Tried out my new PRO96 in Boston

[Chris-M]

I had a trip up to Boston and an overnight so I brought my PRO96. I used the VScanner feature and loaded the local data. I was able to hear a lot of digital APCO activity on the http://www.radioreference.com/modules.php?name=RR&aid=1233 NH State Police system, being that I was close to the state line. Overall the scanner performed as I expected, and on occasion I had to move the scanner a few inches to a different location to find the signal again. What I mean by that is, while holding the scanner while monitoring, if I moved the scanner a few inches it would lose the signal and you couldn't understand the transmission (digital). When it receives the signal strong, the audio quality is very good.
I'm curious if there are potential problems in the field to users of the system. In fringe areas, or between buildings, etc where the signal is weaker, I'll bet that a digital signal will be unreadable before an analog FM one would be affected.
I'm not looking forward to the digital age but at least for now I'm ready when it gets to my area. That is, so long as it's MO APCO25.

 

[Thayne]

Here in Colo I hear every day many times dispatchers say "You were digital, try again"--so yes there are problems. I guess we are becoming a nation of people that accept almost anything.

I bet VOIP will be next; once all the old people die off nobody will remember that telephones were once crystal clear-- :roll:

 

[SCPD]

Guys,

have you compared the quality of an analog signal with the same RSSI reading?

IMBE was designed so that it could work right down into the mud. I've used IMBE to communicate, where analog was almost 100% useless.

Would be guys be complaining if this was 1985 and you were listening to the first UHF analog system your virgin ears had ever experienced? Just think of all the static!

I may post some results for you (actual digital/analog audio recordings from the same station using analog/digital to compare) in the next week or two.

S

 

[Thayne]

I am an old fart, but I don't remember any audio degradation when systems were switched from VHF to UHF. I remember how VHF Lo used to have funny effects from skip and ducting; those problems went away when 152-172 and 450-470 bands came into wide usage.

IMHO, With analog systems, the loss of audio is more linear from good to bad, while digital systems can become unintelligible and back again in a few seconds just from moving a portable around a few inches or feet.

I agree that digital sounds better when everything is perfect, but a portable on somebodys' belt does not represent optimum radio propagation; so what do you mean by "Down in the mud"?

Anyway, digital is here to stay--thats for sure

 

[SCPD]

Hey,

What you guys are forgetting is that digital signals get weak too! Digital systems will work fine with weak digital signals, that's what error correction is for. On an analog system, the weak signal sounds like static. Sometimes on a digital system, there is no packet loss (garbled audio) even when the signal is weak, when on the analog system there's a lot of static present.

When a digital system starts to sound like crap, you're on the very fringe of the coverage area, and I do mean the fringe. If you were listening to an analog signal of the same signal strength, you most likely wouldn't be able to make anything out at all.

When you move your radio a few inches (when receiving a weak signal) of course it will fade in/out. An analog system on the fringe will do this too. When you hear an officer who's getting into the system very poorly (i.e. breaking up on the input of the TRS or conventional repeater) chances are if he was on analog he wouldn't even be getting in at all. With digital trunking, at least the dispatcher can see the Radio ID of who's calling, rather than taking a guess with an analog system.

It's also not fair to compare the results of your portable scanner (receiver sensitivity of 0.4 - 0.8uV for 12dB SINAD in most cases) to that of an XTS3000 which has 0.21uV for 12dB SINAD or better. I also know for a fact that the DSP 8.xx.xx firmware present in current XTS3000/Digital Saber/Digital Spectra radios, does a better job at error correction/recovery than that of the PRO-96. I'm not trying to sound like an elitist or anything, just stating the facts.

Once I post the samples/tests, you guys will have a much better understanding of what I'm talking about. Give me a few weeks, my partner in crime is on holidays right now, and I'll need his assistance for a coordinated test. I'll be posting an audio file.

In the mean time, here's a series of tests/results from the US Government:

http://flattop.its.bldrdoc.gov/spectrum/P25/daq_sb/daq_sb.htm

Test results from back then, my vary slightly with results now, as DSP6 was the only DSP firmware available to test with back then. DSP8 is a huge improvement.

(Thanks to Josh on batlabs for posting that in my semi-related thread there: http://batboard.batlabs.com/viewtopic.php?t=35399 )

S

 

[Thayne]

Boy Shaun, I will need more coffee before I can get very far into that chart you linked (Just put on a new pot)

As far as analog trunked systems, the dispatcher can see the LID of any radio that has affiliated, no? because the CCs' are digital anyway, right.?

I don't disagree with you as far as the theoretical superiority of digital, thats why CD's replaced phonograph records.

Also the better use of available spectrum is compelling.

