TRX-2 P25 advanced settings

[skip0157]

I'm new to the TRX-2, but I have had a PSR500 for years. I live in MA near the RI line and am trying to listen to the RISCAN North system. I have it programmed as a single site and usually have 4-5 bars of reception. However, many of the transmission are either missed to cut off.

Does anyone have a suggestion for advanced settings in the EZ Scan software? I'm using the stock antenna and other analog trunked systems and conventional p25 channels seem to be fine.

Currently the DSP Level Adapt is 64, ADC gain is +0, and DAC gain is +4. I have done a search but don't really see anything definitive posted.

Thanks.

 

[sparklehorse]

Is this a simulcast P25 system? If so, there is no consumer scanner yet that always handles this type of system well. For my local P25 system I have tried adjusting the DAC, ADC, and DSP level adapt settings on my TRX-2, but have seen no real improvement vs. the default settings. Generally speaking, the most helpful thing you can do is to first try attenuation, then from there experiment with antennas. Sometimes just moving the radio, or using a paper clip for an antenna works, but I think most folks, including me, have seen the greatest improvement by using a yagi type antenna appropriate for the frequency band. Usually this would be aimed at the closest tower in your simulcast system, but you should try aiming in other directions as well to see what works best for you. Yagis in the 700-800 MHz range usually aren't very large or expensive, so this is a pretty reasonable solution for a hobbyist to try.
.

 

[Anderegg]

What do the DAC and ADC settings adjust?

Paul

 

[trentbob]

I agree that there is no scanner that can handle these 700 megahertz simulcast systems. In my part of the country the Uniden scanners do work better but still have a problem in portable and Mobile use and the audio is not always good. GRE or Whistler scanners do not work at all as you move around in between Towers. I use a Motorola subscriber radio for these systems. I bought the TRX 1 for the NXND and that doesn't work properly either. Constant missed or broken transmissions. They say they will find a fix and we are waiting. We have been waiting for over a year for a fix for the simulcast and it hasn't come but the company still claims it's capable of picking them up. At what point does it become Consumer Fraud? If they can not pick up the systems because of LSM that's fine but stop claiming that they do. That's false advertising. It's a consumer protection issue. People are spending a lot of money for radios that don't work as advertised. There is a core group of fans that defend the radios and the company even if they don't get the results they paid for. That's fine too as it's all part of your hobby. There's also a lot of people who are disappointed that the radios don't work as advertised. As more P2 simulcast systems come online the problem will become more pronounced. If the radio works good for you ln your area on P2 simulcast using all the well-known methods then good for you. You are very lucky... enjoy it. For those of you getting ready to spend their hard-earned money and expect to pick up P2 simulcast... Buyer beware.

 

[JD21960]

The other's have it nailed. The settings won't do anything for "receptions" only DSP level adapt can have bearing as it how FAST the scanner adapts to P25 changes in the system. I have mine at 254. I want it to react FAST, never slow. A 700/800mhz Yagi and the Radio Shack 800mhz antenna for traveling are probably the only things that can help these scanners on P25 Simulcast. I can't agree that the company is fraudulent in any way as I can get the same Simulcast system in perfectly in a basement 20 minutes west of here compared to choppy garbage here at home with the stock antenna or any ducky antenna. In fact where three SITES of different counties for our State-wide Starcom21 system overlap to my West... I get them all in great, even Phase 2 Simulcast. I have video of it. It's all location, location, location and the number of antennas flooding the area. Out west there's less antennas sending simulcast signals. These scanners from Whistler do get the systems they claim, it's just that many of us aren't in a perfect spot compared to others. I've seen people with videos on Youtube confused why there's even any fuss or complaint..."See, I get it perfect!" The only fixes are better antennas, location and or getting a Unication G4/5 or big$$$ digital radio like Relm, Motorola or Harris. I am kind of surprised that these scanners don't even receive as well as 2004 radios like my Pro96. That thing never loses the Control Channel on the same P25 Simulcast system. It's a reception champ, Made in 2004? or 2005? I figured these new units would blow it away. Not so, so it's adapt,complain or quit the hobby.
To answer that last question:
• DSPLevelAdapt – Controls how fast the DSP
adjusts to varying P25 levels (default: 64). Higher
values = faster rates.
• ADC Gain – Controls input signal to CODEC
(default: +0dB).
• DAC Gain – Sets output signal from CODEC,
varying the audio level of decoded digital signals
(default: +0dB).

