New GSP mobile repeaters

[procopper7005]

I'm in Barrow County and I still hear GSP activity on 154.68. That's the old base-to-car frequency for state troopers out in 'the sticks'. Pretty much everything out here (i.e. Barrow, Jackson and Oconee Counties) is still VHF Hi-band....and it really should stay that way. There is talk about a multi-county digital 800 TRS for Hall, Jackson, Barrow and Banks. But why? Isn't that why we have 'state band' on VHF? (i.e. 154.905, 154.935) Sorry, but rural counties in Georgia don't need 10 million dollar (and up) digital 800 systems. Just 'cause Gwinnett got one of them new fangled P25 systems, doesn't mean everyone else has to. VHF conventional is still proven and reliable technology. If it ain't broke, don't fix it. Just improve what you already have.

I agree, but GSP needs a better system. Local counties at least are using VHF repeaters. GSP is still using technology from the 1940's. All GSP needs is a non trunking (possibly P25) VHF statewide repeater system.
Trunking systems are for large metro areas that have thousands of units. Not mid size or small counties.
And for true reliability look at what LAPD and NYPD have. They dont use trunking systems for a reason.

 

[kc4wai]

That's right. NYPD and LAPD are both UHF-T band conventional. Although LAPD is P25 digital. NYPD hasn't gone digital and most likely won't be. They've been using the same frequencies since the early 70s. It would be a logistical nightmare for the 5 boroughs to undergo that sort of transition. Mayor Bloomberg has also made it pretty clear that the City of New York is sick of getting ripped off by Motorola.

As for GSP they could certainly beef up their infrastructure. VHF is fine for statewide coverage, but yes I agree a repeater network wouldn't hurt. Of course some would have us believe such a thing already exists in GEWIN. But that is nothing more than Cobb's TRS with MotoBridge. There is no GEWIN and never will be. Just like NC and the VIPER system. It's a pipe dream.

I know GSP used to be very active on 155.91 for metro Atlanta ops. But I believe that channel has gone silent. I believe they are currently using the Atlanta TRS for troopers in the metro area. I have no big desire to monitor (G)od's (S)pecial (P)eople really. All you'd probably hear is a lot of GCIC records checking....maybe the occasional DUI stop. Local cops are way more interesting to monitor.

 

[b7spectra]

That's right. NYPD and LAPD are both UHF-T band conventional. Although LAPD is P25 digital. NYPD hasn't gone digital and most likely won't be. They've been using the same frequencies since the early 70s. It would be a logistical nightmare for the 5 boroughs to undergo that sort of transition. Mayor Bloomberg has also made it pretty clear that the City of New York is sick of getting ripped off by Motorola.

Could one even imagine what Motherola would charge NYC to put in a DTRS? My, God, you are talking no less than $250million! And that's even before their cost over-rides and upgrades! Imagine how the stock holders would feel is Big M was able to STEAL a half Billion dollars from NYC!

 

[procopper7005]

That's right. NYPD and LAPD are both UHF-T band conventional. Although LAPD is P25 digital. NYPD hasn't gone digital and most likely won't be. They've been using the same frequencies since the early 70s. It would be a logistical nightmare for the 5 boroughs to undergo that sort of transition. Mayor Bloomberg has also made it pretty clear that the City of New York is sick of getting ripped off by Motorola.

As for GSP they could certainly beef up their infrastructure. VHF is fine for statewide coverage, but yes I agree a repeater network wouldn't hurt. Of course some would have us believe such a thing already exists in GEWIN. But that is nothing more than Cobb's TRS with MotoBridge. There is no GEWIN and never will be. Just like NC and the VIPER system. It's a pipe dream.

I know GSP used to be very active on 155.91 for metro Atlanta ops. But I believe that channel has gone silent. I believe they are currently using the Atlanta TRS for troopers in the metro area. I have no big desire to monitor (G)od's (S)pecial (P)eople really. All you'd probably hear is a lot of GCIC records checking....maybe the occasional DUI stop. Local cops are way more interesting to monitor.

