Trying to decode MOTOTRBO--Need lots of help

[W4UVV]

First I am not a teckie but I am fairly profiicient with computers and scanners usually being successful with most things I attempt. I have mast mounted preamps on a number of Scantennas tower mounted. I am located in central Va. and have excellent signal ground wave coverage. I have several R7000 analog receivers, a PSR600 and 4 996XTs. I programed the 996XTs for most of the radio systems in Va.

MOTOTRBO is beginning to appear. One rural county SO now uses it. Tuning a R7000 on UHF I am receiving two very strong area signals that as best as I can determine are MOTOTRBO.

I have modified my R7000s for discriminator tap (unfiltered audio). I am an Win XP OS baseline person. I do have a Windows 7 computer I acquired recently because it was a good deal but rarely use because of software incompatibilty issues involved with Windows 7 executing older software which represents most of what is on my desktop XP. I know the R7000 is an analog receiver. After spending most of yesterday reading posts on this forum to the point of mental fatigue and trying to understand them, I decided to give it a try.

I was encouraged to read DSD was ported to a Windows 7 environment. I downloaded it from the Wiki site link and to my surprise after tuning to a strong area MOTOTRBO signal on 461.5125 mhz. I am receiving audio.....mushy audio. I almost can understand what is being said. The audio sounds like SSB on the wrong side. My first impulse was to change the polarization of the signal. Ok. How do I do that?
I have one executable file and one bat file for Windows 7. They are "dsd.exe" and "PROVOICE.bat". That's it...no user software selectable options like I have seen posted. I assume that software is being run in MS DOS. I am using "line input" to the sound card. The signal is quite strong. The mode setting is "NFM". The R7000 has excellent frequency stability.

Assuming these parameters are correct but using the R7000 is not acceptable, is the issue because I am not using a 996XT unfiltered audio? If so that brings up another problem. In the past I had no problem modifying a BCD796 using a .01mF capacitor in line at the discriminator tap point on the pc board. However, when I attempted to modify a 996XT at the two labeled "DISC" pc board tap points I did not receive any audio output. One tap point clearly marked is on the bottom of a pc board and the other on the top pc board near IC3. I received no audio either with the capacitor removed. Obviously I did something wrong and failed to find the correct tap point. Can anyone provide me the correct location tap point for the 996XT? I was not able to locate the information browsing Wiki. I may have missed it.

Any helpful comments appreciated.

Remember, I am not as advanced technically as many of you are so please bear with me. Tnx.

Attached are 3 screen captures. Pictures 1 and 2 have little audio but frequent data transmissions on 463.6325 mhz. Picture 3 is the one where now as I type mushy audio has been almost constant on 461.5125 mhz.

 

[ilgrant]

dsd -h will give you all the options available. The command for reverse polarity on Trbo is dsd -xr.

Someone else will have to chime in on the R7000 and 996xt tapping. But you will need unfiltered audio (i.e. discriminator tap).

 

[W4UVV]

I have no user setup options using Windows 7 OS

Tnx for the reply. In my post as I stated I have two unzipped programs. One is "dsd.exe" and the other "PROVOICE.bat". When I run "dsd.exe" in Windows 7 it immediately begins attempting to decode. I do not have any user setup options. Does "dsd.exe" have to be installed and executed in MS DOS? I have had a discriminator tap on the R7000 for years that works fine. For several years I have used a standalone CTCSS decoder interfaced with no problem.

I loaded the most active frequency 461.5150 mhz. to the 996XT. When "digital" was selected as the type of audio it did not recognize the signal. However, when "ALL" was selected it recognized it full scale. Attempts using various outputs to the Windows 7 line in including using a RS232 9 pin Level 2 signal slicer did not work.

Using the R7000 the unfiltered audio inputted to the Windows 7 attempts to decode. The audio I am hearing sounds clean but mushy similar to the wrong sideband selected on a SSB signal. Since I have no user set up options available to change, how do I invert the signal?

Searching RR posts/Wiki for detailed help so far has not been productive.

