MDT decoding

[slidder]

hi,
i was wondering if/when i come across a MDT frequency, what will it sound like? AND also would the channel ALWAYS be making noise (like a control channel on a Motorola system?) or will it only make noise when certain data is being sent (calls to patrol unit , queries,etc.)?
Also any other info on MDT stuff would be great i have tried searching but only found a program called "listenMdt" from '98 and i am in Canada.

thanks

[N_Jay]

Originally Posted by slidder

hi,
i was wondering if/when i come across a MDT frequency, what will it sound like? AND also would the channel ALWAYS be making noise (like a control channel on a Motorola system?) or will it only make noise when certain data is being sent (calls to patrol unit , queries,etc.)?
Also any other info on MDT stuff would be great i have tried searching but only found a program called "listenMdt" from '98 and i am in Canada.

thanks

There are many formats of MDT data.
Some transmit constantly, others do not.

[jason_58201]

our 460.xxx mhz mdt sites around here sound like a higher pitched buzzing that only comes out in bursts.

[wogggieee]

A lot of the ones around here use the sprint wireless broadband cards in their laptops which makes them unmonitorable. Or atleset very difficult.

[KB9NLL]

Originally Posted by wogggieee

A lot of the ones around here use the sprint wireless broadband cards in their laptops which makes them unmonitorable. Or atleset very difficult.

sprint wireless is a little different than mobile data terminels. I guess it's a type of but MDT's generally don't go through cellular service providers. thats more for wifi internet not dispatching and police reports right?

MDT decoding
In the U.S. I'ts Illegal, is or at least was possible, and has been done to hack into police mdt's. around here they use vhf and uhf frqs. in populated areas otherwise they don't have them at all- no availability. Theres some trucks that use satellite mdt's.
Entry's in the database would have TELM for telemetry at least for the U.S.. Look it up and listen or ask in the Canadian forums.

[N_Jay]

Many departments use commercial data services (Sprint, Verizon, ATT, etc>) for MDT service.

Many others use private data systems on LMR channels.

[jimyleg]

What model mdc does a p25 system use in Mn?

[gmclam]

Originally Posted by slidder

hi,
i was wondering if/when i come across a MDT frequency, what will it sound like?

They have different sounds. They used to sound a lot like a computer modem, as many used "packet radio".

When they first went on the air here (circa 1975), all you needed to do was take the audio and put it into your modem set to 1200 baud. My how things have changed over the years. Too many protocols now to even talk about them generically.

[hotdjdave]

A few years ago, I downloaded a program (free from the internet) that supposedly decoded over-the-air data. I fed the audio from my iCOM IC-PCR1000 receiver through the sound card on my computer. I couldn't get it to work for MDT data, so I am not sure if it does or not. It was able to decode other types of data (SSTV/FAX/WXSat/etc.). I don't remember the name of it. I think I got the info from a thread here at RR.com, so you may want to do a search.

[Tweekerbob]

This I believe was called MDT Monitor. It actually does work, but you need a MDT 4800 (I think) system. It needs a disc. output or the PC-1000 packet output.

The sacramento county MDTs were on this just up until a year an a half ago; so we could monitor Sheriff and other traffic. Meanwhile the SD did upgrade their equipment, and for what I know, they probably are using a commercial carrier for their data traffic. So like 99.x% of the agencies out there, they have moved on to more (very much more) sophisticated systems and no longer use MDT 4800.

If you do a google search, you can probably find the software. The real challenge will be finding an agency which still uses it.

As a footnote, the podunk rural county I live in has had commercial data services for at least the last three years. This allows the deputies to keep up with their craiglist call girls and renew their penthouse subscriptions all the while receiving "important" law enforcement info.

[Bill_White]

Originally Posted by slidder

i was wondering if/when i come across a MDT frequency,
what will it sound like?

There are some audio samples here:
Digital*Modes*Samples

[mattman100]

I have been hearing lots of talk of many different software's to decode this type of MDT format, but all the links are dead. If anyone has access to MDTW1234, ListenMDT, MDTMon, Winmdt, anything that can decode this data type I would greatly appreciate the help. Thank you very much, and Merry Christmas!