Now that GSP works all interstate wrecks within the city of Atlanta its a very good talk group to listen to while driving, ive avoided major wrecks more than once doing this.
GSP actually has a lot of car chases, almost one a day. APD often times will call GSP while following a stolen car becuase they know it will turn into a chase as soon as a marked unit hits the blue lights.
At night the GSP nighthawks DUI task force is heavy in buckhead with DUI, foot chases, car chases.
Its really not a bad one to listen to.

 

[trooper890]

That's right. NYPD and LAPD are both UHF-T band conventional. Although LAPD is P25 digital. NYPD hasn't gone digital and most likely won't be. They've been using the same frequencies since the early 70s. It would be a logistical nightmare for the 5 boroughs to undergo that sort of transition. Mayor Bloomberg has also made it pretty clear that the City of New York is sick of getting ripped off by Motorola.

.

Yep, youre right.. but they are going to have to narrowband it in a short amount of time for an agency that size.. hundreds of reciever sites, repeaters, etc, plus additional sites to make up for the loss of coverage in 12.5k mode it's gonna be a whopping task and cost!!

 

[MTS2000des]

what loss of coverage is there in 12.5K mode? Plenty of conventional systems have gone narrowband with no loss of coverage or performance degradation. What systems are you referencing?

As far as the NYPD going narrowband, their communications director commented recently (IIRC an article was in UrgentComm) on the logistical nightmare the NYPD would face having to make ANY major overhauls to their system. As he said, the system works well (98 percent on hip in building coverage), is reliable, and is in use virtually 100 percent of the time. Any reduction of voice channels could impair officer safety, and even lead to serious issues if word got out that the police radios are "down" or having problems.

He suggested the overall cost to narrowband NYPD would be 150-300 million dollars when all is said and done, an astronomical cost that really is a waste of money to replace a working system with something that won't do anything more than it does today, and impair officer and public safety in the process, and cost the city a ton o' bucks they don't have only to replace the system in a few short years. He wants to hold out for 700MHz LTE and would rather spend the city money on the next generation of digital rather than squander it away. And I agree.

He wants to apply for a waiver for the NYPD to hold off on narrowband in 2013. That will be an interesting thing to watch come then, it's only 5 years away.

 

[b7spectra]

Don't forget, if, and when they go digital, you probably won't find their system listed under New York trunking, it will probably be listed as UASI!

 

[N_Jay]

what loss of coverage is there in 12.5K mode? Plenty of conventional systems have gone narrowband with no loss of coverage or performance degradation. What systems are you referencing?

Any FM system will operate with reduced S/N as the bandwidth is reduced.
Simple physics. No way around it.
It depends on the design of the original; system and the design of the replacement system as to whether the difference is critical to the operation.

As far as the NYPD going narrowband, their communications director commented recently (IIRC an article was in UrgentComm) on the logistical nightmare the NYPD would face having to make ANY major overhauls to their system. As he said, the system works well (98 percent on hip in building coverage), is reliable, and is in use virtually 100 percent of the time. Any reduction of voice channels could impair officer safety, and even lead to serious issues if word got out that the police radios are "down" or having problems.

He suggested the overall cost to narrowband NYPD would be 150-300 million dollars when all is said and done, an astronomical cost that really is a waste of money to replace a working system with something that won't do anything more than it does today, and impair officer and public safety in the process, and cost the city a ton o' bucks they don't have only to replace the system in a few short years. He wants to hold out for 700MHz LTE and would rather spend the city money on the next generation of digital rather than squander it away.

Much political posturing comes out in press releases and magazine articles.

He wants to apply for a waiver for the NYPD to hold off on narrowband in 2013. That will be an interesting thing to watch come then, it's only 5 years away.

Yes, it will be very interesting to watch.

 

[N_Jay]

Don't forget, if, and when they go digital, you probably won't find their system listed under New York trunking, it will probably be listed as UASI!

Does not seem likely, but you are the expert on the UASI systems.
http://www.fema.gov/government/grant/uasi/index.shtm

 

[pachanga22]

Any FM system will operate with reduced S/N as the bandwidth is reduced.
Simple physics. No way around it.

Have any experience with companding?

 

[N_Jay]

Have any experience with companding?

Yes, quite a lot.

It certainly makes the signal sound better but does not improve the basic S/N and adds no range at the threshold.

