Trying to get T4Win to work

[tfr]

Hello,

I have been trying to squeeze some info out of a local police/FD radio system. I know it's an EDACS Network that uses AEGIS - I know I'm not currently able to listen to the voice communication with AEGIS, but should I be possible to extract the info out of the control channel?

Also, they actually seem to have two control channels - at least in the frequency range dedicated to this system there are two frequencies that carry a constant signal - a similar one.

But T4Win hasn't given me any results so far. The waveform is displayed - meaning the info must be getting to T4Win. Control/Sampling checkboxes are selected as instructed. Have tried both with and without the "Invert" checkbox, but the status bar remains at "Decoding rate 0.0 Motorola".

Any pointers?
Thanks.

 

[Forts]

Which system is it that you are trying to monitor? Perhaps that will help someone shed a little light on it for you. I have an EDACS system near me that uses AEGIS digital as well... and neither ETrunk or T4Win have any problems following it. Are there any analog talkgroups on the system? Are you able to follow it with a scanner? Perhaps they are using ESK (EDACS Security Key).

 

[tfr]

Which system is it that you are trying to monitor? Perhaps that will help someone shed a little light on it for you.

What exactly do you mean by that? I know it's an EDACS system using AEGIS. Are there any other parameters I should be aware of?

Are there any analog talkgroups on the system? Are you able to follow it with a scanner?

I've stumbled upon analog responses 2 or 3 times - I don't know if they were just reverted to analog for some reason or are there any analog talkgroups on there. I stored all the frequencies in a bank one evening and listened to it for couple of hours before the digital data noise started driving me nuts, but didn't catch any more analog conversations during the process.

 

[ve3tej]

Could you tell us which system you are trying to monitor?

What city it is in or a control frequency.

In London they have an EDACS system using AEGIS and T4Win does work.

If you could give a few more information other people might be able to help.

 

[tfr]

ve3tej,

It's the joint EDACS system in Tallinn, Estonia - used by both the police, fire departments and ambulance.

If I assume that they are running the ESK, which seems to be an 8-bit number (00-FF), is it just the trouble of manually adding a system in the "Database" part, setting it to EDACS96 (which it is, comparing the control channel with the samples provided in the Wiki part of this site, plus the fact that it's around 420MHz, not 900), and brute-forcing through the 256 possibilities? If so, how long should I wait on each possible combo before I should be seeing some positive decoding rate given it seems to be a pretty busy system?

Also, is there a way to tell T4Win that I'm only trying to listen an EDACS96 system and it can skip trying the rest?

 

[N7YUO]

As a new user of T4Win, I had trouble geting it to work. I had a waveform, but that's all. I discovered that after I selected a receiver & started it (waveform) I had to click on Database and select the trunked site I had tuned, Then I had to go back to the toolbar and click on Activity.
The frequencies would then display. The local site serving Salt Lake County has about 20 freqs, and
they won't all display unless I enlarge the 'window' of T4Win.

 

[tfr]

I tried the MrGadget way now - still no luck.

Can anyone confirm my earlier logic - can I just do Insert > Radio System, add an EDACS96 system, and brute-force through the 256 ESK key combinations? Or am i completely off thinking along these lines?

 

[SCPD]

Can anyone confirm my earlier logic - can I just do Insert > Radio System, add an EDACS96 system, and brute-force through the 256 ESK key combinations? Or am i completely off thinking along these lines?

If you are still getting a decode rate of zero, then you've got bigger problems.
Can you post a screen shot of the waveform? That might give us a clue. Have you successfully used the radio and/or software to monitor other systems?

On an ESK system with good clean signal, T4Win will display "100%" decode rate but will not be able to provide call information (or erroneous information). The next release of UniTrunker may be able to help. First, I'd work on getting your decode rate up to something useful like 80% or better.

Once you get to the point of actually getting a useful decode rate, you can run EDumper (included with Trunker), Dumper (T4Win version), or Packets (included with UniTrunker) to capture some control channel data. If you post an example of the log output here, one of us can make a guess as to the correct ESK setting.

-rick

 

[tfr]

Rick,

here's a screenshot of T4Win in action:

Also, here's a bunch of other shots of the waveform:

And finally, here's a 2 minute .wav file (1.2MB) of the control channel:

http://tfr.cafe.ee/kama/edacs.wav

 

[tfr]

Oh, forgot this q:

Have you successfully used the radio and/or software to monitor other systems?

No, there's no other trunked systems around me that I'm aware of. The scanner (Icom IC-R3) is serving its duty listening to analog frequencies just fine, however.

 

[Jay911]

As far as I know, that waveform is your problem. It needs to look 'square' on the tops and bottoms. Is your radio tapped for discriminator output?

 

[SCPD]

I think Jay's assessment is correct. That waveform is either (1) a very distorted EDACS control channel or (2) not an EDACS signal (or Motorola or MPT1327 signal for that matter).

The only signal that can be decoded using direct speaker or headphone audio is MPT1327. For EDACS and Motorola you need to "tap" your radio to get at the signal coming out of the radio's FM discriminator circuit - just before it gets filtered (which - while fine for listening audio - causes distortion for digital signals).

The reason I mention this is that it isn't clear to me that your radio or "signal source" is providing discriminator audio or filtered audio. If you haven't added a discriminator tap to your IC-R3 ... here's some info that may help.

http://mods.dk/view.php?ArticleId=2856

-rick

 

[tfr]

Okay, thanks - it definitely isn't modded for discriminator audio.

But before I run to my nearest friend with a soldering iron (this is one of the things I steer well clear of myself), I also own a RadioShack PRO-64 and a good friend of mine owns an AOR AR8200 MKIII and an Uniden SC200.

Is any of those three latter usable without modding or significantly easier to mod than the R3?

 

[tfr]

Thanks once again - discriminator was the keyword. After trying it with a modded radio - it works like a charm, there's even no ESK key on the control channel.

BTW, can T4Win make a difference between a clear digital and a DES-encrypted digital channel? If the column says "Digital", is there still a chance the DES encryption is in use?

 

[Forts]

From what I've seen, neither ETrunk nor T4Win can tell you if an EDACS digital talkgroup is encrypted or not. I've monitored a few different EDACS systems near me with both digital and digital/encrypted talkgroups and they all show up the same in the software. So the short answer? No, it can't tell if encryption is being used or not.