Until someone can help me on a couple of subjects I'm "dead in the water".

John

 

[racingfan360]

John...your screenshots suggest you've actually got the right polarization already.

To change it:
Asume your dsd.exe is located in the folder called dsd located at: C:\User\User\dsd

Go to Start>Command Prompt
At the C:\User\User\ prompt, type: cd dsd then enter
At the C:\User\User\dsd prompt, type dsd -xr then enter
This should then start decode inverted.
CTRL+C to exit back to command line prompt
dsd -h to enter help options

Trying running dsd -fr (ie DMR decode only) might help you a bit.

IMHO, the two most significant factors for improving decode quality are (a) a better signal quality/strength coverage and (b) a better soundcard that samples at least at 48khz, coupled with a more powerful pc (especially for running the windows version of dsd).

To give you an idea, my dual boot netbook runs near perfect dsd decode when running the linux version, but the windows version (so same spec/soundcard etc) gives me quite poor results.

HTH, Jim

 

[racingfan360]

Sorry John.....just checked out picture 3 again: this DOES look like you've got the polarization wrong (I assume it decodes as voice all the time, no data decodes, all sounds garbled: if so, it's the wrong polarization). picture 1 and 2 look ok for polarization.

Jim

 

[W4UVV]

So close and yet so far

Sorry John.....just checked out picture 3 again: this DOES look like you've got the polarization wrong (I assume it decodes as voice all the time, no data decodes, all sounds garbled: if so, it's the wrong polarization). picture 1 and 2 look ok for polarization.

Jim

Tnx. for the reply Jim. I don't know how else to say it. Again, the Windows 7 software for MOTOTRBO and PROVOICE does not provide the user any option for changing anything in "dsd.exe". From reading the Read Me file and Wiki documentation I think "dsd.exe" for Windows 7 is a piece of software significantly different than Linux version which allows some user changeable settings. When "dsd.exe" is executed in Windows 7 OS or in MS DOS the results are the same. Immediately upon execution the program checks for the valid input and output devices (i.e, audio input/speaker output) and then attempts to decode MOTOTRBO. I cannot change anything. According to the Read Me file for MOTOTRBO the Windows 7 version default is a positive polarity. There is no data decoded. It is all audio apparently on the wrong polarity.

I created a MS DOS folder in my Windows 7 computer called "DSD" on C root drive. I successfully copied the two required files "dsd.exe" and "cygwin1.dll" to that folder. I tried using "dsd-xr" and and renaming to "dsd-xr.exe" and received the same error message from MS DOS stating it was an unrecognized command, which I suspected would be the case. I find it difficult to believe the programer compiled the software for Windows 7 and made no provision for the user to change the signal polarity. I wish he had compiled two versions, one for positive polarity and the other for inverted polarity.

However, the "dsd.exe" program is neat in another respect. It immediately ids a P25 transmission and attempts to decode it. The MOTOTRBO signal I am testing on 461.5125 mhz. is quite strong and appears to be two sectioned. The audio, although mushy, sounds clean and occasionally I can almost understand a word. I keep catching myself from selecting the "SSB" switch on the R7000 to change the SSB mode for correct reception. The mode selected is NFM and the audio peaks range from from 461.5082 mhz to 461.5192 mhz. centered on 461.5125 mhz. FM mode will not work correctly.

I don't know what else to try. Years ago I ran Trunktracker using a level 2 data splitter and the software would allow me to change the signal polarity but "dsd.exe" for Windows 7 won't.

Attached are some screen captures showing the software downloading, unzipping and opening for Windows 7 I downloaded from the Wiki link. The "README" file also is attached.

If anyone has been successful in using the Windows 7 "dsd.exe" for receiving MOTOTRBO I would like to hear from him.

Tnx. again for trying to help.

John

 

[ilgrant]

John-

In Windows dsd is a command prompt program. It is not a Windows program although it will run in Windows.

The options are set when you run the program such as

dsd -xr

where the -xr is the option. The program doesn't allow you to change the options while it is running.