 

[MTS2000des]

Have any experience with companding?

Marietta, Ga's VHF LTR Passport system is narrowband and has just as much if not MORE coverage than the city's legacy wideband analog VHF system it used to use back in the 80's and 90's. SAME sites are used, so it isn't an issue of build out. They use a variety of Kenwood, Icom and Vertex Standard radios on the system. Users have ZERO complaints, and in fact, Marietta Fire (who also have Kenwood TK-7180 mobiles in all their fire engines) PREFER the sound quality and coverage of the new Passport system (used only by non-public safety city services at this time) over their new Astro 25 digital 800MHz radios on the Cobb DTRS (well, apparently some people insist on calling it "UASI" or "GEWIN") which suffer from many dead zones, poor audio quality, and in fact, most of MFD fireground communications take place on I-TAC conventional analog simplex due to the unpredictability of the P25 vocoder. Keep in mind, this system was implemented for less than the county spent on it's Smartzone 6 controller alone!

Paulding county has a VHF LTR narrowband system. No complaints there, the SO still uses wideband VHF as does the FD. No difference in coverage noted on that system.

Douglas county fire uses a VHF LTR narrowband as well. Again, compared to the SO which is still legacy wideband, no coverage or performance loss as N_Jay keeps asserting exists.

Blue Ridge PD uses a narrowband VHF in the worst terrain possible. Moved over from wideband about 4 years ago. No performance loss there. I know the system manager, maybe I'll get him to post here on his personal experience.


Seems like all the narrowband systems in GEORGIA (both trunked and conventional) are working just fine. No one complains like they do about these overpriced P25 systems getting forced upon us.

So N_Jay, what systems can you show us case studies on where a narrowbanding has taken place and performance degradation was observed? Please provide agency, systems or other data. Or is this another troll attempt at bashing something that you don't like so it "sucks" for everyone else?

 

[MTS2000des]

Yes, quite a lot.

It certainly makes the signal sound better but does not improve the basic S/N and adds no range at the threshold.

Again what systems in *GEORGIA* (since this is a GEORGIA forum), or anywhere in the USA can you provide specific examples of where this loss of performance and coverage due to narrowbanding happened other than your personal opinion, it doesn't seem to be a reality?

 

[N_Jay]

Darn, I forgot!

The laws of physics don't apply in Georgia.

Never mind!:roll::roll:

However, for those outside Georgia, where normal laws of physics apply, here are some references.
http://www.adcommeng.com/9_Narrowbanding.pdf Page 4

 

[MTS2000des]

Darn, I forgot!

The laws of physics don't apply in Georgia.

Never mind!:roll::roll:

However, for those outside Georgia, where normal laws of physics apply, here are some references.
http://www.adcommeng.com/9_Narrowbanding.pdf Page 4

so instead of trolling on a Georgia forum, how about answering the question. The so-called physics you posted have not proven true in all cases, in fact, have been quite the opposite on those systems here I named. I am sure others who are more familiar with the MTTA PassPort system can comment on it's coverage compared to the legacy wideband conventional system it replaced. It actually has about 30 percent MORE coverage than what it replaced according to the users I have spoken with. None of the systems named who recently narrowbanded their VHF analog systems have experienced the loss of coverage you claim is the "DANGER WILL ROBINSON" sign you have been peddling on RR, so I am curious what systems you are personally involved with that have? It seems that this is more hot air being blown up our butts by vendors, consultants and engineers who have a vested interest in selling us more costly, complex and profitable (for the vendors) digital systems, than merely reconfiguring existing current hardware to work on the narrow bandwidth.

I would love for you to post the call signs, locations and specifics on analog systems, trunked or conventional licensed in the USA below 512MHz, that are sucking wind since they narrowbanded. I'd love to see some links of media reports of these systems failing, and narrowbanding blamed for said failure.

I know you won't because it simply isn't the case. There isn't a "working group" to "solve the issues" of narrowband not working on the fireground like there is with P25 now is there? There aren't dozens and dozens of media reports of these newly narowbanded systems failing or having glitches that result in "close calls" like there have with P25. It is simply more HOT AIR.

