Does the other party know they're being scanned ?

[Pr0ph3t]

Hi everyone,

When scanning with my baofeng for example I'm running into frequencies where I'm hearing some odd things, it's almost as if they know someone is listening. is that possible ? Fyi I have duplex off on all the channels and vox is off as well.

Ran into this:
"
This is the basic flaw in your thinking. Both RADAR detectors and scanners ARE "transmitting" something. They all have local oscillators, and there is some signal there which can be detected.

Most RADAR detectors are sitting in someone's windshield and built in a plastic case. They are, by comparison "easy" to detect. Modern scanners have more than one local oscillator, and usually not sitting in your window, which creates some challenges to detect them.

The answer to your original question is yes. But, it is not something that can be done in a practical manner. To add to the complexities, different brands and models of scanners have different local oscillator frequencies. A device could JUST detect these frequencies, but then it would be an even larger step to try and figure out if those signals were coming from an iPod, iPad, other radio or a long list of other devices.

We had a long thread on this topic a couple of years ago. It was called RADAR detector detector or scanner detector or something like that. "

Does this still stand ?

 

[res5cue]

There are many times I have come across some odd conversations when scanning. Mostly on the FRS and GMRS and MURS channels. They think that no one else can hear. There are some Public Safety frequencies that they think no one else can hear them and the dumb stuff they say.

 

[Pr0ph3t]

There are many times I have come across some odd conversations when scanning. Mostly on the FRS and GMRS and MURS channels. They think that no one else can hear. There are some Public Safety frequencies that they think no one else can hear them and the dumb stuff they say.

Ok but they don't know I'm on the chan yes ? Like one channel I ran into they were saying 'we're asking the other party to hang up' but I missed the beg and end of the transmission so it made me paranoid lol

Then they went digital and started sending a morse like sound and it stopped

 

[RaleighGuy]

Ok but they don't know I'm on the chan yes ? Like one channel I ran into they were saying 'we're asking the other party to hang up' but I missed the beg and end of the transmission so it made me paranoid lol

Then they went digital and started sending a morse like sound and it stopped

Any person using a radio should assume someone else is listening, it is no secret, but unless you press the transmit key on your Baofeng (which is NOT a scanner, it is a transceiver, even though it will scan through the channels) they won't know who it is.

 

[Pr0ph3t]

Any person using a radio should assume someone else is listening, it is no secret, but unless you press the transmit key on your Baofeng (which is NOT a scanner, it is a transceiver, even though it will scan through the channels) they won't know who it is.

Thank you very much I appreciate the response. I was scared maybe the TX is stuck somehow but no seems to work fine. Duplex is disabled though on all the channels I'm scanning though and I don't have the input freqs inputted obviously. Just being paranoid.

@res5cue Yes thank you transceiver. That's why I specifically mentioned Baofeng in case scanners had some type of protection. (Which obviously is off base thinking I think)

 

[mmckenna]

1. Really good idea to disable transmit on any and all frequencies/channels you are not licensed for. You never know who may get their hands on your radio.

2. Modern radios do have a local oscillator, but it's very very low powered, and steps are taken to limit any emissions outside the radio (covered under Part 15 of the FCC rules). Yes, someone could receive that, but they wouldn't necessarily know what you were listening to. And, they have to be really close.

 

[Pr0ph3t]

1. Really good idea to disable transmit on any and all frequencies/channels you are not licensed for. You never know who may get their hands on your radio.

2. Modern radios do have a local oscillator, but it's very very low powered, and steps are taken to limit any emissions outside the radio (covered under Part 15 of the FCC rules). Yes, someone could receive that, but they wouldn't necessarily know what you were listening to. And, they have to be really close.

Ok so most likely coincidence I doubt they were close. It's happenned a few times I've been doing this for a few years. But before I was just messing around I've taken a much more 'sophisticated' approach now (which is utterly laughable comparable to what you experts do but a huge step for me) and so I'm running into channels I wasn't before so you know, makes you raise an eyebrow, what if VOX is on and I don't know it, what if my transmit is stuck or something I dunno. (no and no I do everything through chirp)

 

[mmckenna]

Ok so most likely coincidence I doubt they were close.

Yeah, some of our Motorola XTL consolette radios will get picked up by my handheld when I'm at our dispatch center, but I have to be standing right next to the radios for it to happen. And then it just barely breaks squelch. Taking a step backwards and it goes away.

In addition to making sure you have transmit disabled, it's also wise to keep a time-out timer set on your radio, that way if you do accidentally bump the transmit button, it'll time out. -ALL- the radios I run at work (500+) all have a time out timer on them.
And VOX should be disabled, that stuff will always get you in trouble.

 

[Pr0ph3t]

Yeah, some of our Motorola XTL consolette radios will get picked up by my handheld when I'm at our dispatch center, but I have to be standing right next to the radios for it to happen. And then it just barely breaks squelch. Taking a step backwards and it goes away.

