would it take to monitor a frequency, and then show it's strength? Seems so easy - what hasn't it been done before? What am I missing?

author: jc101
author_rank: Frequent Contributor
timestamp: October 28, 2014, 09:52:12 am
content: In the UK there are over 300 sharer organisation for Airwave, so knowing a terminal is around isn't going to be that big a deal. That said, the tenders are out for a replacement system, which is expected to be based around the current existing telecommunications solutions (i.e. based around the mobile networks) using various priority services on that. It may even help get better coverage for the rest of us!The current Tetra based solution is likely to be replaced by 2020, having been involved in the rollout of the original it will be interesting to see how the transition is managed.One side note, the day it went live in my county the press office was overloaded with calls. All the people who used to listen in with scanners lost all their info, so the press and media had to phone in to find out about incidents.

author: ConKbot
author_rank: Super Contributor
timestamp: October 28, 2014, 04:20:04 pm
content: preamp, filter, RF detector. ILLEGAL

author: tinytim
author_rank: Contributor
timestamp: October 28, 2014, 09:07:13 pm
content: After having a hunt round on the amended WTA 1949 it does in fact seem that i was incorrect so thanks to everyone for pointing that out. seems like the law got updated but i neglected to double check my facts.... my bad.

author: AG6QR
author_rank: Frequent Contributor
timestamp: October 28, 2014, 10:59:26 pm
content: That's news? I've had 154.905MHz programmed into my 2 meter ham radio for a long time. That's the frequency used by the California Highway Patrol (CHP) to relay their dispatch channel to the officer's handheld radio. A relay radio in the patrol car receives the dispatch channel from the main tower, and retransmits it on 154.905 to the handheld units. Similarly, the handheld units transmit to the patrol car, and it uses its more powerful transmitter to relay the transmission back to the dispatcher.In some areas, the CHP is switching over to digital systems for performing this function. But it still works where I am, in plain old unencrypted unencoded FM. I can often hear dispatch traffic, and when I do, the signal strength gives me a good idea of how close the patrol car is. There has been more than one time when it has alerted me to a potentially dangerous situation in front of me, or a crazy speeding driver behind me headed my way.In the US, in many states, it's legal for anyone to monitor police communications, even while driving. But not in all states. However, even in those states which generally outlaw mobile scanner use, they've got an exception for licensed ham radio operators using the receivers built into their ham radio units.But the frequencies to use vary widely from place to place over here.

author: tinytim
author_rank: Contributor
timestamp: October 28, 2014, 11:05:46 pm
content: we do not have the luxury of being able to monitor police transmissions legally in the UK.The police used to operate around 152-158Mhz(ish) and yes, what they dont know doesnt hurt.At least your gov allows you to monitor73.

author: Melt-O-Tronic
author_rank: Frequent Contributor
timestamp: October 30, 2014, 07:51:28 am
content: I don't see that being practical in the US. Police frequencies are scattered around multiple bands, intermingled with other services and they use a variety of modes. In many areas, police, fire and EMS share frequenciesFor example, in my area, the county Sheriff's office has one frequency around 155 MHz and it's P25 digital. All city police, fire and EMS share another frequency and that's FM narrowband. There is commercial traffic on nearby frequencies.For that to work here (and not be crippled by false positives), it would need GPS and a continuously updated database of frequencies & modes that are geographically categorized. RadioReference.com's database would be a good start, but not the full solution.

author: TheNewLab
author_rank: Frequent Contributor
timestamp: November 20, 2014, 07:49:26 am
content: This thread may be dead already, only I have to laugh!What a name!Interesting device that detects the present of policeDoes it work when I am walking on foot? How about at Banks?I really love the title!Can a women with a cop fetish use it to pick up cops? How about a guy who is into dating female cops?I love it!

author: george graves
author_rank: Super Contributor
timestamp: November 23, 2014, 01:01:13 pm
content: Quote from: TheNewLab on November 20, 2014, 07:49:26 amLOLOLololololol. Well thanks for the bump to a old thread. Your interest in fetishes is kinda odd. But - hey - what ever floats your boat - no judgment here. This sex forum seems to have a electronics problem!No - no one really answered the more basic question. A small computer (Say raspberry pi) and a SDR dongle. And knowing your local frequencies, of police and what not, why doesn't someone build a meter that would show you that? AG6QR more or less answered it(thanks!). I just thought it was an interesting idea, and the product is being sold for $$ - so hence the post. That's all. No gimp mask was needed.Quote from: AG6QR on October 28, 2014, 10:59:26 pm

author: GEuser
author_rank: Frequent Contributor
timestamp: November 23, 2014, 03:56:06 pm
content: It's Alive stillLook up "Close Capture" by Uniden , its been out for yonks ... no good for digital though ..edited/added and true , from what I've heard on those channels it's no wonder they want the audio digitized imo of course ..

author: KG7AMV
author_rank: Frequent Contributor
timestamp: November 23, 2014, 09:18:13 pm
content: I have a BCT-15 Police Scanner Installed In My Hummer H2... Replaced the On-(Spy)star with it! Cool device if it actually works!

author: SL4P
author_rank: Super Contributor
timestamp: November 25, 2014, 04:49:15 am
content: Quote from: KG7AMV on November 23, 2014, 09:18:13 pmWhat are those things? BCT-15? Hummer H2?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 25, 2014, 05:20:56 am
content: I got a present from the police once. It was a jaywalking ticket. I didn't like it.

author: G7PSK
author_rank: Super Contributor
timestamp: November 26, 2014, 09:12:40 am
content: Quote from: tinytim on October 27, 2014, 11:48:53 amNot sure it is illegal in the UK. It would be illegal if you decoded the information but just detecting the presence of an RF signal is not.

author: EEVblog
author_rank: Unknown
timestamp: November 26, 2014, 09:55:03 am
content: Quote from: george graves on October 27, 2014, 09:07:57 amYep, that.

author: GEuser
author_rank: Frequent Contributor
timestamp: November 26, 2014, 10:22:40 am
content: A H2 looks funny , unless the picture has been reversed left to right or is that right to leftwhatever it is those gauges should be on the Right side not the Wrong side excuse the deliberate pun ...

author: ConKbot
author_rank: Super Contributor
timestamp: November 26, 2014, 12:01:49 pm
content: Quote from: GEuser on November 26, 2014, 10:22:40 amOn the right side you say? This may look more familiar to you then(cmon making it too easy! )

author: GEuser
author_rank: Frequent Contributor
timestamp: November 27, 2014, 10:57:44 am
content: I got dizzy looking at that !@ kg7amc , one has probably found out by now with the new bct15 , the minimal signal it will lock onto is the strongest that gets over (if any) that are already there , explanation> say one has a 10 over 9 data signal that is there 24/7 even if locked out for rx manually means the unit will only lock onto a 10 over 9 or more signal that is either closer and/or just stronger but is has to be stronger than the original 24/7 10 over 9 one .I have a farm water pumpssystem 20w 10km away nearly full scale 24/7 , they talk to each other but in bursts so as long as a S3 signal turns up between those bursts it'll lock on , a reliable lock on every time is a mobile or base at around 5km as they usually be 25w or more jfi .