What good is commercial digital two-way anyway?
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What good is commercial digital two-way anyway?
I understand using digital formats on ham radio and satellite (both broadcast and uplink/downlink), and perhaps using digital two-way in a situation like taxicab dispatch, but what about in in a public safety situation where the latency of a digital codec could make a half a second's difference between life and death for a firefighter in a burning building or a cop in a shootout?
(I'm also opposed to digital terrestrial broadcasting, as I think the installed base of analog equipment is so large that IBOC and DRM represent bad investments. DAB I'm undecided on -- it makes some sense for value-added services like BBC 6Music -- but the possibility of eliminating analog terrestrial radio altogether just seems like a bad idea for economic reasons.)
(I'm also opposed to digital terrestrial broadcasting, as I think the installed base of analog equipment is so large that IBOC and DRM represent bad investments. DAB I'm undecided on -- it makes some sense for value-added services like BBC 6Music -- but the possibility of eliminating analog terrestrial radio altogether just seems like a bad idea for economic reasons.)
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if it boils down to half a second, you were going to die anyway.
Police, Firefighters and EMS are the most collectively dysfunctional group of people in existence and only we understand each other!
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I used to have the viewpoint of "Digital doesn't belong in a public safety system". That is, until I had a decent system by which to judge. Here in Ontario, we have a VHF SmartZone system with both analog and ASTRO talkgroups. The audio quality on digital isn't bad at all. It's DIFFERENT, but different does NOT mean bad.
In reality, is half a second REALLY going to make a difference? Maybe on paper, but in reality half a second isn't going to make a difference - like the other guy said, if it comes down to half a second, you're probably already dead anyway.
Why digital? How about better quality, better range, more features, easier encryption...the list goes on and on.
-Mike
In reality, is half a second REALLY going to make a difference? Maybe on paper, but in reality half a second isn't going to make a difference - like the other guy said, if it comes down to half a second, you're probably already dead anyway.
Why digital? How about better quality, better range, more features, easier encryption...the list goes on and on.
-Mike
Tim, et al,
The primary driver is the need (now federal mandate) for spectrum efficiency.
A legacy wide voice FM channel in the Part 90 space is replaced by 2 narrowband channels. Narrowband analog FM voice (11K0F3E) has acceptable Q of S especially when companded, but still doesn't have the *punch* of wide analog FM voice.
The perceptual coding advances in recent years now give high MOS (mean opinion score) results for the current genration of IMBE and AMBE vocoders. A 2.4 kbs voice channel and an interleaved data channel may be simultaneously transmitted as one composite signal and result in more available channels.
Another primary driver for digital voice in public safety systems is the perceived need for encryption. Digital voice is easily encrypted and provides much better voice quality then the legacy CVSD DES encryption. Analog scrambling is thwarted by a determined listener after time in most cases.
Perceptual coders greatly suppress road/wind noise and if properly implemented may offer slightly increased range over analog voice.
The *real* driver may be radio system manufacturers :fool:
Out there in the "Pine Curtain" I think that I might want to see if DV was effective. I know that Nacogdoches PD switched to P25 after the Shuttle Recovery, has there been any comments by the NPD on their Q of S with their P25 system?
kv5e
The primary driver is the need (now federal mandate) for spectrum efficiency.
A legacy wide voice FM channel in the Part 90 space is replaced by 2 narrowband channels. Narrowband analog FM voice (11K0F3E) has acceptable Q of S especially when companded, but still doesn't have the *punch* of wide analog FM voice.
The perceptual coding advances in recent years now give high MOS (mean opinion score) results for the current genration of IMBE and AMBE vocoders. A 2.4 kbs voice channel and an interleaved data channel may be simultaneously transmitted as one composite signal and result in more available channels.
Another primary driver for digital voice in public safety systems is the perceived need for encryption. Digital voice is easily encrypted and provides much better voice quality then the legacy CVSD DES encryption. Analog scrambling is thwarted by a determined listener after time in most cases.
