Detection of Scanner Use

[kikito]

Build a little osc that sends out the PD freq + 10.7.

LOL, then let them look for the scanner!

Now that is the fun way to go!

 

[rinkerk]

Re: Detection of scanner use.

Yeah,
I'd have to agree with Kb2xxa.
That pic would attract attention im my area.
I have read alot of posts from people who try to conceal their antennas in an effort to be "stealth"
I dont know the exact state laws regarding mobile use of any receiver ( or for that any tranceiver). My experience here in NM is talk with the local county sherrifs in the area. I just found out they will be switching to a 800 EDACS system within the next year or so.
Paranoia will Destroya

 

[Voyager]

There's so many gadgets out there today that people use (AM/FM radio, etc.) that might use oscillators or create enough interference to block picking up such, that to specifically pick up a local oscillator from a specific scanner is not only hard but a waste of time for anybody to do.

LOL, you cald actually have some fun if they were doing that.

Build a little osc that sends out the PD freq + 10.7.

LOL, then let them look for the scanner!

Most scanners I've tested are low injection on VHF, so you would want it PD - 10.7 MHz, although the injection could be on either side.

You would have to be really careful about building such an oscillator. They find this little black box in your car that generates an RF carrier. Do YOU want to try to explain to them that it has nothing to do with a detonator? They may be having the last laugh when they tear your car apart looking for other questionable devices. Then you have to explain to the judge that it was just a joke and you were trying to trick them into thinking there was a scanner in your car because you knew it was not legal. I don't think you would be the one laughing.

Joe M.

 

[N_Jay]

There's so many gadgets out there today that people use (AM/FM radio, etc.) that might use oscillators or create enough interference to block picking up such, that to specifically pick up a local oscillator from a specific scanner is not only hard but a waste of time for anybody to do.

LOL, you cald actually have some fun if they were doing that.

Build a little osc that sends out the PD freq + 10.7.

LOL, then let them look for the scanner!

Most scanners I've tested are low injection on VHF, so you would want it PD - 10.7 MHz, although the injection could be on either side.

You would have to be really careful about building such an oscillator. They find this little black box in your car that generates an RF carrier. Do YOU want to try to explain to them that it has nothing to do with a detonator? They may be having the last laugh when they tear your car apart looking for other questionable devices. Then you have to explain to the judge that it was just a joke and you were trying to trick them into thinking there was a scanner in your car because you knew it was not legal. I don't think you would be the one laughing.

Joe M.

You are just a bit paranoid.

LOL, lets see less than 100 mw, part 15, that one would be one hell of a probable cause case for searching your vehicle.

 

[Heterodyne]

Come on, man.. This whole thread is being fueled by a big red jerry can with the word "PARANOIA (tm) BRAND GASOLINE" written on the side.

 

[djeplett]

If I understand all this correctly then it's along the lines of the radar detector detectors, correct? The way I understood it, some states with radar detector laws used to (or still do) have radar detector detectors in some of the police units so the officers can tell if someone has a radar detector in their car. At least that's what a dispatcher friend I knew about 10 years ago told me.

I thought it was a load of BS but then I saw detectors that came on the market that had "stealth" circuitry that somehow circumvented this. In order to stop this, any reciever wishing to be "stealth" would have to be heavily shielded to stop these emissions from the IF circuit, correct?

I also think I've had my old radar detector give false alerts when another car is passing. I'd guess it was because it was detecting the other car's unit, right?

 

[Voyager]

There's so many gadgets out there today that people use (AM/FM radio, etc.) that might use oscillators or create enough interference to block picking up such, that to specifically pick up a local oscillator from a specific scanner is not only hard but a waste of time for anybody to do.

LOL, you cald actually have some fun if they were doing that.

Build a little osc that sends out the PD freq + 10.7.

LOL, then let them look for the scanner!

Most scanners I've tested are low injection on VHF, so you would want it PD - 10.7 MHz, although the injection could be on either side.

You would have to be really careful about building such an oscillator. They find this little black box in your car that generates an RF carrier. Do YOU want to try to explain to them that it has nothing to do with a detonator? They may be having the last laugh when they tear your car apart looking for other questionable devices. Then you have to explain to the judge that it was just a joke and you were trying to trick them into thinking there was a scanner in your car because you knew it was not legal. I don't think you would be the one laughing.

Joe M.

You are just a bit paranoid.

LOL, lets see less than 100 mw, part 15, that one would be one hell of a probable cause case for searching your vehicle.

Not paranoid - just very cautions of sticking the proverbial crooked stick in the hornet's nest. Do you really think most cops know about Part 15? After 9/11, do you really think they are going to say "well, it's just a Part 15 device, so you can be on your way."? You don't think their finding a mysterious home built transmitter is PC for searching the vehicle?

