Wideband ro Narrow Band Radio? What does this meanForscanner

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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby CarterB » Fri Aug 19, 2011 3:44 pm

Wideband (25KHz splits) to narrowband (12.5 KHz splits) mandatory by Jan 1 2013. Then to 6.25KHz splits sometime in the future (already being worked on) Some scanners are tunable to frequency splits, others not. If you have older scanner you will still be able to hear a narrow band transmission dead center on a frequency, but it may be scratchy.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby Ken W2KB » Sat Aug 20, 2011 7:29 pm

CarterB wrote:Wideband (25KHz splits) to narrowband (12.5 KHz splits) mandatory by Jan 1 2013. Then to 6.25KHz splits sometime in the future (already being worked on) Some scanners are tunable to frequency splits, others not. If you have older scanner you will still be able to hear a narrow band transmission dead center on a frequency, but it may be scratchy.


Note also it is my understanding that the 6.25kHz splits will be exclusively digital. The bandwidth is too narrow for FM to convey the intelligence.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby CarterB » Sun Aug 21, 2011 11:38 am

Ken, you are correct, 6.25 will be exclusively digital, as of now at least. I-Com and Kenwood are already manufacturing/selling 6.25 digital radios.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby CPSK » Sun Sep 25, 2011 4:07 pm

Hello;
I am monitoring RR's in the Northern NJ area for years, and recently, I am having trouble hearing the communications, as the volume level is way down.
Then I started hearing RR employees (on the radio) talking about narrow band radios.
Today, I re-programmed my Yaesu/Vertex VX-150 to receive narrow band on the RR freqs I have in memory. Now at least I can hear their radios.

One thing I want to point out about narrow vs wide band FM: The center frequency does not change, thus you do not need to reprogram the actual frequency, as long as the AAR channels don't change. That said, when new channels are added at 12.5Khz spacing in-between the old 25Khz spacing, you will need to reprogram your radio to receive those new frequencies.
If you are listening to a narrow band signal on a wide band radio, the audio will be lower, but should not be scratchy, as the center frequency has not changed.
If you are receiving a wide band signal on a narrow band radio, the audio level will be somewhat higher, and, depending on your radio's tolerance to out of bandwidth signals, it could sound scratchy, due to the fact that it is being clipped out of the bandpass filters in your radio.

Eventually, the FCC will require 6.5Khz spacing, and all radios with that spacing will be digital. You will need a new scanner to continue to listen to RR's at that time. But rest assured, that is a long way into the future.

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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby EMTRailfan » Sun Apr 15, 2012 8:02 am

The new 7.5kHz spaced frequencies in VHF (12.5 from 25 in UHF) aren't actually what everyone mistakenly refers to as "narrowband". The actual narrowbanding is a needed fix because now that we have the new 7.5kHz spacing in between the old 15kHz spaced freqs., the amplitude of the wideband waves from the neighboring freqs. overlap and interfere with the new freqs., so the amplitude of all freqs. had to be shortened (narrowbanded) to eliminate the interference. How I understand is that we will lose approx. 10% of our radio reception area by changing to narrowband, so if you were hearing an distant, scratchy transmission from a fringe area before in the wideband, you will most likely not hear a transmission from that same location from a narrowband transmission. As for programming your scanner, it will either take the new 7.5 kHz freq. directly if capable, or it may convert it to the next freq. up or down that the tuning board is capable of in which you "should" still hear it. My home scanner did the same thing with a few of our local police freqs., and it still picks them up fine.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby Steve F45 » Sun Apr 15, 2012 2:29 pm

how do you know if you have a scanner that can be reprogammed for the narrowband switch? I have a radioshack pro97 from 2006.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby Ken W2KB » Tue Apr 17, 2012 9:28 pm

Steve F45 wrote:how do you know if you have a scanner that can be reprogammed for the narrowband switch? I have a radioshack pro97 from 2006.


(1) Read the specs in the manual for the radio. :-)

(2) Try programming a frequency 7.5 kHz away from a known channel. If it "takes" then OK.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby EMTRailfan » Wed Apr 18, 2012 8:55 am

Ken W2KB wrote:
Steve F45 wrote:how do you know if you have a scanner that can be reprogammed for the narrowband switch? I have a radioshack pro97 from 2006.


(1) Read the specs in the manual for the radio. :-)

(2) Try programming a frequency 7.5 kHz away from a known channel. If it "takes" then OK.


And like I said above and Ken kind of said, it may not take the actual 7.5 kHz freq., but will convert it to the closest freq. that the scanner's tuning board is capable of like my PRO-2034 did here at home for our county's police freqs. Actual freq.-158.7975, in which my scanner converted to 158.800 and I still hear it fine.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby CSXT7590 » Tue Feb 05, 2013 6:06 pm

I have a motorola HT1000 from Norfolk southern programmed to CSX frequencies

Since its a narrowband model "DN" can i listen to an even tighter band split-6.25 MHz?

I would appreciate any info.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby DutchRailnut » Tue Feb 05, 2013 7:31 pm

Railroads will not go for 6.25 bandsplit untill mandated, and its not in near future.
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Re: Wideband ro Narrow Band Radio? What does this meanForsca

Postby CarterB » Wed Feb 06, 2013 9:59 am

All current and future 6.25KHz splits FCC licensed frequencies are strictly digital, no analog usage.
Users who want to go digital can license now to 'preserve' their frequencies on the 12.5 and 6.25 splits concurrently (UHF)
VHF goes to 7.5KHz splits and potentially +/- 2.5KHz offsets in the future.
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