You must be in the command window before you run the program. For your specific system...

Go to Start>Command Prompt
Type cd c:\dsd\dsdforwin <enter>
Type cd dsd -xr -mg <enter>
This should then start decode inverted.
CTRL+C to exit back to command line prompt
dsd -h to enter help options

 

[W4UVV]

I'll try again

John-

In Windows dsd is a command prompt program. It is not a Windows program although it will run in Windows.

The options are set when you run the program such as

dsd -xr

where the -xr is the option. The program doesn't allow you to change the options while it is running.

You must be in the command window before you run the program. For your specific system...

Go to Start>Command Prompt
Type cd c:\dsd\dsdforwin <enter>
Type cd dsd -xr -mg <enter>
This should then start decode inverted.
CTRL+C to exit back to command line prompt
dsd -h to enter help options

To recap what I did:

I made a folder in MS DOS C root drive called "DSD"

Via a thumbdrive I copied "dsd.exe" and "cygwin1.dll" files successfully to this folder. Are you saying I should have copied only the unopened folder "dsdforwin" and then used the MS DOS commands you listed vice the individual opened "dsd.exe" and "cygwin1.dll" files?

If so I will try your method. Tnx.

 

[W4UVV]

No Luck

John-

In Windows dsd is a command prompt program. It is not a Windows program although it will run in Windows.

The options are set when you run the program such as

dsd -xr

where the -xr is the option. The program doesn't allow you to change the options while it is running.

You must be in the command window before you run the program. For your specific system...

Go to Start>Command Prompt
Type cd c:\dsd\dsdforwin <enter>
Type cd dsd -xr -mg <enter>
This should then start decode inverted.
CTRL+C to exit back to command line prompt
dsd -h to enter help options

I have the "dsdforwin" folder in a "downloads" folder on thumbdrive E in the Windows 7 computer. When in MS DOS C directory "DSD" and attempt to copy the "dsdforwin" folder from drive E "downloads" folder to C drive directory "DSD", the Windows 7 version of MS DOS will not allow copying of the unopened folder "dsdforwin". I MUST copy each file individually or not or all contained in "dsdforwin" folder. When using the MS DOS command within C: "DSD" copy e:\downloads\dsdforwin" I am asked if I wish to copy each individual file contained in "dsdforwin". My choice for each file is "No/Yes/All". The "NO" selection results is DOS ignoring the copy command. "YES" copies it. "ALL" copies all files in the "dsdforwin" folder and I wind up with the same individual files I previously had in the "DSD" directory.

Using the MS DOS command "dsd-xr-mg(enter)" within C: DSD results in the MS DOS error message.

Would you PM me providing a phone number I could call and possibly try another option or tell me what I am doing wrong? Tnx

John

Screen capture attached showing MS DOS will not allow the copy of the "dsdforwin" itself. I must copy each file contained therein individually.

 

[ilgrant]

You are close. You need to have a space between the dashes.

dsd <space> -xr < space> -mg

dsd -xr -mg

 

[AZScanner]

An easier method would be to right click on Provoice.Bat, select Edit and open it in notepad. You will see the following:

dsd -i /dev/dsp -o /dev/dsp -fp

Change this to:

dsd -xr -mg

and then go file->save as->Mototrbo.bat (make sure in the Save As Type dropdown below the filename you select All Files first before clicking Save)

Now you can just double click the new batch file you created and voila, you should be all set.

I love DSD, it's a great program. I'm still muddling my way though the source code. I would LOVE to make an RD/LAP decoder out of it, but C is greek to me. Still, it'd be fun to be able to pull it off.

Good luck!
-AZ

 

[W4UVV]

A little success

You are close. You need to have a space between the dashes.

dsd <space> -xr < space> -mg

dsd -xr -mg

Ok. I understand now how to use the menu options from the "dsd -h" list. I tried inverted MOTOTRBO signal and it did not help. I selected MOTOTRBO only and tried both positive and inverted signal with more discernible mushy audio on the positive side. Maybe what I am trying to listen to is not a MOTOTRBO signal but dsd seems to like it. It sounds to me like a SSB signal multiplexed onto a NFM RF base signal and is very frustrating as I almost can understand a word occasionally although SSB like sounding mushy. I can tell when a female or male is talking. Although mushy I just almost understood a male say "10-4".