Think about it this way: You are building a device that emits the same frequency as a receiver's LO (with the same IF) on a police frequency. Granted, the range is limited, but let's use the argument that your intent may be to interfere with the reception of transmissions on a particular receiver. Is that reasonable to think that's possible motive? (whether or not it would actually be strong enough to work)

It's like the guy who carrys a plastic gun through the security checkpoints at the airport just to prove it can be done. There is technically nothing illegal about it (AFAIK) as long as it's not real, but you don't think they are going to be put through the 'whole enchelada'? Maybe his intent was to make people THINK it was a gun to hijack a plane.

Another case: The kid who dressed up for Halloween as a fireman for school (everyone dressed up). He had a plastic axe (it came as part of the costume). He was suspended for bringing a weapon onto school grounds. Did he do anything wrong?

There is a lot of stupidity out there anymore. It's good to avoid antagonizing those who can make your day 'less than pleasant'.

Again, it's not paranoia - it's sensible caution for a post-9/11 USA.

Joe M.

 

[Voyager]

If I understand all this correctly then it's along the lines of the radar detector detectors, correct? The way I understood it, some states with radar detector laws used to (or still do) have radar detector detectors in some of the police units so the officers can tell if someone has a radar detector in their car. At least that's what a dispatcher friend I knew about 10 years ago told me.

I thought it was a load of BS but then I saw detectors that came on the market that had "stealth" circuitry that somehow circumvented this. In order to stop this, any reciever wishing to be "stealth" would have to be heavily shielded to stop these emissions from the IF circuit, correct?

I also think I've had my old radar detector give false alerts when another car is passing. I'd guess it was because it was detecting the other car's unit, right?

Yes on the first paragraph.

On the second, I thought they used a wider variety of IF frequencies, not better shielding.

On the last, it was likely someone who had a black box with a radar transmitter in it. AKA 'Brake tester'

Anymore, radar is available on some car models. It aids in collision avoidance. Maybe that's what you were picking up, too.

Joe M.

 

[poltergeisty]

Back to my original question.

Anyone know of a filter to block output signals.

 

[Voyager]

Back to my original question.

Anyone know of a filter to block output signals.

You mean block the Local Oscillator signals?

Joe M.

 

[Al42]

Most car stereos use the same IF as most scanners (10.7 MHz).

The recent GRE scanners don't.

 

[N_Jay]

LOL, I do wonder if those radar detector detectors are getting screwed up by the radar built into some cars? (E.G. MB S-Class)

I can see some "important person" getting the third degree from some local yokel, as to where he hid his radar detector! :twisted: :twisted: :twisted:

 

[Al42]

Most scanners I've tested are low injection on VHF, so you would want it PD - 10.7 MHz, although the injection could be on either side.

Actually you'd want it at PD - [the first IF] Mhz. The injection osc. frequency for the 10.7 MHz IF depends solely on the second IF.

You would have to be really careful about building such an oscillator. They find this little black box in your car that generates an RF carrier. Do YOU want to try to explain to them that it has nothing to do with a detonator?

Since RF is none of their business, no. If they want to call in the FCC, that's their call, but the FCC isn't about to respond to check out a part 15 device at the request of the locals unless there's proof that it was used in the commission of a crime.

They may be having the last laugh when they tear your car apart looking for other questionable devices.

Then they'll laugh on the other sides of their faces whren the judge orders them to put the car back in the condition they found it - or replace it if they can't. And there's always the constitutional vioolation involved there. That's always good for a laugh - not on their part.

Then you have to explain to the judge that it was just a joke

Nope - since the local (city, county, state, etc.) court has no jurisdiction in the case, I wouldn't have to explain anything more than that. Just a request for dismissal based on lack of jurisdiction. And, off the record, notice of intent to appeal any conviction - with the assistance of the federal government - which doesn't like to have its legally assigned powers usurped. (It even says so - see PRB-1, PR Docket 91-36, etc.)

Not that any of this is more than moot, since scanners have too many first IFs for the frequency of a signal emanating from the car - a signal so weak, and received for such a short time that it's uncertain anyway - to have any evidenciary value.

 

[Al42]

You are just a bit paranoid.

LOL, lets see less than 100 mw, part 15, that one would be one hell of a probable cause case for searching your vehicle.

Not paranoid - just very cautions of sticking the proverbial crooked stick in the hornet's nest. Do you really think most cops know about Part 15?

Yes paranoid. Do you rreally think the federal government cares whether a cop knows the law or not? If he violates federal law, he violates federal law, and the penalty is the same for him as it is for you. His local badge carries no federal weight.

