Subject: [NEXTEL-1] Poll: Is APCO-25 an appropriate technology for Public Safety?

From: Marcel <[email-masked]>
Date: Wed, 15 Jan 2003 15:02:50 -0500

-------- Original Message --------
From: "Lindsay C. Blanton" <[email-masked]>
Subject: RE: Poll: Is APCO-25 an appropriate technology for Public Safety?

Glen, sorry about the delayed response, but my schedule has been fairly hectic this week. 
My follow-up comments are listed below:

>> Greetings! Lindsay,

>> What do you do down there in SA?

Glen, my primary job here in San Antonio is as a financial planner.  I manage
trunkedradio.net to "stay in the game."  ;-)

>- voice delay in multi-radio environments

>> I am not sure what you are referring to here. There is noticeable

>> processing delay if two radios are within ear shot of on another, which

>> can be annoying. The practical solution to is simply to conduct "simplex,

>> radio to radio operations" in analogue.

Yes, this is what I was referring to.  This noticeable processing delay is a real pain for
public safety officials who are all congregated on a scene.   Speaking into the mike, and
hearing yourself 1/2 sec later around the scene is somewhat disturbing to the human mind. 

The practical solution to conduct simplex operations really doesn't fit the intention or
model of the Project-25 standard, since the original intention of Project-25 is to reduce
usage of bandwidth for public safety communications models.  Exceptions for analog will
negate the reason to have a digital standard in the first place.

>- high intensity voice handling (structure fire responses, foot pursuits

>etc.)

>>Again, I am not sure to what you are referring here.

What I refer to is:

1.  On Scene Fireground communications.  Ambient noise levels are extremely high, and
signal strengths are low inside structures.  On a fireground, a crew tends to "scream"
into a radio, not hold it 2 inches from the face and talk gently.  IMHO, the IMBE vocoder
does not do a good job of "reproduction" in these environments.

2.  Ever heard an officer chase a suspect 10 blocks, in touch with a dispatcher, over a
Project 25 network?    Ask a seasoned police dispatcher who works with a Project-25 system
and they'll tell you it is extremely difficult to understand the pursuing officer. 
Furthermore, as an officer gets into a remote area (creek bed etc.) where signals are
notoriously low, many times signal strength is low enough that the vocoder can't recover 
any voice frames.  In most cases, analog will make it through enough to allow the
dispatcher to get required info.

Project-25 signals do an outstanding job in low signal strength environments.  The vocoder
is able to use error correction to recover voice frames that otherwise would generate a
minor static on an analog signal.  BUT, when you get to *very* low signal strength
environments, Project-25 doesn't make it through at all, whereas an analog signal might
barely make it to the repeater, but it still makes it, and a dispatcher's trained ear is
able to do a MUCH better job of voice recovery than any vocoder on the market today.

To expand upon this further.  The IMBE vocoder does a very poor job of conveying voice
emotion, which is an integral part of the public safety communications process.  The
subtle nuances that are involved between officer/dispatcher communications are huge, with
dispatchers trained to pickup on these and react accordingly.   In fact, ask any
professional scanner listeners (yes, there are some!) and they'll tell you they can listen
to 10 different scanners at once and "pick out" a high priority distress incident in
progress.  A dispatcher is no differnt.  The IMBE vocoder  masks these nuances.

..and I'll go even further.  Co-channel interference.   Ever heard 2 units at once
transmit at the same time on a Project-25 network?  Physics doesn't allow it.  Remember
the days of Motorola Smartnet analog systems, where admins had the choice of deploying the
system in "message" or "transmission" trunking formats.  Transmission trunking was always
chosen over message trunking, because officers complained they could not transmit if
someone else was on the air.   2 analog transmissions at the same time might cause a
"Warble" or "masking", but a  trained dispatcher can typically determine who transmitted,
and pick out some of the details.  That can sometimes mean the difference between life and
death.

>- all or nothing coverage

>> It is a commonly held perception among the uninformed, that digital

>> coverage ends without warning. In reality, there is plenty of warning for

>> the end of your coverage... IF... you are trained to recognize it.

Yes, understood here.  In fact, Motorola's product line of Project-25 subscriber equipment
provides features  which can indicate this to the user (audibly).  

>Has

>APCO-25 *really* accomplished what the end-user (dispatcher, PD officer,

>FF etc) needs to do his job in a *more* effective manner?

