Getting MTrunker32 working on a UHF system

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Joseph11

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I've recently downloaded T4Win and it works great, but it crashes alot. I downloaded MTrunker32 made by r00t and it's decoding the control channel, but insted of it giving me frequencies in the console, it's giving me hex values. I am trying to use MTrunker32 with the Ocean County, NJ TRS. I don't know where or how to enter in the custom frequency table, if it requires it. I have attached the config files and a screen shot from MTrunker32. Thanks.

EDIT: I ran MTrunker32 for a few hours, it collected some more information.
 

SCPD

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Search this forum for information on how to create a map file. With that, the program is able to fill in the frequencies.

-rick
 

Joseph11

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rfmobile said:

I still don't understand, but I manually added in the frequencies. There's two I don't know.

Code:
Ocean County
MAP=22222222
OPTIONS=nvDf
PLAN=0
DESCR=Type II 116.3 Hz
THRESHOLD=50
DISPOSITION=fvlxsr
c v506.6125,1fd,81,31cb
  v506.6625,201,85,3434
  v0x20d   ,20d,ffff,58
  v508.0625,271,f5,357a
  v508.0875,273,f7,7c42
  v508.1375,277,fb,31c2
 d 0x28f   ,28f,ffff,0
 

SCPD

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Based on these numbers, looks like the system has a base of 500.25 mhz with 12.5 khz channel spacing.

Plugging the numbers in gives these channels.

506612500
506662500
506862500
508062500
508087500
508137500
508437500
 

Joseph11

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rfmobile said:
Based on these numbers, looks like the system has a base of 500.25 mhz with 12.5 khz channel spacing.

Plugging the numbers in gives these channels.

506612500
506662500
506862500
508062500
508087500
508137500
508437500

Thanks, the RadioReference DB says that it has a base frequency of 505.0000 MHz, but I think that may be wrong now.
 

DaveH

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rfmobile said:
Based on these numbers, looks like the system has a base of 500.25 mhz with 12.5 khz channel spacing.

Whatever happened to offset >= 380 (0x17c)? Wouldn't this system use 506-512MHz; 506-509 with +3MHz TX-RX? In that case the base isn't likely below 506MHz.

Working backwards, the base could be 505.000MHz with offset 380, but I doubt it, since that's in a different 6MHz block; more likely 506.0125MHz, offset 461, or 506.000 offset 460. That would not be Range 1 of the system.

Dave
 

SCPD

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DaveH said:
Whatever happened to offset >= 380 (0x17c)? Wouldn't this system use 506-512MHz; 506-509 with +3MHz TX-RX? In that case the base isn't likely below 506MHz.

I'm using the formula ...

Code:
frequency = base-freq + (channel #) times spacing

... as opposed to ...

Code:
frequency = base-freq + (channel # - offset #) times spacing

In other words, I'm using an offset of zero. I realize this isn't the convention followed in the RR DB but it's algebraically simpler and one less number to worry about. On a system with multiple table entries then - yes - you want the offset to distinguish different blocks of channel numbers.

Getting back to Joseph's question ... here is an example map file posted by Lou Maag in a previous message on this forum.

File Name: 880aMAP.txt
155.4150,0.015,17c
157.2000,0.0125,1b4
157.4700,0.015,1c6

"880A" is the Motorola system id for the system he was monitoring. You will have to name your file prefixed with the appropriate four digits for your system. Try creating the file with a single line, like so ...

500.25,0.0125,0

That should do the trick. If you want to use the standard offset of 380, try this instead ...

505.0,0.0125,17C

-rick
 

Joseph11

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I restored the old 5c3fSys.txt and 5c3fSys.bak with the hex values and created a file called 5c3fMap.txt and put a single line it it, "505.0,0.0125,17C", without the quotes. I started up Trunker and it's still showing the hex values, any idea on why it's not working right?
 

Joseph11

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It already is.

EDIT: I erased all the frequency information it had and now it works. Now, I have another question. Can I give alpha tags to the talkgroups or make it display them is decimal mode?
 

DaveH

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rfmobile said:
I'm using the formula ...

Code:
frequency = base-freq + (channel #) times spacing

... as opposed to ...

Code:
frequency = base-freq + (channel # - offset #) times spacing

In other words, I'm using an offset of zero. I realize this isn't the convention followed in the RR DB but it's algebraically simpler and one less number to worry about. On a system with multiple table entries then - yes - you want the offset to distinguish different blocks of channel numbers.


-rick


I used to extend the offset down to zero, but in the end if it is used to program a scanner, it has to be adjusted back anyway, so why not do it up front. Offset 0 applied to system outputs is technically incorrect because the system inputs use channel numbers 0-379 (0x000 to 0x17b). I don't think most scanners will accept or function properly with offset less than 380 anyways.

All VHF/UHF systems have three ranges and the more I look at this one, suspect that the channel numbers used are probably Range 2. Base 505.0000MHz falls into a range of inputs 503-506, for the block 500-506. It is possible no Range 1 frequencies are in use now, and may never be used; in that case, one can't figure out what the base/offset for Range 1 would be. Something would still need to be programmed into the scanner.

This is what I'd try: set up two ranges as follows:

Range 1: Base 505.0000, Offset 380, Step 0.0125
Range 2: Base 506.0000, Offset 460, Step 0.0125

In the MAP file it would be

505.0000,0.0125,17c
506.0000,0.1025,1cc

These two ranges are contiguous. If any Range 1 channels i.e. between 380 and 459 come into use, the "real" Base 1 frequency can be figured out.


Dave
 

Joseph11

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OK, thanks. I changed the map file and found out how to add alpha tags. Someting odd though, it reported 506.8125 MHz as 506.8625 MHz. I manually changed it.
 

loumaag

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Joseph11 said:
OK, thanks. I changed the map file and found out how to add alpha tags. Someting odd though, it reported 506.8125 MHz as 506.8625 MHz. I manually changed it.
I am not sure but you may have not realized that there is a typo in the MAP file info given above.
Code:
505.0000,0.0125,17c 
506.0000,0.1025,1cc
probably should read:
Code:
505.0000,0.0125,17c 
506.0000,0.0125,1cc
 

Joseph11

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loumaag said:
I am not sure but you may have not realized that there is a typo in the MAP file info given above.
Code:
505.0000,0.0125,17c 
506.0000,0.1025,1cc
probably should read:
Code:
505.0000,0.0125,17c 
506.0000,0.0125,1cc

Yeah, I realized it. Thanks for pointing it out though.

EDIT: I have now attached a screenshot of everything working correctly.
 
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