Use 'ATT' button to improve audio of digital systems in areas of RF

[dizwiz]

Some people are probably reading this and saying 'duh' but I did want to point this out to any newbies (like myself) who previously was doing stuff like putting better (800 mhz dedicated) antennas to try and get better decode of digital audio.

For years (even going back to 2004 when I got my Uniden BC296D) I had issues with decoding (esp. when mobile) of 800 MHZ digital audio.

A transmission would sound like 'Unit 286, I need a <beep gargle, crunk crunk> assist me with <beep blah > etc.

A call to an idiot uniden rep told me that was encryption. Yawn. I told him that then why do I hear the beginning of the sentence? He told me well they sometimes start talking and then flip the encrypt switch mid-sentence. Sure......okay (rolleyes).

In reality, most of this was the front end of the scanner getting overloaded by another 800 mhz site being a cell-tower (very common on highways, etc.)

Ive found that using the 'ATT' whenever I start to hear a conversation go digital on me can restore the audio clarity. Especially if Im in an 'urban area' or note power lines or 800 MHz cell towers nearby.

 

[eorange]

Good point. Quite a few of us in NE Ohio are battling simulcast garble issues with some new P25 systems that have come online. There is no magic bullet, but experimenting with ATT on the PSR-500 is at least something I've been trying.

 

[Swipesy]

Those of us who live in NE Ohio have the advanatage (or disadvantage as the case may be) to monitor 3 distinct P-25 systems. Being able to monitor these systems lets us develop some benchmarks and strong opinions about the monitoring radios we use to monitor these systems. For the past month I have been using a PSR 800 that replaced my PSR 500 to monitor these systems. I also was fortunate to have been able to borrow a Motorola XTS 5000 for a week that is being used on the MARCS P-25 system. Also, being retired I am able to move around NE Ohio and monitor these systems from different locations. For what it is worth (this site is free) here is my take.

Point 1 - The PSR 500 and PSR 800 (I do not have a Uniden product) are inferior (as compared to a XTS 5000) in hardware decoding of P-25 systems. The MARCS P-25 System for the most part is just horrible on an 800 and 500 while side by side with the XTS 5000 all transmissions were understandable on the 5000, though at times iffy. We as hobbiest are stuck with "inferior" hardware because of the price limitation. I am not sure that the scanner manufacturers could strip out enough features from these radios and put in better hardware or not. That is out of my area of expertise.

Point 2 - In NE Ohio, the Parma P-25 System and the Bath P-25 systems are far more clearer on the 500 and 800 which says that these two systems obviously are setup differently than the MARCS P-25 system and our radios handle the decoding much better. Obviously MARCS is not going to change their setups for the benefit of scanner hobbist and I am afraid that those of us in NE Ohio are stuck with what we have.

Point 3 - I have been playing around with Advanced Settings on the 800 and have spoken to GRE several times about how to adjust the settings but GRE offers no help. They just keep quoting the Manual. I hit upon one setting that seems to work a little better, and I posted in the Ohio forum, and asked others to test also, but to date there has been no feedback on my suggested setting.

All in all I think Points 1 & 2 is what it is and no amount of adjusting the radios is going to gives us the voice clarity that we are used to on analog trunking or UHF/VHF systems.

John

 

[pratzert]

One of the things on my scanner "wish list" is for the Scanner Mfgs to come up with a fix, or even a new scanner, that is capable of receiving P25 Simulcast CLEARLY.

I'm not in any hurry to have to invest even MORE money in scanning eqpt, but since my area went P25 simulcast, the hobby has not been the same for me.

 

[dizwiz]

the point of my post is that the 'ATT' setting can be a 'tool' (under certain circumstances) that improves audio decode of P25 digital transmission.

ATT's benefits on an analog 800 MHZ (ex. Franklin county's) system are real obvious as the 'fuzz' decreases and voice gets clearer when you hit the ATT button.

However, I was always assuming partial (incomplete) decode was a weak (distant) signal issue.

In reality, sometimes its an interference issue.

Whenever I get near that I-270 circle, I hit the ATT button for every 800 MHZ system I monitor (Franklin county, OH MARCS) and I have the best luck with hearing on my PSR-500. Though still not perfect

Sometimes I hear a garbled transmission and hear the dispatcher say 'repeat you went digital'. I love it when this happens because it means it wasnt just the PSR-500 that had trouble.

 

[jackj]

Yes dizwiz, the ATT button is a tool. But it can only help with some decoding problems, those caused by signal overload. It can also help with noisy analog signals IF the noise is caused by strong, near-by signals. But if your decoding problems or noise isn't caused by signal overload then the 'attenuator' won't help, it may even make things worse.

Swipesy, it doesn't cost a manufacturer more to build a high quality circuit than a low quality one. Given today's state-of-the-art, direct production costs are very low for almost any IC. The costs come into play when you have to buy a license to produce the circuit. Motorola owns patents on most of the production circuits used in their equipment and they won't license them to anyone. If you want the performance of their circuits then you buy their products. Maybe when those patents expire we will be able to buy scanners that work as well as today's commercial equipment.

 

[Swipesy]

Jackj

Thanks for providing that info on the IC chip. One thing I learned from the side by side comparsion was that digital is digital and the sound even on the XTS 5000 was not as great as analog. Maybe some day the engineers will figure out how to clear up the bad sound of digital transmissions.

John

 

[IowaGuy1603]

Jackj

Thanks for providing that info on the IC chip. One thing I learned from the side by side comparsion was that digital is digital and the sound even on the XTS 5000 was not as great as analog. Maybe some day the engineers will figure out how to clear up the bad sound of digital transmissions.

John

I find when I monitor both P25 digital systems in my area that the officers are also telling each other that their signal is garbled......One is a Motorla system and one is a Harris.......
One multisite and one is simlucast.

 

[tilt404]

for me the main improvement i got was by getting a outside antenna, a comet discone, lmr400 and about 90% of my P25 Phase I Simulcast terrible audio went away and the voice cleared. its been so much better now where before using a decent watson whip on the PSR800 inside at my desk was ok, but the voice audio was often hard to understand. money well spent for me since i actually enjoy listening again. the rare time i can't understand what they are saying, the dispatcher will also ask who's talking to repeat since they can't understand them either. the att button helped a bit for me though before when just using the whip. but so much better now with the discone outside.