STRANGE COMMUNICATIONS HEARD ON HAM RADIO

This is can be heard every day of the day at any hour, almost non-stop. Sounds like the same voices too, but it is of course all unintelligible. Every once in a while a morse code burst comes through, like a repeater ID. Still, I thought that digital trunked communication systems were frequency hopping, whereas this is always on the same frequency of 461.125mhz FM. Anyone who knows what this is, please comment and let us know! It's probably something very simple, but it is definitely more fun to think of it as being aliens!

[PyrodoxLion]

This is voice inversion scrambling, as someone had mentioned in an earlier comment.  The "sqwauk" sound you hear at the beginning of each of their transmissions is MDC1200, which is a data protocol used by Motorola and some other commercial/public safety radios, specifically the PTT ID, which identifies the radio of the person keying up.

I went ahead and cut out the pertinent clips of audio where they were transmitting in your video, then ran a simple Nyquist Prompt filter in Audacity on the audio to "de-invert" it.  While it's not perfect, you can make out what they're saying (for the most part, the one guy talks really quickly and I don't know if I'd understand him in the first place).

The first transmission you hear the guy says something along the lines of "Uhh, security, I wanna know where building 57 is."  another guy responds "Alright, just call me, I'll give you the guy's number."  then another unit responds "Copy that."  the bit in the middle I couldn't quite make out, but then it sounds like another unit calls out a unit ID, sounds like "4143." then the unit that originally replied with "I'll give you the guy's number." responds with "Standby."

The Nyquist Prompt code I used in Audacity is "(lowpass8 (mult 4 (highpass8 s 24) (hzosc 3333)) 2400)"  Then I also ran a Noise Reduction filter in Audacity using a little chunk of the static on the signal as a Noise Profile to clean up the audio a little.

The Morse code you hear is probably the CWID of the repeater they're using.  If you can get a recording of that I could tell you the callsign and who it's licensed to.

461.125 mHz is in the FCC Industrial/Business Land Mobile Radio Service, so this is probably a business operating in your area.

If you're interested I can provide you with the de-inverted audio.

[gunslinger]

what you are hearing is voice encryption...I worked as a Police Officer for 10+ years, and our radio systems had the encryption option...if we wanted to go covert with our communications for sensitive information, etc...we'd say "switch over", and we'd go to the encrypted channel. I'd recognize it anywhere, it sounds like SSB...and you can tell by that "key up squawk" that it's either Police, Fire, Etc.

[Yavor]

This is simply frequency inversion scrambling..the most crude way to hide voice content.

[bunker]

It's an Imperial Probe Droid, duh!

[jeffbailey]

Sounds like an inverted Voice Scrambler.  These are popular in many commercial and public safety radios.  The fact that you hear it 24/7 tells me that it's likely public safety.   It's not digital mode because you wouldn't hear anything resembling voice.   This is scrambler boards in FM Analog.

[rider]

At 1:44 you can hear a distorted "copy that"

[jeffdwyer]

You can clearly hear the MDC (digital Identification) when they key up, then you are hearing analog encryption . (an old simpler form of scrambling ).

[richardbernard]

hey dude I bought a zastone v8 I wanna hear what ur hearing how do I do it

[tonikk]

Oh man it would be cool to have a signal from some totally different kind of reality. Imagine that!

[motoforlyfe]

Could be local law enforcement but from what I've been told its a business frequency

[coondogtheman]

Those data beep sounds are used a lot for police and emergency services for the end of the transmission. As for the voices turn down the bandwidth, listening to narrow band signals on a wide band receiver will give that effect.

[motoforlyfe]

I think you are right about it being voice inversion. Pretty neat how it works.

[erics]

 This is an old method of scrambling called inversion scrambling, The squawk you hear is ANI or automatic nummeric ID which is just a data burst sent out when the mic is keyed so that the others on the channel know who is transmitting. The dispatcher or even other radios will display the unit ID number when the radio matches this data to a database of ID numbers stored in the radio's programming. More than likely it is a police dept or taxi company. Who else operates 24/7?  It is scrambled to keep scanner listeners or other taxi companies from knowing what is being said. If it was digital all you would hear is noise. At least one other person had it right.

[kdps]

It is a UHF business repeater using Motorola MDC1200 radio ID signaling at the beginning of the transmissions along with a simple voice inversion analog scrambler. Older technology but still effective to prevent casual monitoring. Most likely a local Taxi or Towing service. Thanks for posting the video.

[goodyear]

What is the make and model description of your hand held radio.

[ianlombardo]

461.125 is in the UHF Public Safety Pool. FCC regulations state that the operating station must transmit it's call sign (identity) every hour

[motoforlyfe]

That's two votes for voice inversion, that must be it!

[Dusty]

What kind of radio is that? It don't sound like digital encryption. Encryption is more garbal. It sounds like a Upper side band or lower side band. LSB/USB always sounds like aliens when its not tuned. Even when it is tuned they sound like they are talking after inhaling some helium.  

[Jr-fmye]

what should i know to find the frequency on the radio

[motoforlyfe]

I have tried looking it up but haven't found a whole lot. Pretty soon I will be seeing about decoding it...have not gotten to it yet but I will be looking for some kind of software to do so. Thanks!