Fact is all you can point to is more spin, brought to you by people who want to sell you NEW equipment, rather than help you maintain and improve what you have. Show me some real data on real systems or STFU.

and thanks again for proving how ignorant you are making comments about Georgians. We'll keep that in mind when you come and visit. "Ya'll come back now ya hear"

Here we go again...

I am sure you'll call the NYPD radio folks "damn yankees" because they aren't buying into your P25 bandwagon and are actually thinking forward and sensible by wanting to hold off for something really advanced like LTE versus pissing money away to replace a perfectly good system that serves it's users well every day in the second largest city in America. I know you got it all figured out.

The NYPD's problem is more logistic than anything, any change to the system is going to be a MAJOR undertaking, and not even your whiz-bang ASTROnomically priced P25 trunked system of the week can overcome the hurdles.

 

[N_Jay]

If all else is the same, you WILL have a reduction in coverage.
If you are not using the fringe are, you may not notice or be affected.
If you replace an old system with new equipment, you may also be making sufficient improvement to overcomes the loss. However you also may not.

You have a great tendency to take what is written, and misinterpret it outside what is written, and then argue with that misinterpretation.

There are a very large number of systems that today are working at the margin. To narrowband these systems blindly, without considering the loss of coverage is foolhardy.

 

[pachanga22]

Ok, I read the document. Still didn't explain the physics you keep referring to.

 

[N_Jay]

Ok, I read the document. Still didn't explain the physics you keep referring to.

For FM modulation, as the modulation index is reduced, (narrower modulated carrier for the same modulating signal) you will have a corresponding reduction in S/N.

I have been looking for a good link that summarizes a 3 credit upper level electrical engineering course on modulation theory in a simple web page to link to, but I am thinking that it probably does not exist. :wink::wink:

A very simplistic (but with errors) way to look at it is that a narrow band signal is like turning down the volume of the audio before transmitted, and turning up the volume at the receiving end. In very good coverage areas, you might not notice the difference, but as the signal gets weaker and the noise increases, you quickly get to the point where the noise has increased significantly, since when you turn down the volume of the transmitted audio you are reducing the desired signal, but when you turn up the volume at the receiving end, you are increasing both the desired signal AND the noise.

 

[MTS2000des]

If all else is the same, you WILL have a reduction in coverage.
If you are not using the fringe are, you may not notice or be affected.
If you replace an old system with new equipment, you may also be making sufficient improvement to overcomes the loss. However you also may not.

You have a great tendency to take what is written, and misinterpret it outside what is written, and then argue with that misinterpretation.

There are a very large number of systems that today are working at the margin. To narrowband these systems blindly, without considering the loss of coverage is foolhardy.

in typical snotty N_Jay style, you attempt to play the role of the puffed up cat and avoid the original question hoping that I'll just piss off and go away, but this is way too much fun!

so I'll ask it one more time and maybe your 200 plus IQ and close to 8600 plus posts in 5 years (gee must have lots of time on your hands) can explain it to us simpletons:

provide the call signs of systems experiencing loss of RF coverage due to narrowbanding their radio systems below 512MHz.

I'll do my part and contact them and see what they say. but the silence is deafening, no matter what bandwidth or mode it's being modulated with....

 

[N_Jay]

in typical snotty N_Jay style, you attempt to play the role of the puffed up cat and avoid the original question hoping that I'll just piss off and go away, but this is way too much fun!

In your typical style, you exaggerate others points to give yourself a platform to argue from.
I am glad you are having fun. It is nice to see someone who can have such fun making a fool of themselves.

so I'll ask it one more time and maybe your 200 plus IQ and close to 8600 plus posts in 5 years (gee must have lots of time on your hands) can explain it to us simpletons:.

I think I just did. Maybe if you read it carefully you would either understand or be able to form a concise question.

provide the call signs of systems experiencing loss of RF coverage due to narrowbanding their radio systems below 512MHz..

Sorry, not playing into your tit-for-tat discussion.
If you want to say categorically there is no reduction, then you are arguing against my assertions. If you are not, then you are just arguing for the sake of arguing.

I'll do my part and contact them and see what they say. but the silence is deafening, no matter what bandwidth or mode it's being modulated with....

Sorry, my job is to prevent these problem, not keep a log of them, but thanks for playing.