After 9/11, do you really think they are going to say "well, it's just a Part 15 device, so you can be on your way."? You don't think their finding a mysterious home built transmitter is PC for searching the vehicle?

Your car? They'd have grounds to shred all the metal looking for something hidden beteween the surfaces. My car? They'd have grounds to learn how to wave "bye-bye" as I left with no search having been conducted.

The difference? I know the law, you don't, so you'd keep your mouth closed and allow them to tear your car apart, while I'd hand them copies of federal rulings I always have with me when I'm traveling, and let the local DA have fun reading them - then ask him whether he wants to wave as I leave.

I have radio signals emanating from my car? So I'd like to see the cop's FEDERAL ID - otherwise he's exceeding his jurisdiction - FAR exceeding it. And taking a good chance that he'll retire with no police pension.

The police can't tear your car apart (or even search it) just because they want to. (And "There's a radio signal coming from that car" is "just because they want to". There's no probable cause for a local law enforcement officer to obtain a search warrant on a suspected technical federal violation. And that's all it is, 9-11 or no 9-11. Local police paranoia doesn't constitute probable cause.)

Think about it this way: You are building a device that emits the same frequency as a receiver's LO (with the same IF) on a police frequency. Granted, the range is limited, but let's use the argument that your intent may be to interfere with the reception of transmissions on a particular receiver. Is that reasonable to think that's possible motive? (whether or not it would actually be strong enough to work)

Not without proof - and there can't be any such proof, so no, it's not reasonable, and it's not sufficient cause for a warrant - even assuming jurisdiction, which doesn't exist even if you were intending to interfere with the police department's radios. As far as the law is concerned they're just users, and they have to call the FCC the same as you or I do.

It's like the guy who carrys a plastic gun through the security checkpoints at the airport just to prove it can be done.

Not at all - airport security guards have the legal right (not to mention the job responsibility) to search people who are about to board commercial aircraft. Local police don't have the legal right to enforce federal radio laws.

Again, it's not paranoia - it's sensible caution for a post-9/11 USA.

Giving up your rights for security is worse than paranoia, it's stupidity. Just ask Ben Franklin.

 

[Voyager]

Most scanners I've tested are low injection on VHF, so you would want it PD - 10.7 MHz, although the injection could be on either side.

Actually you'd want it at PD - [the first IF] Mhz. The injection osc. frequency for the 10.7 MHz IF depends solely on the second IF.

Based on the given example of 10.7 MHz IF, I would be correct also.

You would have to be really careful about building such an oscillator. They find this little black box in your car that generates an RF carrier. Do YOU want to try to explain to them that it has nothing to do with a detonator?

Since RF is none of their business, no.

If they have laws against RF receivers (scanners), they are MAKING RF their business - legal or not - stupid or not.

Not that any of this is more than moot, since scanners have too many first IFs for the frequency of a signal emanating from the car - a signal so weak, and received for such a short time that it's uncertain anyway - to have any evidenciary value.

I've detected many scanners successfully - some from quite a distance away. There aren't as many first IF frequencies as you might think. A couple dozen? If that? It's not hard to scan a couple dozen frequencies, as most on the board know.

Joe M.

 

[Al42]

Most scanners I've tested are low injection on VHF, so you would want it PD - 10.7 MHz, although the injection could be on either side.

Actually you'd want it at PD - [the first IF] Mhz. The injection osc. frequency for the 10.7 MHz IF depends solely on the second IF.

Based on the given example of 10.7 MHz IF, I would be correct also.

If 10.7 were the first IF. That hasn't been the case in decades.

You would have to be really careful about building such an oscillator. They find this little black box in your car that generates an RF carrier. Do YOU want to try to explain to them that it has nothing to do with a detonator?

Since RF is none of their business, no.

If they have laws against RF receivers (scanners), they are MAKING RF their business - legal or not - stupid or not.

Sorry, but federal law precludes any such regulation (of RF emanating from cars). Part 15 is a federal regulation - and federal regulations have the force of federal laws, totally preempting local laws attempting to regulate the same thing.

Not that any of this is more than moot, since scanners have too many first IFs for the frequency of a signal emanating from the car - a signal so weak, and received for such a short time that it's uncertain anyway - to have any evidenciary value.

I've detected many scanners successfully - some from quite a distance away. There aren't as many first IF frequencies as you might think. A couple dozen?

Totally blowing "beyond a reasonable doubt". In fact, if there are only 12 IF first IFs in use, I could be scanning any of 12 frequencies, making my "guilt" only 8.3% probable - and the law requires a lot more than that for conviction. Since the department in question knows, or should know, this fact, merely writing a summons based on detecting a legal radio signal emanating from a car constitutes harrassment. Not that any police department has the equipment or personnel to determine whether any particular signal is legal under part 15. And, even if one did, none has the authority to do so. As I've said before, police departments are required to follow the law.