>>Absolutely.

If your response of "absolutely" is in regards to the above, then, I respectfully
disagree.  I don't believe that APCO-25 has provided to the end-user any additional
functionality.  The only difference your average firefighter or police officer sees is,
well, everything that I have described above.  If you mean Project-25  provides greater
interoperability, then I really disagree.  Many vendors and agencies have publicly snubbed
the Project-25 standard.  Just look at how my home town, San Antonio TX, has chosen the
path of an EDACS ProVoice  system.  Even the state of FL has decided to dismantle a
Project-25 statewide system in favor of a Proprietary solution, EDACS ProVoice.  Although
the MA/COM solution is based on the same IMBE vocoder, it doesn't help for statwide
interoperability.

Side Note:  I am pretty sure that MA/Com is now providing Project-25 Conventional
capability on their newer subscriber units, so I suppose that helps.

>Scanner listeners, public safety professionals, and system managers all

>participate actively on trunkedradio.net, so I'd say we've got a very

>enlightening cross-section of the community to take a pulse from.

>> I don't so I can't comment on the "enlightenment" of the group. My

>> supposition is that the group parallels others on the net...running from

>> the "erudite and highly capable" all the way to the "hopelessly uninformed

>> and totally ignorant".

We are in total agreement here.

>> As far as I know, the 6.25 KHz. FDMA part of P25 is standardized. Only

>> the TDMA implementation is still unsettled. That appears to mired in a

>> battle between various supporters of 2 slot vs. 4 slot vs. 12.5 KHz vs. 25

>> KHz. including, but not limited to, Tetra like and multi-channel JPM

>> modes. Only the Power above knows when or if that will be resolved.

Oh Boy, another standard.  ;-)

>Can you share with us your thoughts and experiences?

>> I think I just did.

This has been a great discussion, and I enjoy the discourse.   I do want to make it clear
that I *do* support the Project-25 standard, and I feel that it *is* needed.  Bandwidth is
only going to get smaller, so there isn't going to be a choice but to move to more digital
mediums for public safety communications.  BUT.... well, read my comments above.

Warmest regards to all,

Lindsay

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

---

From: Marcel <[email-masked]>
Date: Fri, 17 Jan 2003 11:39:38 -0500

-------- Original Message --------
From: Don Root <[email-masked]>
Subject: Re:Poll: Is APCO-25 an appropriate technology for Public Safety?

Hess, Dave R. wrote:
> I guess I am not making myself clear.  It has never been more critical 
> for all of us to be able to communicate across our different agencies.  
> We now have more problems than ever doing that.  You can not deny that 
> and have any credibility with the techs and users struggling to 
> communicate.  Digital modulation, narrow banding and encryption  may 
> solve some problems, but what is being done about the problems created 
> by such devices?  Call me a cynic.  Call me old school.  All I want is 
> for my customers (LASD) to be able to do their job safely with the 
> radios we provide.  With 88 incorporated cities (24 over 75,000) and 
> nearly 10 million souls depending on us, I take this job seriously and 
> don't mind the flak from saying the obvious - it's not working!!! Dv
> P.S. Last post...... I got work to do.

OK. Dave, you are old school.  *Your customer* is leading the effort to 
improve interoperability in LA County, by chairing a multi-million 
dollar effort to develop capabilities. LASD recognizes digital is a 
thing of the future, and also recognizes that digital technology is 
maturing. Yes, there are problems. They are being addressed and worked 
through.

Don

---

From: Marcel <[email-masked]>
Date: Tue, 21 Jan 2003 18:42:07 -0500

------- Original Message --------
From: John Powell <[email-masked]>
Subject: Re: Poll: Is APCO-25 an appropriate technologyfor Public Safety?

Unfortunately, except to the degree that they are directed otherwise by 
Congress, you are generally correct with regard to the FCC's lack of 
concern for interoperability.  Yes, there are some within the Commission 
who realize that interoperability is a very critical issue for public 
safety, but they are not typically on the 8th floor.  That said, the FCC 
has no control over Project 25 other than accepting (or more often not 
accepting) the technologies and implementation time frames that we in the 
user community have proposed over the years.  NTIA has had more involvement 
with P25 because they have had direct representation on the Steering 
Committee, and the federal user agencies clearly have a better grasp of the 
benefits and drawbacks of digital than the FCC and many local/state 
agencies for that matter.

