700Mhz TDMA and Unitrunker

[SCPD]

Sorry if this is old news -- but last night I finally figured out what Unitrunker was showing me on our X2-TDMA P25 system for King County Metro Transit.

Basically, I was seeing a set of frequencies (700mhz) as LCN 01 but the voice freqs were showing up as 0.0 Mhz and LCN 03. There was no band plan established for LCN 03. I wasn't sure why there was two LCN groups showing up here.

(I don't know how/why but at one point, Unitrunker thought these were in the 150mhz range.)

Eventually, my brain clicked on the fact that TDMA has two slots *per channel* and thus it all made sense. Since each slot is just a frequency step, my theory seemed possible.

The LCN 01 band plan starts at 762.00625 @ 6.25khz steps. I created a duplicate band plan for LCN 03 and everything worked great.

(Math example: LCN 03-1941 = .00625 x 1941 + 762.00625 == 774.1375)

I verified the voice frequencies on a 2nd scanner and confirmed they matched with the active calls from Unitrunker.)

 

[dste]

Here is the summary from Pro96Com. Bandplan 1 is single slot for higher speed data and Bandplan 3 is double slot for voices.

FileVersion:6
-TowerInfo
#This section is here for information only. With the exception
#of the Call Sign(s), This data is not Read back into the program at all.
System ID : 1F9
System Name : King County Metro Transit
WACN : BEE00
Tower Number (Decimal): 101
Tower Number (Hex) : T0101
Tower Description : Seattle 101
Control Capabilities : Data,Voice,Registration
Call Sign(s) : WQHJ934
Timestamp : Wed Dec 7 13:38:17 2011

-Tables
#Format: Table ID,Base Freq,Spacing,Input Offset,Assumed/Confirmed,BandWidth,Slots
00,851.00625,0.00625,-45.00000,"Confirmed",0.00625,1
01,762.00625,0.00625,30.00000,"Confirmed",0.00625,1
02,851.01250,0.01250,-45.00000,"Confirmed",0.01250,2
03,762.00625,0.01250,30.00000,"Confirmed",0.01250,2

-Frequencies
#Format: Channel,Usage,Frequency(/Slot),Input Frequency(/Slot),Hit Count
"01-1202","i",769.51875,799.51875,0
"01-1242","d",769.76875,799.76875,0
"01-1282","d",770.01875,800.01875,0
"01-1322","d",770.26875,800.26875,0
"01-1360","d",770.50625,800.50625,0
"01-1362","d",770.51875,800.51875,0
"01-1940","d",774.13125,804.13125,0
"01-1942","d",774.14375,804.14375,0
"01-1980","a",774.38125,804.38125,0
"01-1982","a",774.39375,804.39375,0
"01-2020","c",774.63125,804.63125,0
"01-2022","ca",774.64375,804.64375,0
"03-1242","v",769.76875/0,799.76875/0,0
"03-1243","v",769.76875/1,799.76875/1,0
"03-1282","v",770.01875/0,800.01875/0,1
"03-1283","v",770.01875/1,800.01875/1,0
"03-1322","v",770.26875/0,800.26875/0,0
"03-1323","v",770.26875/1,800.26875/1,0
"03-1360","v",770.50625/0,800.50625/0,0
"03-1361","v",770.50625/1,800.50625/1,1
"03-1362","v",770.51875/0,800.51875/0,0
"03-1363","v",770.51875/1,800.51875/1,0
"03-1940","v",774.13125/0,804.13125/0,0
"03-1941","v",774.13125/1,804.13125/1,1

-Neighbors
#Format: TowerID,TowerIDHex,System ID,Channel,Frequency,Tower Name
102,"T0102",1f9,"01-1320",770.25625,""

 

[SCPD]

Thanks for the clarification dste. I was half-correct I guess.

I forgot about trying Pro96com. I'll have to check that out with my PSR800.

 

[dste]

How do the TDMA voices sound on the PSR800? I haven't made that addition to my scanner collection yet.

 

[SCPD]

Here's a short recording:

PSR-800 monitoring X2-TDMA P25 system - YouTube

It really just depends on signal quality. At times, it can get pretty bad and I can't understand a thing anyone is saying. At other times, it sounds pretty good.