Perceptual coders greatly suppress road/wind noise and if properly implemented may offer slightly increased range over analog voice.
The *real* driver may be radio system manufacturers :fool:
Out there in the "Pine Curtain" I think that I might want to see if DV was effective. I know that Nacogdoches PD switched to P25 after the Shuttle Recovery, has there been any comments by the NPD on their Q of S with their P25 system?
kv5e
WILSON WILSON, GREEN, WE HAVE RAWHIDE ARRIVAL, NO PRESS, NO PROTESTORS
OPP runs a vhf p25 system that sounds great (from what i heard)
and I've heard nothign but good things about rcmp's 800 p25 system.
and I've heard nothign but good things about rcmp's 800 p25 system.
N3JFW 4:29 pm
(4:29:48 PM): so he's gay huh
(nameless ham) 4:30 pm
(4:30:02 PM): haha no, but he is a music major
N3JFW 4:30 pm
(4:30:15 PM): so he's still in the closet
(4:29:48 PM): so he's gay huh
(nameless ham) 4:30 pm
(4:30:02 PM): haha no, but he is a music major
N3JFW 4:30 pm
(4:30:15 PM): so he's still in the closet
Re: What good is commercial digital two-way anyway?
Okay, all fair answers. Thank you.
The audio is better, less jammers and interference but the computer/data terminal portion of it still has some bugs to get worked out.kv5e wrote: Out there in the "Pine Curtain" I think that I might want to see if DV was effective. I know that Nacogdoches PD switched to P25 after the Shuttle Recovery, has there been any comments by the NPD on their Q of S with their P25 system?
kv5e
That is, until, cheap P25 radios hit the market. I remember back when Trunking was just becoming popular, nobody had trunking radios because they were so cheap. Now some 10 years later (maybe more?) you can buy trunking radios on ebay for 50 dollars. Heck, I picked up two 800MHz trunking radios for 25 dollars (for the pair). Eventually you'll see digital radios go that cheap.kd5ing wrote:...less jammers
-M
They have their system set up to where each radio has an id associated with it. Without an assigned ID, the repeater will not key nor will the radios pick up the unblessed transmitter on simplex.exkalibur wrote:That is, until, cheap P25 radios hit the market. I remember back when Trunking was just becoming popular, nobody had trunking radios because they were so cheap. Now some 10 years later (maybe more?) you can buy trunking radios on ebay for 50 dollars. Heck, I picked up two 800MHz trunking radios for 25 dollars (for the pair). Eventually you'll see digital radios go that cheap.kd5ing wrote:...less jammers
-M
Plus, when you keydown one of the radios, the transmitter id is recorded into the record.
They know who you are.
:whiner:n3jfw wrote:please stay on topic
Forum for the promotion and understanding of digital voice on the amateur bands.
Sorry, Fred. :OSS:
On topic (before you can my ass)... has anyone tried those Bendix King P25 front-panel programable portable?
Last edited by KC8RYW on Tue Mar 01, 2005 3:41 pm, edited 1 time in total.
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n3jfw wrote:OPP runs a vhf p25 system that sounds great (from what i heard)
and I've heard nothign but good things about rcmp's 800 p25 system.
The RCMP's 800 Astro system in Nova Scotia is the best, excellant audio, excellant coverage (68 repeaters in 2 different provinces) the system has never gave them any trouble
right now they are in the process of setting up a conventional 800 MHz astro repeater network so they can use failsoft on their XTS3k's incase something goes wrong with the trunk
Nick
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yes, I have. A vendor brought a couple DPH radios, one channel was set to analog and the other channel set to digital. I went outside and we switched back and forth. At first, there is no difference in audio quality but careful listening it seems the analog mode had slightly better fidelity (but not really anything significant unless you audiophile or want to transmit music). Also, the DPH is now continous from 136 to 174 (no split). it is fully narrowband NTIA compliant.KC8RYW wrote:On topic (before you can my ass)... has anyone tried those Bendix King P25 front-panel programable portable?
