Kern County Fire narrow band change starts

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Eng74

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I also put this up in the updates section.
Here is an update for Kern County Fire. They are starting the change over to narrow band. Kern 1 153.7850 PL 167.9
Kern 2 155.8800 PL 167.9
TAC 4C 159.4725 PL 167.9
Tac 5C 154.4525 PL 167.9
 

1979lee

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Eng74, thanks for the update, i wondered what was going on,
with fire dispatch on kern 1 & 2,
Here's a fool question, what is narrow band, i should know this , with me being a ham too

ki6mxl
 

Eng74

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I am not up on all the whys but I want to say the Feds have already made the switch to narrow band, It could just be our version of the 800 rebanding? Kern 1 and Kern 2 will be linked for the month of April. This will be a 3 year project and this is the first phase.
 

SCPD

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In "narrow band" the signal occupies no more than 6.25 kHz on each side of the center frequency or a total of 12.5 kHz of bandwidth. This is half of the bandwidth the older 25 kHz signals occupied. In doing so 80 communications channels exist in every 1 MHz of bandwidth instead of the old 40. All new equipment is required for this change as the radio must transmit all of the information over a much narrower range of frequency. With the RF spectrum becoming crowded, doubling its capacity will allow for more efficient use of the spectrum and expansion of many radio systems.

This change is being made to the lower end of the UHF band and the VHF band only. Channel spacing for frequencies 470 MHz and up was already at 12.5 kHz. The so called UHF-T band, which was allocated in many large cities some 30 years ago using UHF TV channels 14-20 or 470-512 MHz, and the 800-900 MHz band were assigned from their inception at the narrower spacing.

Another development is the requirement for all TV broadcasting to be digital by next February, which will allow more TV channels to be broadcast in the same amount of bandwidth. At the same time TV stations at the upper end of the UHF TV allocations are being moved to lower frequencies, allowing the allocation of the new 700 MHz band to public safety and other users.

Narrowbanding and digital TV have the goal of squeezing more use out of the same fixed amount of radio frequency resource. Many areas in the country, mostly the major metro areas, that span many counties, had run out of radio frequency spectrum and some type of relieve was necessary.

Confused? Here is an example of the old spacing in the federal VHF band:

168.125, 168.150, 168.175, 168.200, 168.225, 168. 250 etc. which are spaced .025 MHz or 25 kHz apart.

The new narrow band spacing adds frequencies in between at .0125 MHz or 12.5 kHz apart and using our example above it would look like this:

168.1250, 168.1375, 168.1500, 168.1625, 168.1750, 168.1875, 168.200, 168..2125, 168.2250, 168.2375, etc.

Because FM is frequency modulation (Duh!) it modulates the signal by varying the frequency. Narrower signals must carry the same amount of information over a smaller range of frequencies so it is received at a lower volume on a scanner. The mix between narrow band and "wide band" radio reception is problematic with an older scanner, as the narrow band is so quiet the volume must be turned up to hear it. When the next reception involves an older "wide band" radio this same volume setting can blast you out of your seat. The new GRE-500 and 600 radios can be programmed to add an "audio boost" on the newer narrow band frequencies and the signals from a mix of narrow and wide band frequencies are now nearly equal at the same volume setting. This will become more important from now until 2013 when all public safety is required to transmit in narrow band, as there will increasingly be a mixture of narrow and wide band signals in every day listening.

Kern County happens to be on the leading edge of state and local agencies switching to narrow band. CDF began the process with the addition of two narrow band frequencies at 151 MHz for two new air to air tactics channels. All of the so called "federal interoperability" VHF channels were allocated in narrow band and these frequencies will see increased usage on incidents involving a mixture of federal, state, and local agency resources as more and more state and local agencies obtain narrow band radios. These frequencies are cleared for nationwide use and such frequencies are very much in short supply using existing "wide band" radios.

Bottom line, get used to narrow band, it is the future!
 

