996P2 fails Burbank/Culver City site test???

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AA6IO

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I want to preface this post by saying that your mileage will vary (YMWV) depending on where you live and what you scan. I bought a 996P2 the other day and am just getting around to making some comparisons with my 996XT and 536HP.
I have used the 996XT for years, and it is a solid performer, with lots of nice features. My first few days with the 996P2 seems to indicate performance like that of the 996XT, very good. But unfortunately, at least here in my QTH in Cerritos, about 20 miles SE of Los Angeles, the 996P2, like the 996XT, can't pass the Burbank/Culver City site test.
These sites are part of LA ICIS, a Motorola Type 2 Mixed Analog/Digital system, with mostly digital TGs. Its sister LA ICIS P25 system is a Project P25 system (all digital). Both have many sites and cover a wide area of Los Angeles County.
From my location, the Glendale and Montebello site control channels on LA ICIS are always strong. All of my digital scanners do a very good job on these sites, including my 996XT, 996P2, and my GRE/RS/Whistler.
Burbank is about 25 miles away and Culver City, about 20 miles, not particularly distant, but these sites are more limited in area, at least I don't usually receive them that well with a mini discone. My 440 Yagi is another story, no problem.
So one of my tests for how well scanners decode P25 is to lock on to the Burbank and Culver City sites using a marginal antenna, and see how well weaker P25 channels/TGs are decoded. The 436HP and 536HP consistently are able to decode these weaker (about 1 bar) P25 stations. That was the main difference I noticed with the 436HP/536HP vs 396XT/996XT.
At least from my early experience, the 996P2, as good as it is, still can't pass the Burbank/Culver City test. Using the same antenna via an MCA204M multicoupler, the 536HP is decoding P25 signals very well on these sites, despite a less than optimum CC signal, whereas the 996P2, like the 996XT, motorboat, stutter, or just don't decode any of these weaker signals.

I began to notice that the 996P2 stuttered occasionally, and drop out, on weaker LAPD channels. The 436HP/536HP decoded very reliably in almost all cases. So I went ahead and did this Burbank/Culver City test.

Again, this is only my limited experience in the Los Angeles basin, and for a short time with the 996P2. Perhaps tweaking of the P25 settings will help somewhat. But my initial impressions are that the x36HPs win in the weak P25 decode department. Of note, we have very few P25 Phase 2 stations active here. But in Las Vegas on the LVMPD P25 P2 system a couple of weeks ago, my 436HP/536HP were near perfect on decoding many sites and TGs in Vegas.

Again, YMWV with different scanners in different scenarios.

Steve AA6IO
 

Voyager

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Keep in mind that the x36 has a better filtering system, so if there are adjacent channel users (It's LA - there WILL be adjacent channel users), they will affect the XT/P2 series more than the x36 series. On weaker channels, you increase the chance of stronger adjacent signals, too.

But, as you said, it's all based on your RF surroundings.
 

AA6IO

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Voyager,
I think the filtering issue may be what is going on. The NFM filter on the x36HPs does help here.
For the 90% of signals that the 996P2/996XT decode clearly, the P25 sound is great. I actually prefer it to the bassy sound of the x36HPs. For people like us who want to play with a lot of different features, the x36HPs do offer them. But I suspect that if I asked 10 people who were non-scanner enthusiasts which sounded better, the 996P2/XT vs the 536HP, once the decoding issue has been removed, 8 or 9 might say they like the 996P2/XT. Actually, I am one of them.

Steve AA6IO
 

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This is the old issue of "tinny audio sounds more crisp", and "should audio be faithful or copyable".

What those mean is that audio that contains more bass will always sounds more 'muddy'. This has been proven over many decades. To help with this issue, legacy radio formats have stripped the audio below 300 Hz for purposes of stripping the signalling that exists. With P25 (or any other digital format) there is no such filtering, so the audio below 300 Hz is present. If you are used to the filtering, the audio will sound more bassy and less crisp.

The other half is a question which radio engineers have struggled with since radio was invented: Should a signal be more copyable, or should it reproduce exactly what is being transmitted? The preemphasis/deemphasis curves can be altered so the highs are emphasized more, which people say is more copyable. Others want to hear an accurate representation of a person's voice - they want the radio to sound as much like the person does face-to-face as possible. The two are at odds, and there is no "right" answer since it's all based on opinion. I happen to be of the latter camp. I believe there are tones and inflections that are removed without accurate representations over the radio, and what goes in is what should come out.

It's like arguing which shade of green is "better". There is no right answer.
 

Boatanchor

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Bottom line:

No digital scanner produced in the last ten years should have left the production line without NFM filtering!

It's an addition $5 cost to the component inventory on a $400+ scanner.

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I've deleted everything below this line - my comments were irrelevant / off topic -
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jonwienke

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Bottom line:

No digital scanner produced in the last ten years should have left the production line without NFM filtering!

It's an addition $5 cost to the component inventory on a $400+ scanner.

It's not just the filter, there's also support circuitry needed to switch the IF between the FM, NFM, and WFM filters. Every additional filter makes the support and switching circuitry more complex and expensive.
 

Boatanchor

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It's not just the filter, there's also support circuitry needed to switch the IF between the FM, NFM, and WFM filters. Every additional filter makes the support and switching circuitry more complex and expensive.

Yes, a couple of 5c SMD switching tranistors, a few 1c SMD resistors and an extra control line.
The additional $5 component cost estimate included these components.
 
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