536 and degraded performance on M type II

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doctordave

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While doing some field testing of the 536 on Maryland's Eastern Shore, I experienced some quite unexpected difficulties in monitoring a few Motorola Type II digital 800 trunked systems.....specifically Harford County and the Upper Eastern Shore Consortium. Same troubles with the DE 800 systems of New Castle County and Kent County (DE). While driving in fairly rural areas, decoding rapidly fluctuated back and forth from great to very poor. The S meter seemed to dip down to low levels each time the decoding suffered and came right back up to a solid 5 bars when decoding recovered. I was not near any obvious cell towers, etc. It is worth noting that the Uniden 796/296/996 and the GRE radios have always handled these very well designed county/state systems phenomenally well - on the exact same routes of travel. Curiously, my 536 was handling comparable type II systems in Howard County MD and Anne Arundel County MD rather well during testing days ago.

I'll likely return to these same areas soon to try various forms of attenuation ... but the rapid shifts between great and poor reception isn't really classic for front end overload. All antenna connections are rock solid. The issues were confirmed on both of my vehicle's 536 radios. Any thoughts?
 

shonc182

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Just digital? I am starting to realize I have challenges w/ 2 separate Motorola Type II analog systems that I have never had a single issue with. Specifically Oregon - Portland Public Safety and Washington County (OR). This weekend I started tracking missed and incomplete transmissions against my old scanner and it is alarming.
 

doctordave

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That is concerning. I only spent about 15 min monitoring a nearby analog Motorola 800 trunked system (Carroll County, MD) and there was plenty of back-and-forth chatter - but reception was stellar and I didn't note any indication of missed transmissions. Given your findings, I'll plan a side-by-side comparison with an older radio.
 

doctordave

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UPMAN,

Just FYI on this issue with some Motorola Type II digital systems, it is worth noting that the latest firmware upgrade issued for the 996XT degraded performance on many such systems for me.... compared with flawless 996XT performance on those systems before upgrading the firmware. Perhaps that tidbit will be of help in figuring some radio settings and/or firmware tweak.
 

whsbuss

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UPMAN,

Just FYI on this issue with some Motorola Type II digital systems, it is worth noting that the latest firmware upgrade issued for the 996XT degraded performance on many such systems for me.... compared with flawless 996XT performance on those systems before upgrading the firmware. Perhaps that tidbit will be of help in figuring some radio settings and/or firmware tweak.
I found the same results on the HP-1 when they released the latest f/w upgrade. The rebanding of my local P25 type II system help a "slight bit" but was better before the upgrade.
 

evan

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I have to agree. My 436HP actually does a worse job decoding the Nashville Metro Type II simulcast than any of my other GRE radios, which have never had any issues decoding it. Transmissions drop in and out while the other scanners continue to decode without any issue. Often the 436 doesn't even break squelch. The 436, however, does an excellent job decoding the Nashville P25 simulcast system. I also experienced the same degraded performance when I updated the firmware for my 996. Where I got improvements on P25 simulcast systems, I got worsening performance on the type II system I monitor.
 

whsbuss

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I have to agree. My 436HP actually does a worse job decoding the Nashville Metro Type II simulcast than any of my other GRE radios, which have never had any issues decoding it. Transmissions drop in and out while the other scanners continue to decode without any issue. Often the 436 doesn't even break squelch. The 436, however, does an excellent job decoding the Nashville P25 simulcast system. I also experienced the same degraded performance when I updated the firmware for my 996. Where I got improvements on P25 simulcast systems, I got worsening performance on the type II system I monitor.
Great observation! I'm experiencing the exact issues here. Someone said that Uniden probably used the Dallas P25 system for most of their testing..... but that is not a type II system.

Thanks.
 

doctordave

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I precisely replicated my in-jurisdiction mobile testing of monitoring various Motorola Type II digital systems again yesterday - see my initial post for prior results. Curiously, reception of the UES system / DE 800 systems was significantly improved yesterday and reception of the Harford Co system was MARKEDLY improved. The only thing that changed since the last test was the extraction of all non-CC frequencies from programming. Otherwise, all other system settings were completely unchanged. Peculiar. I suppose that there could have been some very strange atmospheric issues at play during my a prior test..... but these particular systems have been around a long time and I've never before noted any reception issues with other Uniden/GRE radios - they are "slam-dunk" systems to monitor from within the jurisdictions. Could the 536 be so slow at sorting through frequencies, that extracting non-CCs from the equation allowed significantly more prompt CC capture/processing and therefore a better "running start" at cleanly decoding the digital transmissions? Maybe. I'm going to make the drive through those particular jurisdictions again in the days ahead and see if performance remains consistent with the results of this most recent test.
 

AA6IO

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Very good information Doctordave. I am experencing some P25 decoding issues on my 536HP and 436HP with OCCS (Orange County) in So. Cal. As others in this thread have said, my GRE/RS scanners still do better. I am going to try the extract-all-but CCs that you mention on this system and see what happens.

Steve AA6IO (extra class, ham for 52 years)
 

K2JJS

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Could it be that in an effort to improve performance on the P25 simulcast systems (which I believe the latest firmware addressed in other scanners) settings were changed that effected reception on other systems? Just a thought.
 

doctordave

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Good question, K2JJS. I just referenced this on another thread - my side-by-side testing (this AM) of 536 radios with factory-vs-new FW yields no obvious difference in performance/audio on a Motorola digital type II system or on a Phase I system.
 
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