I would like to speak with someone who successfully is receiving MOTOTRBO and determine what if anything I still am doing wrong.

Thanks very much for your help and the others who posted help info. I really appreciate it as I am a slow learner. The county sheriff I mentioned recently changed to MOTOTRBO is about 100 air miles from me. But his tower site location is on a mountaintop community repeater location. From that mountaintop site I currently receive a Va. state P25 transmission I can decode on my 996XT and also have heard the SO transmissions which are infrequent and share 154.8000 mhz. with a couple of other analog users. I'll give that a try. I tend to be persistent.

Thanks again...this is a new area of monitoring for me.

John

 

[racingfan360]

John - based on what you have posted, I really do think you are listening to MotoTRBO.

A few suggestions:
1. can you post a screenshot of the command line screen running dsd when you decode/hear this 'mushy' voice? If you are seeing SYNC with +DMR or -DMR, modulation as GMSK and a mix of some DATA, Slot Idle and VOICE decodes like your screenshots 1 and 2 then you have MotoTRBO.

2. When you say you have a strong signal, exactly how strong is it? You do need a good clean signal for decodes in my experience. But if you're absolutely on top of the signal and its booming out, try reducing the strength of the signal input.

3. What spec of PC are you using, and specifcially what's the sampling rate of the sound card. The better the spec and the higher the sampling rate = more success with DSD.

4. There is a possibility the signal is encrypted, but lets rule out these few things (as above) first.

Jim

 

[W4UVV]

monitoring info for MOTOTRBO

John - based on what you have posted, I really do think you are listening to MotoTRBO.

A few suggestions:
1. can you post a screenshot of the command line screen running dsd when you decode/hear this 'mushy' voice? If you are seeing SYNC with +DMR or -DMR, modulation as GMSK and a mix of some DATA, Slot Idle and VOICE decodes like your screenshots 1 and 2 then you have MotoTRBO.

2. When you say you have a strong signal, exactly how strong is it? You do need a good clean signal for decodes in my experience. But if you're absolutely on top of the signal and its booming out, try reducing the strength of the signal input.

3. What spec of PC are you using, and specifcially what's the sampling rate of the sound card. The better the spec and the higher the sampling rate = more success with DSD.

4. There is a possibility the signal is encrypted, but lets rule out these few things (as above) first.

Jim

Jim, here is a recap of my setup. I have a number of scanners and radios. I have a 100 ft. tower with mast mounted preamped Scantennas at about 120 ft. I have very good ground wave reception. I can talk over 2/3 of Va. on 6 meters USB. The equipment I am using is one of several R7000s I still use for analog reception. All have been modified for discriminator (unfiltered) audio output. I take the output of the R7000 and input it via "line in" to the Windows 7 computer. I am a Win XP preferred user because the incompatiblity of Vista and Win 7 OS. But Windows 7 OS has some attractive advantages but I rarely power up the Windows 7 computer. I manage to "stumble" around in Win 7 software but it drives me crazy trying to be a computer "nanny" prohibiting from navigating/wireless lan hookups.

Per Belarc Advisor:

System Model Dell Inspiron 5700 00
OS Windows 7 Enterprise (x64)(Build 7600)
Processor 2.8 Ghz. AMD Athlon II X2 240
2816 Installed memory (RAM)
80 GB NTFS HD
ATI HD Audio Device
Bus Clock 200Mhz.

I have no idea of the speed of the sound card but since the audio device is HD I assume it is worthy.

So far I have ided 4 uhf signals I think are MOTOTRBO. At least DSD likes them. The strongest is on 461.5150 mhz. @ S12-15 averaging S9+3. The center peak of the signal is 461.5135 mhz. which is weird. Maybe it is because there are two channels? I cannot find a licensee in my general area on the FCC database but that doesn't stop some people from operating. From experimenting the 461.5150 mhz signal audio reception is best on the positive signal side. The audio sounds clean but is mushy like SSB on the wrong side.

