TRX-2: P-25 Phase II simulcast

[TexScan780D]

Is there any setting in the TRX-2 scanner or the programing software to tweak the improvement of the conversations on a P-25 Phase II simulcast system?

 

[buddrousa]

none

 

[Colin9690]

Is there any setting in the TRX-2 scanner or the programing software to tweak the improvement of the conversations on a P-25 Phase II simulcast system?

Yes, there are. However, there isn't any guidance in the manual on how to use them, or an instant recipe for a solution. The lack of information from Whistler might be what they intended, since every trunking system is different.

There are 3 programming parameters you can tweak. See this page: GRE/RS/Whistler based DSP ADC/DAC Adjustments - The RadioReference Wiki

Like I said, every person's setup is going to be different, but for the simulcast system my county uses I use ADC -2, DAC -7, DSP 80. This combo makes reception noticeably better for me. Not perfect by any stretch, but better than with the factory defaults.

Two tips about changing these values...for the DSP, change it in small increments (maybe by multiples of 10). Lastly, change one setting at a time only. Just like in any experiment, you can't figure out what's causing the change when you're manipulating more than one variable at once. This is where the trial and error comes into play.

Beyond this, looking into a good antenna setup is the next step to improving simulcast reception.

Hope this helps, and have fun.

 

[Ubbe]

ADC are the audio level in to the DSP chip. DAC is the output level from the DSP and have nothing to do with the decode process of digital signals and are only there to balance the audio level between analog and digital conversations.

/Ubbe

 

[TexScan780D]

Yes, there are. However, there isn't any guidance in the manual on how to use them, or an instant recipe for a solution. The lack of information from Whistler might be what they intended, since every trunking system is different.

There are 3 programming parameters you can tweak. See this page: GRE/RS/Whistler based DSP ADC/DAC Adjustments - The RadioReference Wiki

Like I said, every person's setup is going to be different, but for the simulcast system my county uses I use ADC -2, DAC -7, DSP 80. This combo makes reception noticeably better for me. Not perfect by any stretch, but better than with the factory defaults.

Two tips about changing these values...for the DSP, change it in small increments (maybe by multiples of 10). Lastly, change one setting at a time only. Just like in any experiment, you can't figure out what's causing the change when you're manipulating more than one variable at once. This is where the trial and error comes into play.

Beyond this, looking into a good antenna setup is the next step to improving simulcast reception.

Hope this helps, and have fun.

I read some of the article on RadioReference Wiki, maybe I missed it in the article or the scanner, but do I have to do the settings in the programing software or the scanner? thanks!

 

[TexScan780D]

ADC are the audio level in to the DSP chip. DAC is the output level from the DSP and have nothing to do with the decode process of digital signals and are only there to balance the audio level between analog and digital conversations.

/Ubbe

Okay thank you. Sometime the conversations are okay, then to low or to high pitch. Kind of hard figuring if changing the ADC or the DAC setting.

 

[troymail]

All of the undocumented settings are probably optimized as much as they can be. There's not alot of reasonable things you can do with digital simulcast issues beyond experimenting with these settings but you shouldn't expect too much.

Every user's situation will be different given their location as it relates to the transmitting simulcast towers of each system you try to monitor. Over the years, I've found that position of the radio - a couple of inches this way or that way make all the difference. However, factors that are far too complex to understand result in that location only working for a time before an adjustment in location is required again.

I moved away from most simulcast systems in the last year and now have the opposite problem - primarily, a weak non-simulcast statewide system. However, on a recent trip back to "simulcast hell", I found myself once again fighting with placement of my radios (Whistler and Uniden) to receive area simulcast systems... and, after a brief period, just opted not to contend with that aggravation again. Thankfully, the local trunking system where I was hasn't yet upgraded to P25 and is still half analog.

 

[Ubbe]

Sometime the conversations are okay, then too low or too high pitch. Kind of hard figuring if changing the ADC or the DAC setting.