All I'm saying is that MANY users on the COLO DTRS do not see the performance being as good as the older trunked analog systems.

I think this is because Your beloved MOTO made optimistic promises to get the job; (Just as MA/Com would do too)

Another telling thing to me is that most of the urban sites were just changed to digital operation, USING THE SAME FREQS AND SITES as the old 3600 MOTO system, yet it doesn't work as good. Please explain that??

 

[SCPD]

As far as analog trunked systems, the dispatcher can see the LID of any radio that has affiliated, no? because the CCs' are digital anyway, right.?

Dispatchers cannot see actual affiliations, unless they're using an aftermarket product like "trunker" or Motorola's "System Watch II". Most (99.99999%) of dispatchers have no idea what affiliation means.

All I'm saying is that MANY users on the COLO DTRS do not see the performance being as good as the older trunked analog systems.

I think this is because Your beloved MOTO made optimistic promises to get the job; (Just as MA/Com would do too)

Another telling thing to me is that most of the urban sites were just changed to digital operation, USING THE SAME FREQS AND SITES as the old 3600 MOTO system, yet it doesn't work as good. Please explain that??

I have no experience/knowledge with the system you describe, but it's quite common for people to be picky about a new product/technology. They never comment on the good aspects, nor do they show praise for them. They simply focus on negative things and get this "brainwashed mentality" that the system is horrible and not safe simply because one of their fellow officers/firemen/whoever was trying to use their radio with a broken antenna or in a parkcade somewhere, and didn't make it into the TRS.

The system users are often the trouble themselves. - Yes I know it's easy to put the blame on them, but it's so true. Up here we call them the DFU's (Dumb F...... Users) as they don't know how to use their equipment properly, then blame it on the administrators and engineers. Do you honestly expect your portable to work in a parkcade 5 miles from the tower when you're holding your antenna horizontal? Perhaps on your belt?

There's a simple fix for all systems that exhibit poor coverage; ADD MORE SITES. This is not practical as it's cost prohibitive to do so. In the instance of some systems, Motorola engineers suggested "10" sites for example, then the cheap politicians only budget for "3" sites. The result is bad coverage, poor performance, and dead spots. But of course, it's the "radios" that are bad. "These radios are crap" is a common complaint up here.

No system is 100% perfect. If engineers had unlimited funds to spend when constructing the systems, they'd be a lot better. But cost cutting and budget limitations (politics) always get in the way.

If you're a public safety member, the best thing you could do to help get the system fixed is note the location of your performance problems, and if possible the RSSI and Site # (Or name if using omnilink with aliasing) then provide that information to the radio shop. No doubt the radio shop and engineering groups have done a lot of pre-installation tests for coverage, but it's entirely possible they've missed a few spots. The only way for them to get more $ to put up more sites is to have valid complaints from the users, and documentation to back those complaints up.

S

 

[Thayne]

Ah heck, I don't want to argue back & forth, and I have much respect of your MOTO knowledge as Demonstrated on the BATBOARD--but my main OPINIONS and 1 FACT still are : 1. (Fact) My OLD Analog GE MPA shows LID's as they transmit on the system. 2. I don't believe most of the problems can blamed on the users. 3. I think MOTO stuff is not any better than MA\COM and is MORE overpriced and difficult than most to program. Otherwise, I pretty much agree with you :shock:

 

[SCPD]

Ah heck, I don't want to argue back & forth, and I have much respect of your MOTO knowledge as Demonstrated on the BATBOARD--but my main OPINIONS and 1 FACT still are : 1. (Fact) My OLD Analog GE MPA shows LID's as they transmit on the system. 2. I don't believe most of the problems can blamed on the users. 3. I think MOTO stuff is not any better than MA\COM and is MORE overpriced and difficult than most to program. Otherwise, I pretty much agree with you :shock:

Hey Thayne,

I didn't mean to sound like I was arguing, sorry!

Hey, what's a LID? I've never heard that term before. I thought you meant RID and LID was a typo. The only place I've heard "LID" was on ham radio. _Some_ of the old farts like to call bad operators LID's.

Motorola's products are EXTREMELY overpriced. I'm very fed up with having to pay $4.50 for a small plastic button, or $10 for a sticker! But M is M. Love them, or leave them

Most system problems can be attributed to poor end-user training. When I'm investigating an alleged "system problem", and can't replicate it, I often say to myself, "Ok, think like a complete idiot. Use the radio like an ape would!" (Even then I have troubles because apes tend to be smarter than the DFU's who complain to us.)

End users are not radio smart. A very small percentage of police/fire/ems people have an interest in radio like we do - they are the exception. It's unfortunate that they're not trained (or don't want to learn?) to use the system/radios the way it was designed to be operated. Many problems could be avoided..