SCPD

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Eng74 said:
I am not up on all the whys but I want to say the Feds have already made the switch to narrow band, It could just be our version of the 800 re-banding? Kern 1 and Kern 2 will be linked for the month of April. This will be a 3 year project and this is the first phase.
Narrow banding and re-banding are two different issues and should not be confused. I've explained narrow banding. Re-banding is being done because Nextel established their cell phone network using 800 MHz frequencies outside the normal cell phone allocations by using a unclarity in the regulations that the FCC established for SMR systems or "Specialized Mobile Radio." By doing so they created unacceptable interference to thousands of public safety radio systems all over the U.S. These SMR frequencies were sandwiched in with public safety frequencies. Re-banding involves moving Nextel's frequencies and public safety frequencies apart to get rid of the "sandwiching." Nextel is footing the bill for all of it so many public safety systems are not only going to be using new frequencies, they will be using new hardware as well.
 

1979lee

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Again Exsmokey, your replies are brilliant!!! thanks!!!

also kern fire ch kern 1 , is that now on 153.785? or is k1 still 155.880?
another thing, is the kern sheriffs dept changing anything on there radio setup?


thnaks

ki6mxl
 

Eng74

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Kern 1 is 153.7850 and Kern 2 is 155.8800. As far as I know there will be no changes to the SO radio plan. By reading Exsmokey's post there will not be. Thanks for the info my neighbor to the north. Watch out I know two guys who are going to be Inyo Couty SO's. One will be out on the streets in another month, the other just started his academy. There will not be a doughnut in the county!
 
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Kern 1 and Kern 2 are patched while the radio techs flip the 2 channels. Kern 1 (155.880) will become Kern 2, and Kern 2 (153.785) will become Kern 1. This IS NOT being done to switch to narrowband, it is being done due to intermod in the system. Both channels will be patched for the next month or so, till the radio techs can get out to reprogram all fire radios on the system. The only channel Kern County has that is Narrowband is the UHF Mutual-Aid channel 453.225 which is 12.5 khz. Kern County will not be going narrowband till at least 2012 when they are planning a replacement for the current system. We are also looking at going digital with the new systems, both UHF & VHF.
 

1979lee

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dmd911dispatcher
thanks for the heads up, ugg digital, i heard talk around here back in 05 about trunking,
and the old canyon red 453.225, i thought it was abandoned, as i havent heard anything on it for quite sometime now.
there is some terrible (intermod) on kern 2 154.860, when someone talks on it , it messes up kern 1 something fierce, kern 3 155.625, thats a whole different story, it sounds clear at times the bamm some other agency walks all over the comm trafic

ki6mxl
 

Eng74

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As long as it took to get KCFD over to VHF and the way the state's budget is I would bet that a new radio system will not happen by 2012. The intermode has been with Kern 1 and Kern 4. When Bat's 3 or 6 go to Kern 4 it makes Kern 1 bad until they can get everyone on the Tac channel.
 

SCPD

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I think there is some confusion because dmd stated that the only narrowband frequency being used in Kern County is a UHF one. Tacs 4C and 5C are 12.5 kHz center frequencies so that certainly creates the impression that narrow band is being used. Is there another explanation?
 

Eng74

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Well I don't know who dmd911dispatcher is, but I'll take the Batt Chief's word that is in charge of radios for KCFD since he is the one who sent the radio plan and changes out to all the stations.
 

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Arriving somewhere, but not here . . .
As "keeper" of the frequency lists for my Department (not to be confused with somebody who makes policy - lots of paygrade difference between that person and me!), I need to confirm whether or not KRN is going narrowband or not, and for what channels. I am with Eng74 in that the BC who is in charge of the project should know, but all to often the BC's THINK they know something, but in reality the techs are talking about something altogether different.

Also, for the short trem, the only changes I need to worry 'bout for the next week or so (traveling to Sac. on personal business) is that KRN 1 and KRN 2 are patched, but not Narrowbanded (yet?). Is that correct?

So, anybody know for sure?
 