Those are caused by bit errors in the data stream. So only ADC and DSP settings have any influence on it.
I think Whistler screw it up with the available settings for ADC and DAC levels. It's a huge difference in DAC settings +2 to -10 and there's no need for them as digital and analog sounds almost at the same volume anyhow. But ADC settings are a lot more important for finetuning but are restricted to +2 to -2 which are too little to be of any use. When the TRX scanners where introduced they had their levels messed up so that when you programmed a value it came back different and unchanged when your read the scanner. I believe they are still messed up and not working properly even today.

/Ubbe

 

[TexScan780D]

All of the undocumented settings are probably optimized as much as they can be. There's not alot of reasonable things you can do with digital simulcast issues beyond experimenting with these settings but you shouldn't expect too much.

Every user's situation will be different given their location as it relates to the transmitting simulcast towers of each system you try to monitor. Over the years, I've found that position of the radio - a couple of inches this way or that way make all the difference. However, factors that are far too complex to understand result in that location only working for a time before an adjustment in location is required again.

I moved away from most simulcast systems in the last year and now have the opposite problem - primarily, a weak non-simulcast statewide system. However, on a recent trip back to "simulcast hell", I found myself once again fighting with placement of my radios (Whistler and Uniden) to receive area simulcast systems... and, after a brief period, just opted not to contend with that aggravation again. Thankfully, the local trunking system where I was hasn't yet upgraded to P25 and is still half analog.

Simulcast is a pain. I'll try moving the scanner around and fiddly with those adjustments.

 

[Nasby]

Simulcast is a pain. I'll try moving the scanner around and fiddly with those adjustments.

Also, try a paper clip in the antenna slot.

 

[milcom_chaser]

We went through all of that, and later purchased a Uniden 325P2 which worked fine on our simulcast system.
The whistler radio has been relegated to DMR and recording audio...

 

[Colin9690]

I read some of the article on RadioReference Wiki, maybe I missed it in the article or the scanner, but do I have to do the settings in the programing software or the scanner? thanks!

You can do it from the radio’s keypad, or through the software. Either way will work.

 

[TexScan780D]

Also, try a paper clip in the antenna slot.

Never tried a paper clip. You just slide the clip into the center hole?

I appreciate all the tips and keep them coming. Happy New Year everyone.

 

[Nasby]

Never tried a paper clip. You just slide the clip into the center hole?

I appreciate all the tips and keep them coming. Happy New Year everyone.

Yep. Bend it upward though before inserting it in the hole.

It stinks that we have to try these crazy fixes but unfortunately that's what we're faced with when it comes to trying to receive simulcast systems by these "modern scanners" from the two scanner companies.

 

[TexScan780D]

I think that I have never seen.

ZM Delay
ZM Threshold
ZM Slope

Any ideas on what these settings are?

 

[TexScan780D]

Yep. Bend it upward though before inserting it in the hole.

It stinks that we have to try these crazy fixes but unfortunately that's what we're faced with when it comes to trying to receive simulcast systems by these "modern scanners" from the two scanner companies.

Do I unfold the entire clip?

 

[Nasby]

Do I unfold the entire clip?

Try it with different lengths. But don't bend it while it's in the hole.

I ended up cutting about half off to get somewhat decent reception.

 

[TexScan780D]

Try it with different lengths. But don't bend it while it's in the hole.

I ended up cutting about half off to get somewhat decent reception.

Okay thank you.

 

[TexScan780D]

I use ADC -2, DAC -7, DSP 80.

I set the scanner to your setting and the dispatch sounds good majority of the time, but some of the mobiles sound okay but some sound a little high pitch and sound muffle.

 

[AC9BX]

Attenuation can be your friend (or enemy). Less signal can reduce interference from other sites to the strongest one your radio hears making it easier to decode. (or not) It's trial and error. The radio struggles with trying to demodulate a signal in the presence of another, or more. Eliminating the others is the best that can be done with these radios as they are but that isn't always easy.