DSP Settings

N1NIJ

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Mar 14, 2018
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I’m wondering if the DSPLevelAdjust settings might help with P25 simulcast issues. Sometimes I get some garble, sometimes clipping or missed parts of the transmission - even with several signal bars. Also, time of day seems to have an impact for some reason. Usually I just physically put the TRX-1 somewhere else and that usually works but I wonder if the dspleveladjust is designed to help with this issue.
 

Daleb49

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I have changed it on all 3 of mine and sometimes it does help a little.
Most of mine are at 64 and has been recommended on her to make changes in steps of 7.
There are many theories on this and I also switch my antenna to a short stubby one.
I live in a city that is a simulcast system and all my Whistlers have no trouble with it which I'm surprised about.
I have trouble sometimes with greater Cleveland system and also Ohio Marcs.
I like you have found location is key to getting good reception and also weather conditions have an effect.
Most posters on here will say Whistlers don't work at all on simulcast systems and they clam the way Whistler does DMR and NXDN that doesn't work either. I'm happy with the reception I get including Jack Casino with 18 trunk groups (not all listed in RR) and over 200 radios.
If you have a little patience and don't mind a little trial and error you can have some good reception.
 

N1NIJ

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Part of me hopes that something new is coming along that will deal with these things, however, reading other threads here aren’t too good for having a sense of optimism…who knows.
 

CycleSycho

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Part of me hopes that something new is coming along that will deal with these things, however, reading other threads here aren’t too good for having a sense of optimism…who knows.


:( Been asked for and hoped for but I doubt it'll be forthcoming. Only thing that might do it would be a new series of radios from Whistler (personally, doubt it). :(


.
 

N1NIJ

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:( Been asked for and hoped for but I doubt it'll be forthcoming. Only thing that might do it would be a new series of radios from Whistler (personally, doubt it). :(


.
Well, being fairly new to the scanner hobby, I don’t have a good sense to be able to gauge how often the scanner companies release new stuff. That being said, forever is a long time. 😳
 

N1NIJ

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Here is a guide that helped me get mine running. P25 sounds good on it now.
This is most likely my issue. I have looked at that page more than once, and it for me it makes for more questions than answers!
ADC: are P25 signals received somehow as analog and need conversion-and why 0 or a negative number and not positive?
DAC: some posts say this is to balance out how loud the audio sounds compared to analog (I’d like to have that explained with different words) , and again, setting it to 0 or negative - again I‘m not understanding that.
The above charts talk about “too much/too little “ “no signal” ??
Looking at my own post, I am trying not to come across sounding too moronic!
Any & all help is appreciated!
 

Ubbe

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ADC: are P25 signals received somehow as analog and need conversion-and why 0 or a negative number and not positive?
Yes, radiosignals are always analog and you have to convert the received signal to digital to be able to process them in a digital microprocessor. To be able to hear the audio you will need to convert the digital result to analog audio.

Link to DSP Level Adapt

/Ubbe
 

N1NIJ

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Yes, radiosignals are always analog and you have to convert the received signal to digital to be able to process them in a digital microprocessor. To be able to hear the audio you will need to convert the digital result to analog audio.

Link to DSP Level Adapt

/Ubbe
Thanks, Ubbe! I re-read your older post and learned more - sometimes it is better to go over things more than once.
One thing that does get me stuck is that in some posts users say that they got better results changing the dsp level higher or lower than 64 - and usually tell you what number they use, but don’t illustrate exactly WHAT improved - what quality actually changed. Can you or others who may be reading this add some input here? Thanks!
Rick
 

Ubbe

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Can you or others who may be reading this add some input here? Thanks!
The only thing that can change are the audio quality. The more errors you get in the digital data the more the voice will be distorted. The ADC and DSP settings can be tested with different values to see which ones that will improve the audio quality and then change the value even more until it goes worse and then go back to where the quality where the best.

I would start with DSP at default 64 and change ADC to the best possible quality and after that go to DSP and try and find the best setting. But values are global and the same for all systems so use the most important system for the adjustments, if that system are bad. If it's a simulcast system then it will probably change what are the best settings over time and will be impossible to do correctly.

/Ubbe
 

N1NIJ

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Thanks Ubbe, and I agree with your comments. So far, my own experience has been that the ACD seems to matter first - I tend to move back and forth from 0+ to -1 (have not tried any + values as people seem to say not to do that) and then to play with the DSP values. For me, I tend to settle back to the DSP 64 setting as higher or lower values change over time (as you mentioned in your last post). I did change the high/low threshold settings to 85/45 - still trying to figure out if this makes any difference.
 

Ubbe

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I tend to move back and forth from 0+ to -1
First use bigger steps to see that the change actually have an impact on the audio quality, and be not afraid to use + values, try them all. If you do not notice any changes then there's probably no point in trying to fine tune in small steps.

When you change volume level or squelch it's done live while you are listening, and TV sets shows the picture while you change contrast or brightness. Whistler should have those ADC/DAC/DSP values be adjustable while listening. How would you otherwise know in what direction you should go with the adjustments and if they actually do something when changed.

/Ubbe
 

Jphila20

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I have changed it on all 3 of mine and sometimes it does help a little.
Most of mine are at 64 and has been recommended on her to make changes in steps of 7.
There are many theories on this and I also switch my antenna to a short stubby one.
I live in a city that is a simulcast system and all my Whistlers have no trouble with it which I'm surprised about.
I have trouble sometimes with greater Cleveland system and also Ohio Marcs.
I like you have found location is key to getting good reception and also weather conditions have an effect.
Most posters on here will say Whistlers don't work at all on simulcast systems and they clam the way Whistler does DMR and NXDN that doesn't work either. I'm happy with the reception I get including Jack Casino with 18 trunk groups (not all listed in RR) and over 200 radios.
If you have a little patience and don't mind a little trial and error you can have some good reception.
The way Whistler does DMR and NXDN that doesn't work either. I have the TRX-2 and us it primarily in my car. NXDN in Conneaut worked fine. Not a lot of those system west of Cuyahoga. Finding the sweet spot for ADC/DAC/DSP when on the road is like finding a Unicorn. They are right that an adjustment to those setting while listen would solve the issue. At home I use Unitrunker and it works great.
 

Ubbe

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The way Whistler does DMR and NXDN that doesn't work either.
The settings only have an impact on P25 signaling. I'm not even sure that the level setting in DAC actually did something to DMR/NXDN. The DMR activity here during covid are almost non existing.

/Ubbe
 

Jphila20

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The settings only have an impact on P25 signaling. I'm not even sure that the level setting in DAC actually did something to DMR/NXDN. The DMR activity here during covid are almost non existing.

/Ubbe
I don't know of too many cities using DMR/NXDN other than Conneaut in Northern Ohio. I've had my TRX-2 for about 5 years and have yet to find a setting that works well all the time.

Happy Thanksgiving
 

Ubbe

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The DAC setting, the audio level of decoded digital signals, did actually work with DMR when I tested now. The audio AGC function in TRX are so efficient that it compensates for almost all the changes of DAC but when I disable all AGC and change between -10dB to +2dB, a 12dB change in the voltage, I hear that as a doubling of the volume level, and most people will says that 10dBA equals to a doubling of the volume level. So the setting probably works as it should for all digital signals.

I have earlier done ADC testing, the level into the DSP digital decoder, using a barely decoded DMR signal with bit errors and could not see any difference between -2dB 0dB and +2dB. I earlier also tested the DSP Level Adapt setting with DMR and it did nothing for weak signal DMR decode quality.

/Ubbe
 
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