ScannerDude244

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Exsmokey said:
Narrow banding and re-banding are two different issues and should not be confused. I've explained narrow banding. Re-banding is being done because Nextel established their cell phone network using 800 MHz frequencies outside the normal cell phone allocations by using a unclarity in the regulations that the FCC established for SMR systems or "Specialized Mobile Radio." By doing so they created unacceptable interference to thousands of public safety radio systems all over the U.S. These SMR frequencies were sandwiched in with public safety frequencies. Re-banding involves moving Nextel's frequencies and public safety frequencies apart to get rid of the "sandwiching." Nextel is footing the bill for all of it so many public safety systems are not only going to be using new frequencies, they will be using new hardware as well.
Sprint is moving away from Iden they have been working with Qualcomm chip maker to make qchat Push-to-Talk. It's just as fast Motorola iden Push-to-Talk, but over EV-DO high speed. They wanna scarp Nextel's network it's just a pain for public safety and them.

Check out the demo iDen Vs qChat

http://youtube.com/watch?v=An_FIV4PCFI
 
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Hi MCIAD .. I go back to work tomorrow .. been on my weekend and will double check with the radio techs, but from what they told me last week, the only change is flip-flopping Kern-1 and Kern-2, but they both are patched for the next month or so. Unless something changed since I talked to the county radio techs last week, none of the VHF channels are going narrow band. When the new system was put in, there was talk of narrow band tac channels for the fire department, but the radios the that were bought would not support narrow band. That information is from one of the radio techs in charge of the county radio shop.

As for ENG74 wondering who I am, I'm a dispatcher for the sheriff's department, and a radio geek who is always in the shop talking about the county systems with the radio techs.
 

zerg901

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1. Over on the PrivateWirelessForum at Yahoogroups.com, everyone is trying to figure out if narrowband FM (11K2F3E) has shorter range than normal FM (20K0F3E).

2. Some folks think that the FCC channel seperation requirements are far too conservative. (I think that NTIA or DOD did a study on this).

3. IIRC San Diego Fire found that their voice traffic dropped by 70% when they installed mobile data terminals.

Add this all up - what do you get? I dont know. Maybe Kern County Fire should go to narrowband - maybe they shouldn't.

Peter Sz
 

SCPD

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ScannerDude244 said:
Sprint is moving away from Iden they have been working with Qualcomm chip maker to make qchat Push-to-Talk. It's just as fast Motorola iden Push-to-Talk, but over EV-DO high speed. They wanna scarp Nextel's network it's just a pain for public safety and them.

Check out the demo iDen Vs qChat

http://youtube.com/watch?v=An_FIV4PCFI
Are you saying that the need for rebanding is going to disappear? If so that is big news!
 

SCPD

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zerg901 said:
1. Over on the PrivateWirelessForum at Yahoogroups.com, everyone is trying to figure out if narrowband FM (11K2F3E) has shorter range than normal FM (20K0F3E).

2. Some folks think that the FCC channel seperation requirements are far too conservative. (I think that NTIA or DOD did a study on this).

3. IIRC San Diego Fire found that their voice traffic dropped by 70% when they installed mobile data terminals.

Add this all up - what do you get? I dont know. Maybe Kern County Fire should go to narrowband - maybe they shouldn't.

Peter Sz
I think it is much harder to pick up narrow band signals than the older 20 kHz signals based on my experience monitoring federal systems for the last three years. I've heard remarks being made over the air by federal employees saying the same. A retired Forest Service radio tech told me some years ago that the Mendocino National Forest, the first Forest to go narrow band in California, had to install additional repeaters after the switch. They made the change before the 1/2005 deadline.

The fact that traffic falls off after MDT's are installed isn't surprising, but I'm wondering if it will stay that way. Could it be the MDT's being new that has everyone playing with them and when that wears off, voice traffic will again pick up some? I don't mind hearing less of the incredibly boring 10-28 traffic droning on and on anyway.

The need for voice traffic will continue, especially for on-going incidents using tactical frequencies and channels. Having plenty of tactical channels has always been a concern. System designers obviously can't design the church for Easter Sunday, or in other words for the biggest scenario that anyone can think up, however, the number of tactical channels is still too low in many jurisdictions. The federal government is creating new command and tactical frequencies due to narrow banding. Many BLM, National Park Service, and U.S. Forest Service units have installed up additional nets, such as an admin net to supplement Forest Net, because of the additional frequency availability resulting from narrow banding.

I don't foresee the FCC backing off the requirement to go narrow band by 2013 anymore than I saw them backing off the requirement for digital TV many years ago.
 
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