- Low audio (SPEAK UP FOOL!!! HOLD THE MIC CLOSER TO YOUR MOUTH)
- Speaking before the transmit permit tone is finished
- Letting go of the PTT before finishing your transmission
- Not charging your battery properly, and/or not carrying a spare
- Not reporting trauma to the radio, or using damaged equipment (loose speaker-mic cords CAUSE HELL.. Can lock up a system (PTT line gets grounded out) and can contribute to very noisy audio if the audio line is intermittent)
- User isn't trained on proper usage of channels/talkgroups. "Claims they can't communicate with xxx. Radio is crap." WELL HOW ABOUT SWITCH TO THE RIGHT TALKGROUP FIRST?!?!
- User constantly plays with the volume knob, thus missing calls due to low RX volume. (Interestingly, some users have said they turn the volume down due to excessively loud talkers on the system, which is a condition that's prevented by enabling the AGC feature of the radio, something many admins neglect to do because they're too damn stupid)

Enough whining from me. I should really get back to what I was doing..

S

 

[Thayne]

LID (Logical ID) is a number that EDACS systems use to ID Each radio on the system.
I assumed MOTO used the same thing--

I think I might have a bias against MOTO because an old unnamed retired sheriff around here used to express his usually ignorant opinions EVERY MORNING at the restaurant all of us dedicated taxpayers servants went to for breakfast.

I could tell he thought the sun rose in MOTOs' you know what--- :wink:

 

[KG0MX]

Here's my observation from listening to the washington d.c. metro police for a number of years..........

Old analog system, dispatchers would periodically say "10-9, you were broken up".

New digital system, dispatchers are *frequently* saying "10-9, you were broken up".

The simple issue with this particular system is that it just plain sucks compared to the old analog system......and the troops on foot and in the patrol cars have colorfully expressed their discontent for this system.

Anyway, my 1/2cent.

 

[SCPD]

Wasn't it the Washington system that had SERIOUS coverage issues because local politicians skimped out on the number of towers Motorola engineers told them they needed?

I recall hearing all about this on batlabs a number of times.

S

 

[Thayne]

So to me that means digital must need more sites to work as good as the analog system it replaced, right??

We can't blame it all on the bulls--

 

[SCPD]

Thayne,

That's an incorrect statement. Digital has nothing to do with a poor system design. You get what you pay for.

Let's take cellular systems for example.

Do you think you can have 100% coverage of DC with 3 towers? (example, facts are unknown.) Of course not. Do you think you could accomplish the same thing with analog? Nope.

I'm getting a little tired of discussing this topic. A system will work only as well as it's designed. That goes for any system. If you do things the cheap way, of course the performance will be crap.

I think the users are hypersensitive to the issue of digital packet loss. They're so used to hearing static and nobody says anything.. Then you experience a digital signal breaking up, and all of a sudden the system is crap? I don't think so!!!!!

Another issue I forgot to mention.. On portable radios, many departments love using those little STUBBY antennas. You CANNOT use those. They are GARBAGE. THEY DON'T WORK WORTH A DAMN! On a 800 MHz system, you must go with the 7" 1/2 wave antennas. The 1/2 is a very efficient antenna to begin with (doesn't require a ground plane) and it's almost perfectly matched to the transmitter.

S

 

[Thayne]

It's a real paradox, ain't it? :?

We can't get any more meat off that rabbitt

 

[SCPD]

Nah, I could go all night long if you want I just don't see the point as it's not going to change anything, and I'm not entirely sure you guys follow 100% of what I'm saying.

S

 

[KG0MX]

Yeah Shaun.....we're all idiots, and you're perfect.

 

[Thayne]

I would rather listen to a voice trying to stay above static, than what sounds like PeeWee Herman with a Taser in his butt-- :?

Also, Shaun--it sounds like you should remind yourself that it is your job to make it easy for all those "Idiots" you work for to communicate with each other--so you can keep your access to all that MOTO Astro stuff

 

[SCPD]

Yeah Shaun.....we're all idiots, and you're perfect.

I didn't say that you hamsexy. Don't put words in my mouth, and I won't put my foot in your arse.

 

[SCPD]

I would rather listen to a voice trying to stay above static, than what sounds like PeeWee Herman with a Taser in his butt-- :?

Also, Shaun--it sounds like you should remind yourself that it is your job to make it easy for all those "Idiots" you work for to communicate with each other--so you can keep your access to all that MOTO Astro stuff

You fail to understand you CANNOT HEAR THE VOICE at the signal level on analog that would be breaking up, which is comparable to digital starting to experience major packet loss.

S