With the 700 MHz band, the Commission was directed to implement a standard 
for interoperability.  They chose to make the band digital with spectrum 
efficiency being their driving force, and were thus forced to accept P25 as 
the only accredited standard readily available, with P25 also being the 
overwhelming choice of the user community in response to the various public 
notices on implementing this band, and the recommendation of the NCC, the 
FACA-chartered committee established by the FCC to help it resolve the many 
issues surrounding implementation of this new public safety band.

While digital carries with it all of the attributes you describe in your 
text, it also adds user services that our community requires and that are 
not available from analog technologies.  Yes, many argue that it comes with 
a high price tag, but let's look at that more closely.  How many of us 
thought nothing of paying up to $2000 for an 8-channel crystal-controlled 
Motorola MT-500 portable 12 years ago.  I would suggest that, when 
inflation is considered, that simple analog radio (and yes, it was probably 
one of the best ever produced) cost at least as much as a full-featured P25 
conventional and trunking radio covering both the 700 MHz and 800 MHz bands 
today.  Yes, today's simple analog radios offer many more features than 
that MT-500 and at a much lower price, but that is the state of technology 
production today.  As with other industries (pharmaceutical companies, for 
example), radio manufacturers have a right to recover their R&D costs, and 
that means we pay more for new technology in its first generations of 
production; if they didn't, there would be no new stuff.

Again, P25 does what it does because users wanted it.  It exists in 
compliance with FCC Rules and Regulations, but not because of them.  Phase 
II TDMA (Phase I FDMA is already completed) and any later phases to follow 
will be the same.

John Powell

At 10:33 AM 1/21/2003 -0700, Byron Schmidt wrote:
>Mr. Powell,
>   Yes, interoperability, is one of the issues, clearly.  But the FCC or NTIA
>doesn't care what your interoperability issues are per se.  That is a user
>problem.  To the extent that P25 allows for greater contact among agencies,
>it is a good thing I guess.  But again the Feds are looking at jamming as
>many users into the space available.  That is a requirement that will not go
>away and will become more of an issues as more users come on line.  So the
>digital methodology is the only game in town and explains the complexity
>over analog.  This is not necessarily a bad thing.  Filtering in the digital
>domain is much more efficient and the parameters can me more tightly
>controlled over their analog counterparts.  That is one reason we are here,
>and the complexity is part of the equation that will not go away.  This is
>good for us to discuss, and I am glad that we are.  But are there other
>issues out there for you?
>
>Byron L. Schmidt, DAFC, GS-11
>Deputy State Director
>CAP-USAF Liaison Office. Idaho
>208-345-8263 - (Voice)
>208-333-8247 - (FAX)
>[email-masked]

---

From: Marcel <[email-masked]>
Date: Wed, 22 Jan 2003 15:19:01 -0500

------- Original Message --------
   From: "Todd Ellis" <[email-masked]>
Subject: RE: Poll: Is APCO-25 An Appropriate Technology for Public Safety?

 John:I have used a 220 ACSB mobile radio at speeds some in the law enforcement field
would probably not like to know about.  Speed had nothing to do with the operation of the
radio at all.  Perhaps Washington State was using an old Aerotron VHF unit from the early
90s for experimental use, I don't know.  The difference in technology between then and now
is that DSP is heavily used, where back then it hadn't been utilized yet.I would say that
back about 12 years ago when EFJ first started selling 900 equipment at 12.5, there were
issues relating to components and shock/vibration elements.We have also seen clients
crossband using audio levels (4-wire E&M) from FM systems to ACSB and back with little
issue.  I think something like the ACS-1000 from JPS is a great tool for that kind of
utilization between techologies, including P25 if necessary.

Todd Ellis
Operations Manager, Telecommunications Division
Booth & Associates, Inc., a Utility Services Associates company
An Employee-Owned Business
1011 Schaub Drive, Raleigh, NC 27606
Phone: (919) 851-8770, ext. 109  Fax:  (919) 859-5918
Cellular:  (919) 418-3358  Alpha Pager:  (877) 205-9320
E-mail:  [email-masked]
Two-way SMS: [email-masked]
Web:  www.booth-assoc.com
Telecommunications, Transmission & Distribution, System Planning and Special Projects,
Mapping and Field Services, Substations & Relaying, Strategic & Financial Services