I had thought about encryption but since I have never heard a MOTOTRBO signal, I have nothing with which to compare it.

Whomever the users are go from morning to night with frequent mushy audio comms.

Dsd is very fast and the screen activity flies by when active. Attached is a screen shot of 461.5135 mhz. first two with positive polarity and the second two with inverted polarity signal input. When inverted polarity is selected the mushy audio is not as loud and seems like it is parceled into time segments like packets. The mushy audio does not sound like that on the positive side. it is uninterrupted mushy audio peak extreme ends from 461.5085 to 461.5185 mhz. That's about 100 khz bandwidth...like WBFM.

Attached are 4 pictures. Pictures 1 & 2 are positive signal polarity. Pictures 3 and 4 are inverted signal polarity all on 461.5135 mhz. which appears to be the center of the signal and provides the strongest input signal. Dsd was selected with "-fr" only to select "MOTOTRBO" signals. Definitely positive polarity appears to be the best such audio such as it is. The audio is not time segmented in "chunks" like it sounds on the inverted signal polarity.

I see both +DMR and -DMR signals depending upon which signal polarity is selected. Using the R7000 attenuator did not significantly reduce the signal input level and I doubt it makes any difference.

 

[W4UVV]

more--uh oh. Now I am hearing short mushy audio on the inverted signal polarity side but not on the positive polarity like previous comms when the same comms were on both polarities. Possibly a two channel operation with one "open" channel and one "private" channel?

 

[W4UVV]

Sounds like a good idea

An easier method would be to right click on Provoice.Bat, select Edit and open it in notepad. You will see the following:

dsd -i /dev/dsp -o /dev/dsp -fp

Change this to:

dsd -xr -mg

and then go file->save as->Mototrbo.bat (make sure in the Save As Type dropdown below the filename you select All Files first before clicking Save)

Now you can just double click the new batch file you created and voila, you should be all set.

I love DSD, it's a great program. I'm still muddling my way though the source code. I would LOVE to make an RD/LAP decoder out of it, but C is greek to me. Still, it'd be fun to be able to pull it off.

Good luck!
-AZ

Tnx for the info. It has been years since I attempted anything in MS DOS. I was very fortunate to remember enough in MS DOS to copy a file and thanks to earlier help get dsd options to display and work. I've spent all day trying different things and so far have learned what doesn't work and am mentally exhausted...ha..ha.
John

 

[ilgrant]

Glad you made some headway today, John!

I don't know if there is a difference in audio sound between an encrypted trbo signal and a clear one. Maybe others can tell you.

You may also need to tweak the input level (mic or line in) to see if you can get improved audio.

By the way...based on your images you are indeed receiving Mototrbo.

 

[W4UVV]

Still trying

Glad you made some headway today, John!

I don't know if there is a difference in audio sound between an encrypted trbo signal and a clear one. Maybe others can tell you.

You may also need to tweak the input level (mic or line in) to see if you can get improved audio.

By the way...based on your images you are indeed receiving Mototrbo.

I have no idea how to improve line in audio. I thought the output level in the R7000 was fixed at the factory setting. No rotation of the audio volume control seems to have any impact on the audio level.

This morning I thought I would try to receive the Madison Co., Va. Sheriff on 154.8000 mhz. who within the past few months converted from analog to MOTOTRBO. The transmitter site is located on Fork Mountain approximately 120 air miles NNW of my location about 30 miles south of Richmond, Va. in Prince George, Co. Attached is a screen capture of the Madison Co. Sheriff's Office MOTOTRBO signal using dsd inverted. No audio was present on the positive signal side. Rats! It is the same mushy segmented audio like I am receiving on an area business MOTOTRBO transmission on 461.5135 mhz.

I'll try mic input. There I am sure the audio volume will impact the output audio. Other than that I do not know what else to try. That's why I need you experts to tell me what I am doing wrong if anything. Since I don't know what should work, I have nothing with which to compare.