 

[Anderegg]

I don't ever remember seeing a scanner advertising that it specifically picks up "linear simulcast systems".

This would be like complaining your in car HDTV is not picking up VHF channel 2, even though it is advertises as capable of receiving that frequency.

The performance shortcomings are 100% due to the scanner manufactures not putting more money into the design and parts. I don't think you can DSP fix any of the current crop of scanners, as their receiver components simply cannot grab the bits out of the air when LSM is involved...cannot decode what you cannot account for bitwise.

Paul

 

[trentbob]

Although I am very familiar with everything we are talking about and participated in the first video P2 shootout on YouTube over a year ago there are a lot of people that just want to pick up the police in their area. Scanner companies don't say they can pick up LSM they just claim the radio works on the systems. I guess we need more disclaimers for the people who don't know it probably won't work for them for whatever reason. My apx 7000 works great In LSM obviously. The location I live or work I have never had one of these scanners work using all the methods we discussed. There have been a few stories of people who if they turn off the squelch making the radio useless for anything else and hop on one foot in the corner of the basement wearing a tinfoil hat can get it to work LOL. I just don't think it's honest to claim it works on those systems subject to LSM without some kind of disclaimer giving the consumer a clue it may not work for them. To the OP... there's quite a bit of information on this site that will help you with the settings. The main thing is location location location and a lot of luck. It would have been more fair had you known all this before you spent the big bucks.

 

[milcom_chaser]

I have locked out all but one site, turned attenuation on, AGC off, and running a stubby antenna consisting of a BNC female with a resistor lead pig tail that is about 1cm in length. Have adjusted DSP, ADC, DAC too many times. Even tried changing the site from NFM to FM even though that would defeat the purpose of Narrowbanding for 6.25khz slots. So this radio is distilled down to single site, phase II trunking, no LSM. Yet still, during audio decode, it cuts out or clips...

 

[SOFA_KING]

I have one 800 simulcast county just south of me that can't be clearly monitored on anything but a x36 scanner set to MANUAL 10. That works perfect ANYWHERE in that county, as well as my home area out of the county. My TRX-2 DSP level can't be adjusted to work the same. The problem, as I see it, is the "AUTO" algorithm. When you have phase distortion (due to multipath), or weak signal, these AUTO sensing adjustments go whacky, and there is where dropouts occur. The MANUAL adjustment on the Uniden x36 (exclusive) allows you to center the modulation peaks on an optimal fixed center...thereby eliminating any "AUTO" drift as it attempts to hunt for a better setting. Are there some systems that are so out of phase that even MANUAL threshold settings don't work? Some people do report that, although I have not encountered one in my travels yet.

After watching the AUTO threshold BER measurements work on my 536, and doing extensive weak signal testing down to ZERO bars of signal, I have concluded MANUAL 9 was optimal for VHF and most UHF systems I listened to. 700 and 800 systems leaned towards MANUAL 10 for lowest BER. I will say some individual 800 transmitters in my county were out of this spec, and those same radios reproduced the same results every transmission, so those radios must be out of spec. I work in the industry, so trust me...it happens.

As for my testing with my WS1080, PSR-800 and TRX-2, the best DSP setting I was able to "sort of" see any weak signal P25 improvement with on distant VHF signals was 74. And I did go further above and below the default and noticed more "Donald-Ducking" given a fair amount of signal as I got away from 74. Did I have a big difference at 73 or 75? No, but after testing the more severe dropoff limits above and below 74, it ended up centering on 74. As for 800, that value also seemed to work, but nothing worked for LSM issues. And all my tests, accept final mobile tests, were done on a fixed outdoor Diamond Discone antenna with FM broadcast filtering in place. I compare all my scanners side by side using a Stridsberg multicoupler. Very stable test platform.

Phil

 

[skip0157]

Thank you sofa_king. I had used a setting of 100 and found the audio to be "nasally" you call it Donald Duck.

I set it at 74 and did see an improvement. Thanks again!