What is neat about the DPH is it is the same as the LPH/EPH/GPH (exception apco25 and alpha), that is, uses the same batteries and accessories and operated exactly like previous BK models. Vendor let me program in a freq but he did not have a programming plug. I shorted the two contacts in the mic socket, pressed FCN, entered the 6 zeros and in the program mode just like a LPH.
One of the features I tried was the DPH mixed mode. If you don't know if a channel is analog or digital, set it to mixed mode and the radio will sense the mode to use. If you transmit within a few seconds, it will transmit in the appropriate mode. The test I did was a local sheriff channel that is APCO25 (I set to receive only! zeros were in the transmit field) and selected mixed mode. The audio was somewhat warbly when first receiving a signal but then it later sounded fine.
If you are a federal agency, you can buy them at $1100 each. I'd like to get a DPH for my personal use but too pricey for me at this time. Would also be a great scanner (I use BK handhelds and mobiles as scanners for good audio, noise rejection, hamsexy factor, etc).
Speaking of APCO25, I asked a Icom vendor why D-star instead of APCO25. He said all APCO25 radios have to pay a royalty to Motorola, but a Motorola guy said that is false. APCO25 is a standard (the moto guy asked, "did a M/A-COM guy say that?"). I also heard APCO25 not only specifys digital voice, it also specifys electrical and mechanical properties of a radio.
Mike
Got any clue what us normal people could buy a DPH for? $1100 is pretty cheap!
APCO25 is a standard - no royalties. *BUT*, APCO25 specifies the IMBE (improved multiband excitation) audio codec, which is owned by DVSI (Digital Voice Systems Inc.) You do have to pay royalties to them.
Of course, Icom is using AMBE2020 (advanced multi-band excitation), also owned by DVSI, also requiring royalties.
Icom is pushing DSTAR here because, as I understand it, Japanese public safety is already using the system (the firmware has been crippled to remove encryption capabilities, etc.) and they can simply cripple the firmware and ship it over here rather than having to play with a different standard. My guess is they also want to draw a "line in the sand" between the commercial and hammy worlds.
APCO25 is a standard - no royalties. *BUT*, APCO25 specifies the IMBE (improved multiband excitation) audio codec, which is owned by DVSI (Digital Voice Systems Inc.) You do have to pay royalties to them.
Of course, Icom is using AMBE2020 (advanced multi-band excitation), also owned by DVSI, also requiring royalties.
Icom is pushing DSTAR here because, as I understand it, Japanese public safety is already using the system (the firmware has been crippled to remove encryption capabilities, etc.) and they can simply cripple the firmware and ship it over here rather than having to play with a different standard. My guess is they also want to draw a "line in the sand" between the commercial and hammy worlds.
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I believe they do have to pay /\/\ for certain patents related to P25 trunking, but not for conventional mode. I could be wrong, though.Michael Wright wrote:Speaking of APCO25, I asked a Icom vendor why D-star instead of APCO25. He said all APCO25 radios have to pay a royalty to Motorola, but a Motorola guy said that is false. APCO25 is a standard (the moto guy asked, "did a M/A-COM guy say that?"). I also heard APCO25 not only specifys digital voice, it also specifys electrical and mechanical properties of a radio.
Mike
You know how many hams run a trunking system...mr.syntrx wrote:I believe they do have to pay /\/\ for certain patents related to P25 trunking, but not for conventional mode. I could be wrong, though.Michael Wright wrote:Speaking of APCO25, I asked a Icom vendor why D-star instead of APCO25. He said all APCO25 radios have to pay a royalty to Motorola, but a Motorola guy said that is false. APCO25 is a standard (the moto guy asked, "did a M/A-COM guy say that?"). I also heard APCO25 not only specifys digital voice, it also specifys electrical and mechanical properties of a radio.