 

[Voyager]

You are just a bit paranoid.

LOL, lets see less than 100 mw, part 15, that one would be one hell of a probable cause case for searching your vehicle.

Not paranoid - just very cautions of sticking the proverbial crooked stick in the hornet's nest. Do you really think most cops know about Part 15?

Yes paranoid. Do you rreally think the federal government cares whether a cop knows the law or not? If he violates federal law, he violates federal law, and the penalty is the same for him as it is for you. His local badge carries no federal weight.

And you think violations don't occur? I would rather be paranoid than ignorant. They happen all the time, and no matter the recourse you may have after the fact, it is still AFTER the fact and you have been put through whatever they deem necessary and prudent.

After 9/11, do you really think they are going to say "well, it's just a Part 15 device, so you can be on your way."? You don't think their finding a mysterious home built transmitter is PC for searching the vehicle?

Your car? They'd have grounds to shred all the metal looking for something hidden beteween the surfaces. My car? They'd have grounds to learn how to wave "bye-bye" as I left with no search having been conducted.

If they tracked an offending signal to your car, and they have laws that apply, and you try to leave without a search AFTER they have determined probable cause, expect to go to jail. You can refuse to let them search your personal property, but ONLY so long as there are not violations in clear view. Since the RF radiated past the confines of your car, it can be deemed 'in clear view' - just as if you had your crack pipe on the dashboard. Then, you can wave bye-bye as you initiate a car chase (assuming you ever get the car moving).

The difference? I know the law, you don't, so you'd keep your mouth closed and allow them to tear your car apart, while I'd hand them copies of federal rulings I always have with me when I'm traveling, and let the local DA have fun reading them - then ask him whether he wants to wave as I leave.

I never said I would do that. But then, I wouldn't antagonize them in the first place.

Do you have a federal ruling that says scanners are legal? If so, please post a copy for everyone. But, of course, I seriously doubt you do.

The police can't tear your car apart (or even search it) just because they want to. (And "There's a radio signal coming from that car" is "just because they want to". There's no probable cause for a local law enforcement officer to obtain a search warrant on a suspected technical federal violation. And that's all it is, 9-11 or no 9-11. Local police paranoia doesn't constitute probable cause.)

Not violation of federal law - violation of STATE law. (or in some cases LOCAL law)

It's like the guy who carrys a plastic gun through the security checkpoints at the airport just to prove it can be done.

Not at all - airport security guards have the legal right (not to mention the job responsibility) to search people who are about to board commercial aircraft. Local police don't have the legal right to enforce federal radio laws.

They have the right to search people for certain PROHIBITED items - weapons, explosives, Etc., not the right to prohibit boarding (using your words) just because they want to, or because they have a toy, or a flexible nail file, or any of the other really stupid things that couldn't do nearly as much damage as a common PENCIL (which they DO let aboard!)

One again, we are talking about STATE laws, not federal. You just don't seem to understand that.

Again, it's not paranoia - it's sensible caution for a post-9/11 USA.

Giving up your rights for security is worse than paranoia, it's stupidity. Just ask Ben Franklin.

I shudder to think what laws we may have in place today should people from that era have been in the same circumstances we are today.

How about the government promoting ATHEISM in all government buildings. It's happening every day, and few are saying anything about it. They aren't supposed to make any laws that promote any particular religion, yet they are doing so.

But anyway, you are AGAIN putting words in my mouth. I never said I agree with all the new post 9/11 laws. But, I understand the need for increased scrutiny - especially when they have evidence that you may be violating the law.

Joe M.

 

[Voyager]

If they have laws against RF receivers (scanners), they are MAKING RF their business - legal or not - stupid or not.

Sorry, but federal law precludes any such regulation (of RF emanating from cars). Part 15 is a federal regulation - and federal regulations have the force of federal laws, totally preempting local laws attempting to regulate the same thing.

So you are saying in your professional opinion that Federal law preempts local or state laws when it comes to prohibiting scanners in cars? If so, you're going to make a lot of friends on the board real quick (if you can prove it). If you can, please do.

Joe M.

 

[kb2vxa]

Hi guys,

Oh boy, you sure know how to hash and rehash, that dead horse must have been beaten to dust by now. (;->) The bottom line is if they don't see it and don't hear it, it doesn't exist. The antenna won't be questioned with all the hams and CBers on the road.

That picture was a JOKE, and yeah, you Mr. Potentate know darn well where I swiped it from. (;->)

Well, if nothing else you're all entertaining, a regular hamfest on line.

 

[N_Jay]

Just out of curiosity;

Has anyone here ever been stopped or questioned about their scanner?

Or is all the worrying about nothing.