Standard vs Narrow Systems

[loumaag]

A question for the EDACS system knowledgeable.

Other than the obvious difference in bandwidth between the systems, does the EDACS Standard (Wide) system have any advantage (subscriber or system) over the Narrow systems. The question comes from the effort seen sometimes to use the 9600 baud standard CCh on a narrow-band frequency allocation. It just doesn't make sense to shoe horn that wide CCh in a band pass that it doesn't really fit in unless there is something different from the system standpoint.

 

[SCPD]

The extra bandwidth on the control channel makes for a more responsive system.

68 codewords per second on 9600 baud vs. 34 codewords per second on 4800 baud.

On small systems it won't make much of a difference but on networked sites with close to the maximum number of channels you can reach a point where late-entry continuation messages fill nearly all available codeword slots leaving no room for other essential messages. Some messages like rejects, busies, logons, and grants need to be issued in a timely manner. You'll also want some extra headroom for less urgent messages like station identity, neighbor announcements, and patches.

 

[loumaag]

Thanks Rick, yeah I kind of figured that you can jam more info in the wider bandwidth but I was more wondering if the software supported other factors for the Wide that were not available in the Narrow, like APCO-16 support.

The question came up in a round-about way when a RR user made a comment about this new system. Doesn't look to have networking issues, etc. But I was wondering about safety concerns; just trying to get a handle on it is all.

 

[SCPD]

I was more wondering if the software supported other factors for the Wide that were not available in the Narrow, like APCO-16 support.

The only thing I have NOT seen on a narrow band system vs. standard is ProVoice.

 

[loumaag]

The only thing I have NOT seen on a narrow band system vs. standard is ProVoice.

Ahhh. I didn't even think of that.

 

[WCRadioGuy]

The only thing I have NOT seen on a narrow band system vs. standard is ProVoice.

ProVoice works great on a narrow band VHF system. I maintain a VHF narrow band and have used ProVoice with ni problems.

 

[loumaag]

ProVoice works great on a narrow band VHF system. I maintain a VHF narrow band and have used ProVoice with ni problems.

This is a 4800 baud CCh system, or a 9600 baud CCh on a super-narrow band allocation?

 

[SCPD]

ProVoice works great on a narrow band VHF system. I maintain a VHF narrow band and have used ProVoice with no problems.

Hi WC. My understanding is the voice channels running ProVoice must operate at 9600 baud. There's no way to squeeze ProVoice into a 4800 bit per second pipe. If the voice channels can run at 9600 baud, there's no point in constraining the control channel to 4800.

I'll echo Lou's question. Is the control channel on your system 4800 or 9600 baud?

 

[DaveH]

Interesting. I read the book on EDACS about 15 years ago but don't
recall all the details I'd like to (and the manual was on loan). NB systems
could do NB analog voice, 4.8k data, and the digital voice I'm not certain.
Not sure if ProVoice existed at the time.

I believe there's a NB 900MHz system in Toronto with ProVoice although
I recall comments that it sounded terrible. Database says it's Standard
i.e. Wide, but Industry Canada TAFL search shows 11kHz BW i.e. Narrow.
I thought all 900MHz systems in Canada were NB like the US. Emission
Type doesn't show digital, so maybe it's a different system. Someone
from the GTA could confirm that.

Dave

 

[loumaag]

Dave,

Yes, we have the LCRA system here in TX that is 900 MHz narrow band but using a Standard CCh. It does not use ProVoice but it is a widely spread network with a mix of public safety and public utility users. It's use by public safety and the trouble with squeezing that CCh into the narrow band allocation is one of the reasons I was seeking additional info.

 

[SCPD]

For the database we use the terms "Standard" and "Narrow" to indicate the baud rate as 9600 or 4800. The actual licensed bandwidth may vary.

From a third party - WCRadioGuy's four channel VHF system is 9600 baud.

Lou - the LCRA system carries voice and data. The data (like the control channel) is 9600 baud.

-rick

 

[WCRadioGuy]

For the database we use the terms "Standard" and "Narrow" to indicate the baud rate as 9600 or 4800. The actual licensed bandwidth may vary.

From a third party - WCRadioGuy's four channel VHF system is 9600 baud.

Lou - the LCRA system carries voice and data. The data (like the control channel) is 9600 baud.

-rick

Yes, it is a 9600 baud, but it is 5 channel, not that that makes a big difference. Who's the 3rd party?

 

[SCPD]

Who's the 3rd party?

One of the RR DB administrators - AudioDave1 - was able to pick up the control channel from a distance earlier this month (skip?). Only four channels (LCN 1 through 4) were in rotation at the time (August 10th).

 

[WCRadioGuy]

One of the RR DB administrators - AudioDave1 - was able to pick up the control channel from a distance earlier this month (skip?). Only four channels (LCN 1 through 4) were in rotation at the time (August 10th).

Oh ok. That must have been Site 2. The system is a 2 Site system. Site 2 has 5 channels but the 5th has not been licensed yet.