Mike
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actually there is a ham working on a 2m trunked radio system! Someplace here on hamsexy or on the new batlounge. It looks like a real interesting project, lotsa experimentation. He does admit his TRS is one of the most complicated unreliable trunked systems around but it's a start. He sometimes gets complaints from hammies... but that's another thread.KC8RYW wrote:You know how many hams run a trunking system...
Anyway, regarding digital formats, I have this feeling business band/public safety gear and VHF/UHF amateur gear is becoming more dissimilar. LMR guys are going P25 and narrowband. Although they are different groups of animals. All the radio guys at IWCE Las Vegas don't carry radios with them, a very small number of cars in the lots have mobile radio antennas.
Well, I will not be at Dayton but if I was, the first stop I'd make is at the hamsexy booth just to see how people react to it.
Mike
what format trunking is he using?Michael Wright wrote:actually there is a ham working on a 2m trunked radio system! Someplace here on hamsexy or on the new batlounge. It looks like a real interesting project, lotsa experimentation. He does admit his TRS is one of the most complicated unreliable trunked systems around but it's a start. He sometimes gets complaints from hammies... but that's another thread.KC8RYW wrote:You know how many hams run a trunking system...
Anyway, regarding digital formats, I have this feeling business band/public safety gear and VHF/UHF amateur gear is becoming more dissimilar. LMR guys are going P25 and narrowband. Although they are different groups of animals. All the radio guys at IWCE Las Vegas don't carry radios with them, a very small number of cars in the lots have mobile radio antennas.
Well, I will not be at Dayton but if I was, the first stop I'd make is at the hamsexy booth just to see how people react to it.
Mike
Well, a few problems here & there, but yes, overall a fantastic system giving 85% portable landmass coverage in Nova Scotia, about 95% with mobiles. Blows everything else (cellular, paging, the old VHF provincial system, etc) out of the water.VE9MP wrote: The RCMP's 800 Astro system in Nova Scotia is the best, excellant audio, excellant coverage (68 repeaters in 2 different provinces) the system has never gave them any trouble
Todd
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wavetar wrote:Well, a few problems here & there, but yes, overall a fantastic system giving 85% portable landmass coverage in Nova Scotia, about 95% with mobiles. Blows everything else (cellular, paging, the old VHF provincial system, etc) out of the water.VE9MP wrote: The RCMP's 800 Astro system in Nova Scotia is the best, excellant audio, excellant coverage (68 repeaters in 2 different provinces) the system has never gave them any trouble
Todd
Hey, I think we're up to 69 sites now, apparently one went up in Chaswood area somewheres near Shubie
I was doin some listening today....and it made me get all excited
heh....I heard CFB Gagetown MP's using ASTRO on 57920 (E24) I thaught they were all on VHF. Guess i'm gonna have to go down and have a looksie at some of their radios
![THE BABY! :baby:](./images/smilies/smileybaby.gif)
Ever hear of any plans to expand the system beyond Fredericton, Todd?
Nick
The New Brunswick government is having trouble seeing the forest for the trees. They have so far been very resistant to having government departments commiting to switch over to the TMR system. This of course is necessary in order for Aliant to consider expanding the infrastructure into New Brunswick, otherwise it's just not economically feasible for them to do so.VE9MP wrote:
Hey, I think we're up to 69 sites now, apparently one went up in Chaswood area somewheres near Shubie
I was doin some listening today....and it made me get all excited
heh....I heard CFB Gagetown MP's using ASTRO on 57920 (E24) I thaught they were all on VHF. Guess i'm gonna have to go down and have a looksie at some of their radios![]()
Ever hear of any plans to expand the system beyond Fredericton, Todd?
I'm surprised the RCMP haven't been able to get things rolling in NB, considering they were one of the driving forces behind the system in NS, and they seem to be extremely happy with it.
