TRX-2: Issues With DMR Trunked System

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mfn002

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I just received a TRX-2 yesterday. I attempted to monitor a local Tier III 800MHz DMR system but I'm missing most of the traffic on the system. It seems to track other DMR systems just fine. Am I missing something?


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mfn002

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I'm beginning to wonder if the scanner isn't "seeing" all of the frequencies in the system.
 

Ubbe

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I agree that some frequencies might be missing or isn't received properly.

I suggest you get a 3.5mm audio cable and connect from IF out to a PC that is running the free DSD+ program. Set the TRX-2 on the a control channel and let DSD+ decode and show the voice channels its sending the mobiles to. Then analyze the result and enter all voice frequencies in the TRX-2.

The IF out on the TRX-2 have an excellent quality for decoding purposes.

/Ubbe
 

mfn002

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I agree that some frequencies might be missing or isn't received properly.

I suggest you get a 3.5mm audio cable and connect from IF out to a PC that is running the free DSD+ program. Set the TRX-2 on the a control channel and let DSD+ decode and show the voice channels its sending the mobiles to. Then analyze the result and enter all voice frequencies in the TRX-2.

The IF out on the TRX-2 have an excellent quality for decoding purposes.

/Ubbe


I do have all of the frequencies for the system programmed in, and my two 536HPs track the system okay. I'll get traffic from the system on my 536s, but the TRX will just continue to scan. I have checked and double checked the frequency list, and everything is correct.


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mfn002

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I also noticed another problem with this scanner:

It appears to have difficulty connecting to my computer. I'm almost constantly getting some sort of error message when I try to read/write. It tends to give me one of the following error messages:
1. The SD card isn't formatted correctly.
2. Disconnect and reconnect the USB cable.
3. Remove and re-insert the SD card.

Normally, it takes about 2 or 3 tries before I can get the scanner to respond.
 

Ubbe

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The USB connection between my win7 and TRX-2 is terrible, often get no connection messages. Never a problem with other scanners or devices.

Use the siren app to see the site and frequency that the 536 uses when you do not get anything on the TRX and check that you have that frequency programmed correctly. You could also quick enter (fn+0) that frequency and check if you hear it and it should also decode it in au mode.

/Ubbe
 

BrianG61UK

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The USB connection between my win7 and TRX-2 is terrible, often get no connection messages. Never a problem with other scanners or devices.
Yes, the scanner is particularly fussy about the type of USB port it is connected to (and/or it's drivers).

I fixed the USB connection problems with my WS1088 and my Desktop PC (running 64 bit Windows 7) by installing an older PCIe card with older type USB2 ports on it which use the older OpenHCI drivers for USB1.

The card I used was an ST-Lab U-650.

I did not use the driver CD that came with the card, I just let Windows 7 install drivers from Windows Update.
 

mfn002

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First of all, I am using a later version of Windows, not 7. Second of all, I am using a laptop, so changing out the USB ports isn't really an option.

Anyway, let's get back to the original topic. I am still scratching my head over why the scanner is skipping over the system so much. I'd say it is only receiving about 5-10% of all of the traffic on the system, and it will often skip over the system multiple times even when my other scanners are picking up an active channel.
 

CycleSycho

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First of all, I am using a later version of Windows, not 7. Second of all, I am using a laptop, so changing out the USB ports isn't really an option.

Anyway, let's get back to the original topic. I am still scratching my head over why the scanner is skipping over the system so much. I'd say it is only receiving about 5-10% of all of the traffic on the system, and it will often skip over the system multiple times even when my other scanners are picking up an active channel.
:mad: Technology, one step forward three back... Guess 'right out of the box' isn't the same for different people? Isn't 'new' supposed to be easier? :mad:
 

Ubbe

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We all know that win10 are problematic with unsigned driver and such but just wanted everyone to know that TRX are also problematic with win7, so probably a genuine TRX issue with USB handling.

If you followed my advice, did you hear anything on the TRX when manually monitoring the frequency that the 536 says is the active voice channel? If you leave the squelch open on that frequency, do you hear clean white noise or maybe interferencies and bleed through from other frequencies?

When you do hear traffic, is it continuosly during the time the call is on that frequency or do it drop out?

/Ubbe
 

mfn002

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Try lowering your squelch to 8 and increase the dwell time on the system default is .3 seconds.
I already have the squelch set to 8. The default dwell time on mine shows 1.0 seconds. What do you recommend I increase it to?
 
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Ubbe

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The 8 squelch will probably receive signals too noisy to be decoded and will hesitate on that CC too long until it will continue to scan.

First check that you can successfully decode the signal while entering the voice channel manually to monitor it stationary. If that works you can then adjust parameters for scanning.

The dwell time depend on how many control channels you have in the system. I would recommend 0.3 sec per CC that you can hear at one time. If you hear 3 CC then use 1 sec, if you hear 6 CC then use 2 sec.

If the system doesn't use, or rarely use, the slot 2 on the CC I recommend that you remove the CC frequencies. TRX uses dwell time per system, not per site as 536, so it depends on how many simultaneous carriers with DMR signalling you scan and how many TGs you lock out. If you monitor all TGs then the default 1 sec will be more than sufficient. If you lock out a lot of TGs and only monitor a couple, then you need to calculate how many simultaneous active voice channels you can receive and multiply with 0.3 sec and if the system often gets fully loaded with voice traffic then you also need to have the CC channels in scan and must also consider 0.3 sec per CC.

For testing purposes you can easily try a 5 sec dwell time just to be sure that you do not have a dwell problem. But as I have mentioned, check that you can monitor the voice channel manually that the 536 uses when you do not get anything when the TRX are scanning.

/Ubbe
 

seth21w

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The 8 squelch will probably receive signals too noisy to be decoded and will hesitate on that CC too long until it will continue to scan.

First check that you can successfully decode the signal while entering the voice channel manually to monitor it stationary. If that works you can then adjust parameters for scanning.

The dwell time depend on how many control channels you have in the system. I would recommend 0.3 sec per CC that you can hear at one time. If you hear 3 CC then use 1 sec, if you hear 6 CC then use 2 sec.

If the system doesn't use, or rarely use, the slot 2 on the CC I recommend that you remove the CC frequencies. TRX uses dwell time per system, not per site as 536, so it depends on how many simultaneous carriers with DMR signalling you scan and how many TGs you lock out. If you monitor all TGs then the default 1 sec will be more than sufficient. If you lock out a lot of TGs and only monitor a couple, then you need to calculate how many simultaneous active voice channels you can receive and multiply with 0.3 sec and if the system often gets fully loaded with voice traffic then you also need to have the CC channels in scan and must also consider 0.3 sec per CC.

For testing purposes you can easily try a 5 sec dwell time just to be sure that you do not have a dwell problem. But as I have mentioned, check that you can monitor the voice channel manually that the 536 uses when you do not get anything when the TRX are scanning.

/Ubbe
Squelch of 8 is not low enough to cause that but as long as every frequency has at least a ctcss it shouldn't have any static no matter the squelch number. But I scan analog digital dmr and cap+ dmr channels together and 8 is just right for all systems. 10 will miss a lot of transmissions, I have 536 and 1098 sitting together and same antenna for both and the 1098 scans quicker and picks up slightly quicker than my 536 on 8 squelch.
 
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