 

[SCPD]

dste, I got psr96com up and running tonight. Very interesting software. Took me a while to figure it out with the PSR-800 but finally managed to get it working.

 

[dste]

It has it's uses. I wonder why you did not get the 3rd bandplan from Unitrunker?

 

[SCPD]

Not sure. I can only think it's because I was using discriminator audio versus the CC dump from the PSR-800. (I didn't use the CCDump until I loaded up psr96com.)

I'll try it with my 396XT on Unitrunker tonight and see if it picks up the other band plan.

 

[SCPD]

The X2 TDMA messages are slightly different from the standard TDMA messages. I don't have any TDMA (X2 or standard) in my area so this isn't well tested.

 

[SCPD]

Thanks for the info Rick. If you need any logging from me (or if I can help) let me know.

dste, I tried the 396xt with psr96com and it worked just like the psr-800 in getting the third band plan.

I don't know why, but I cannot get my 396xt to work with the inline option in Unitrunker v24. I have the CC dump set to "ON" and not extended.

I know the physical set up is working because I can close Unitrunker and open psr96com and that works fine.

 

[jje64]

I am attempting to use unitrunker with the Bucks County PA 700 Mhz system. I appear to have good signal strength on the radio. I only have a max health of 32 in unitrunker. The software recognized the system and displays the control carrier freq. But it does not decode anything from the system.

The radio in use is an Icom R7000 so I can't go to better than 100 Hz on freq.

The sound card is running at 96kbs at 16 bits.

Is there something else I am missing?

I just aligned the radio with my service monitor and I know it is within 50 Hz of displayed freq.

Thanks
Jje64

 

[SCPD]

Your settings of 96000 sps at 16 bits per sample sound good.

Please post some UniScope images of the control channel waveform. Some images to try ...

1. Oscilloscope
2. Impulse at 4800 baud

 

[jje64]

The Uniscope that loaded with the Unitrunker load (version 1.0.0.24) does not appear to show any data. I tried this on both the system in question and on a good/known to work P16/SmartZone system.

THe Uniscope version says V1.0.0. It looks nothing like the window shown in some searches on RR. Is there a newer version of Uniscope? Where might I get it? I tried the Unitrunker website and see not download for Uniscope.

Sorry for the lack of data. Any help on where I could get a working version of Uniscope is appreciated

Thanks
jje64

 

[SCPD]

How about a picture of the Scope tab on your Receive window?

 

[jje64]

THis is what the scope within Unitrunker shows

 

[SCPD]

Make sure your computer's audio options (like auto gain and noise cancel) are turned off.

What's the bandwidth on the R7000?

 

[jje64]

The soundcard in use is an external USB sound card. It and any software on the PC have no noise cancel functions, etc. The gain on the soundcard is set via a front panel pot. I have it adjusted to be below the clipping point. Though I did very the gain on the pot and all that occurs is a change in amplitude on the o'scope.

By BW I assume you are asking about the filter setting on the R7000. The mode/filter selected is NFM (15 kHz). The R7000 also has a super narrow setting of 6 kHz. I considered that, but that is smaller than the occupied BW of the control carrier. I did try it though, and it did not improve the situation.

I also varied the tuned frequency of the R7000 in 100 Hz steps to see if the health improved. No help, the max health I can achieve is 32.

Any other suggestions?

 

[SCPD]

Does the R7000 include a built-in discriminator audio connection?

Edit: it doesn't. What tap did you use?

 

[jje64]

I am using the discriminator tap that I added to the radio. I don't have the tap point handy, but it is generally available on the internet.

This same tap has worked fine for an 800 MHz P25 system and for the a 500 and 800 MHz Smartzone system. I would expect the control carrier format and symbol rate to be the for the 800 MHz and 700 MHz P25 systems. Though, maybe I am mistaken.

 

[SCPD]

I would expect the control carrier format and symbol rate to be the for the 800 MHz and 700 MHz P25 systems.

There are only two formats - C4FM and CQPSK. The waveform looks rough but it isn't CQPSK.