Having seamless coverage throughout the Atlantic Provinces would be ideal...but the last I heard was the NB government was considering putting in a TAIT province-wide VHF system!! Talk about ass-backwards. qrzmoderator
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Chesus christ
Tait? vomit
Thats why they've been replacing all the old midlands with Tait TM2000ii's qrzmoderator
Someone told me that Aliant had plans to go beyond Fredericton and that they had the plans all drawn up and everything, it was just the $$$ factor.
Simply put, New Brunswick is fucked up.
All decisions in regards to communications are left up to people who know didily-effing-squat about communications. The RCMP have known problems with their system, repeaters go down (a lot), members are left with simplex or cell phones, quite unacceptable, IMO.
Fisheries and Oceans made the switch to TMR last summer I think in Southern NB, and they've been quite pleased, they have ASTRO DES-XL on the TMR and a bunch of stand alone encrypted repeaters a long the coast.
:whiner:
I swear, if they put up a Tait system, i'm going down to EMO and i'll start slapping everyone I know in the face with my Saber :OSS:
Hell, it couldn't cost that much to add another zone or two to an already established network then compared to putting up an entire new network.
....and yes, seamless coverage in the Maritimes would kick ass! Now if only you didn't have to affiliate.
![ass rape :anus:](./images/smilies/icon_eek.gif)
Tait? vomit
Thats why they've been replacing all the old midlands with Tait TM2000ii's qrzmoderator
Someone told me that Aliant had plans to go beyond Fredericton and that they had the plans all drawn up and everything, it was just the $$$ factor.
Simply put, New Brunswick is fucked up.
All decisions in regards to communications are left up to people who know didily-effing-squat about communications. The RCMP have known problems with their system, repeaters go down (a lot), members are left with simplex or cell phones, quite unacceptable, IMO.
Fisheries and Oceans made the switch to TMR last summer I think in Southern NB, and they've been quite pleased, they have ASTRO DES-XL on the TMR and a bunch of stand alone encrypted repeaters a long the coast.
:whiner:
I swear, if they put up a Tait system, i'm going down to EMO and i'll start slapping everyone I know in the face with my Saber :OSS:
Hell, it couldn't cost that much to add another zone or two to an already established network then compared to putting up an entire new network.
....and yes, seamless coverage in the Maritimes would kick ass! Now if only you didn't have to affiliate.
Nick
Not so much a slam against TAIT intended, more so to the NB government for not wanting to take advantage of an already exisiting SmartZone Omnilink system which merely has to be expanded into the province, not built from the ground up. It was proven here in NS that if properly engineered & implemented, Motorola's system kicks serious ass. Hell, a lot of Southern NB is covered by it, and it's not even intentional.mr.syntrx wrote:Nothing wrong with Tait equipment. They're kicking Motorola's arses from wall to wall in this great brown land.
MPT-1327 is gay compared to Smartzone or P25, though.
Yes, I originally programmed all of their radios, and was in St.John to give a 1-day crash course on the radios & TMR system in general. DFO is loving it.VE9MP wrote: Fisheries and Oceans made the switch to TMR last summer I think in Southern NB, and they've been quite pleased, they have ASTRO DES-XL on the TMR and a bunch of stand alone encrypted repeaters a long the coast.
Gagetown huh? Makes sense since all of DND here in Halifax have been on the system since about April of last year. CFB Greenwood was a couple of years earlier. I also programmed their radios as well. A small number of older XTS3000, but the bulk are XTS2500 & XTS5000 for portables, with Astro Spectras for mobiles. I didn't do any specifically for Gagetown though...you might have only heard some of the visiting MP's from NS or something.VE9MP wrote: heh....I heard CFB Gagetown MP's using ASTRO on 57920 (E24) I thaught they were all on VHF. Guess i'm gonna have to go down and have a looksie at some of their radios![]()
Todd
Ashton Kutcher gave up his Playstation 2...I guess I would too if I had Bruce Willis' eX-box...