In addition to making sure you have transmit disabled, it's also wise to keep a time-out timer set on your radio, that way if you do accidentally bump the transmit button, it'll time out. -ALL- the radios I run at work (500+) all have a time out timer on them.
And VOX should be disabled, that stuff will always get you in trouble.

Yah chirped the living hell out the uv82. Timeout is set to 120 though for SSTV transmissions *guilty sidelook* 60 seconds was too close. Also I've disabled duplex on everything except emergency channels and repeaters, stuff like that. (and by emergency I mean like search and rescue )

 

[hill]

You can still transmit on it as simplex channel. Going forward there is a setting within Chrip for each channel that say something like Toff. This disables transmit on these channels, so no way to accidentally key up the radio.

Every radio service has an issue with stuck mics from time to time. It very easy for the end users to sit on the mic or have an HT on their belt have the PTT pushed when sitting.

Going forward it's best to be proactive and disable transmit on any frequency you arn't authorized to operate on.

 

[Patch42]

Most RADAR detectors are sitting in someone's windshield and built in a plastic case. They are, by comparison "easy" to detect.

Many years ago I had a radar detector that was very good at detecting other radar detectors. One night I was driving on an almost deserted country road. There was just me and one car that was behind me. The car behind me starts to close the distance between us and my detector goes off. I immediately slow down, the car behind slows down and falls well back. There's literally nothing around us. The detector stops chirping and I eventually speed up again. The car behind speeds up and closes the gap. Detector goes off. I slow, he slows and again falls back. We did this about four times before I was sure our detectors were setting each other off once they got close enough.

 

[a417]

I slow, he slows and again falls back. We did this about four times before I was sure our detectors were setting each other off once they got close enough.

...or it was a vehicle doing differential speed (i am sure there's a snazzy sounding name for it, i never bothered to learn it) radar. I'm sure if they turned on their patrol lights it would have made it obvious.

Their unit has a radar (sic) gun, and it measures the difference between the patrol vehicle and what the radar unit says your vehicle is doing, and shows it on the unit. Many, many years ago when I had access to a project 54 car - that was one of the displays on the terminal. I am quite sure that modern units do this integrally now.

 

[Patch42]

It definitely was not a police car. It was just some guy on a deserted stretch of road wanting to drive faster than I was. Every time he'd close to the distance where he was about ready to pull out and pass, my detector would go off and he'd hit the brakes. The fact that my detector went off and he reacted the way I would have if there hadn't been a car right on my tail eventually made it obvious what was happening.

 

[chrismol1]

I wonder, a bunch of new cars have all these safety features lane change detect and and teslas autopilot. These have to emit some sort of infrared or laser, or radar. I dont have a radar detector but was looking into one years ago, just for fun to spot a random smokey even though I dont speed and a bunch of reviews mentioned random detection, even LED billboards would set them off, do the new detectors go off at random all the time?

 

[Ensnared]

Some of the more expensive high-end radar detectors come with stealth shielding.

Undetectable Radar Detectors - Buyer's Guide

Which radar detectors are undetectable by police in 2019?

 

[pinballwiz86]

Some of the more expensive high-end radar detectors come with stealth shielding.

Undetectable Radar Detectors - Buyer's Guide

Which radar detectors are undetectable by police in 2019?

Yep, for the states were radar detectors are illegal.

 

[wtp]

back when scanner used either 10.8 or 10.7 local oscillator, i would park IN the parking lot of various police agencies in new jersey and listen for the tell tale 'beep' on their regualr frequency.
then i would do the math for a double check and then look around slowly for any others.
mag mount antenna, squelch off and i would take my lunch hour there.
it worked in many instances.
i moved in the mid 90's to Florida.
FHO used 154.68 at the time and i would keep 143.98 and 143.88 in one of the couple of scanners that i carried.
(pro32, pro34 and a freq counter). one day coming home i got the steady dead carrier and it was an undercover FHP in a ford mustang NEXT TO ME, i just smiled and he kept going. i would say he had a scanner in the car and that i was not picking up his work radio.
if i recall they used 154.665, .68 and .695 in different areas

 

[krokus]

Yah chirped the living hell out the uv82. Timeout is set to 120 though for SSTV transmissions *guilty sidelook* 60 seconds was too close. Also I've disabled duplex on everything except emergency channels and repeaters, stuff like that. (and by emergency I mean like search and rescue )

What are you calling duplex?

 

[nd5y]

What are you calling duplex?

In CHIRP software "Duplex" is the column that controls a memory channel's transmit frequency. It can be be set to +, -, split, none, or off.

 

[jonwienke]

In CHIRP, setting duplex to OFF disables transmit on a channel. It's an odd way to do it, but it works.