I cannot believe that somebody somewhere has not been successful using Windows 7 dsd receiving a MOTOTRBO signal and not posted such on RR somewhere.

MOTOTRBO is here to stay. There are rumors in Va. CSX RR may convert to MOTOTRBO.

Again thanks to all who have tried to help me get educated using DSD.

 

[woodpecker]

I have no idea how to improve line in audio. I thought the output level in the R7000 was fixed at the factory setting. No rotation of the audio volume control seems to have any impact on the audio level.

This morning I thought I would try to receive the Madison Co., Va. Sheriff on 154.8000 mhz. who within the past few months converted from analog to MOTOTRBO. The transmitter site is located on Fork Mountain approximately 120 air miles NNW of my location about 30 miles south of Richmond, Va. in Prince George, Co. Attached is a screen capture of the Madison Co. Sheriff's Office MOTOTRBO signal using dsd inverted. No audio was present on the positive signal side. Rats! It is the same mushy segmented audio like I am receiving on an area business MOTOTRBO transmission on 461.5135 mhz.

I'll try mic input. There I am sure the audio volume will impact the output audio. Other than that I do not know what else to try. That's why I need you experts to tell me what I am doing wrong if anything. Since I don't know what should work, I have nothing with which to compare.

I cannot believe that somebody somewhere has not been successful using Windows 7 dsd receiving a MOTOTRBO signal and not posted such on RR somewhere.

MOTOTRBO is here to stay. There are rumors in Va. CSX RR may convert to MOTOTRBO.

Again thanks to all who have tried to help me get educated using DSD.

Can you record a .wav sample of your discriminator output and post it here or post a link to it?

 

[racingfan360]

Ok John, we are now making some progress.

From your post earlier with 4 sreenshots, I can clearly see that pictures 1 and 2 are decoding correctly as MotoTRBO with the CORRECT polarity. Pictures 3 and 4 are the WRONG polarity. How do i know this...because wrong polarity will sound like a constant machine gun of 'voice' decodes even though the data will be a mix of voice and data. For most MotoTRBO systems, the vast majority of packets sent are signalling data, not voice. For the correct polarity you will see lots of data (like RATE 3/4 DATA, CSBK, UNKNOWN TYPE etc etc) and relatively speaking little VOICE. I know it's confusing to begin with as the minute you get voice coming out of the speakers, you think you've cracked it. It took me several days to work out that I needed to change polariy in some cases. So you need to run as +DMR for this system on this PC. And just to clarify, in my experience the decision to use +ve or -ve polarity depends on the decoding scanner/PC combo, NOT the system you're trying to decode.

The bad news is that if you are running +DMR and you still hear 'parceled up' time segment decodes, you are more than likely decoding encrypted or Privacy enabled MotoTRBO. The way to find out for sure is to run this great java program from Ian Wraith: https://github.com/IanWraith/DMRDecode/downloads. You should be able to run this program at the same time as DSD.

There are lots of details here:
http://forums.radioreference.com/digital-voice-decoding-software/191957-java-program-decode-dmr.html

Note again there is an ability to invert the polarity in DMRDecode so you will need to get this right.
WRONG polarity decodes will show lots of the same message, something like:
<timestamp> DMR Voice FRAME
CACH: TACT Ch1 First Segment of CSBK

CORRECT polarity will show text including stuff like:
Slot Type: Colour Code x Idle
Short LC: Nul_Msg
Group Voice Channel User LC
Service Options: Non-emergency/No Priority
Group Address : x Source Address : x
etc

So when you see/hear VOICE decodes in DSD, what does DMRDecode say:
For group calls that don't have privacy enabled, you'll see something like:
Service Options : Non-emergency/No priority

With privacy it'll look like:
Service Options : Non-emergency/Privacy Enabled/No priority

If DMRDecode is too challenging for you, post a wav file of the raw capture of the TRBO signal and I'll try and unpick it from there.

Jim