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NFM vs FM and stepping ?

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Sjinndoawi

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Feb 12, 2007
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Ok, if your tuning steps are less than 25kHz isn't anything below 25kHz consider NFW even though a manufacture staes it FM ? So then we could say that .01,1,5,6.25,7,8.33,12.5,15,20 tuning steps are all NFM?
 

JungleJim

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Sep 21, 2007
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Not necessarily. First the background. A few years back the FCC saw how crowded the VHF and UHF bands had become so they decided to double the number of channels in the UHF band by chaning the channel separation from 25 kHz to 12.5 kHz and in VHF from 15 kHz to 7.5 kHz.

The bandwidth of an FM channel is ± 5 kHz and is now known as WFM or wide FM. With the new narrower channel spacing the bandwidth had to go down to prevent channels from overlapping so the bandwidth was cut to ±2.5 kHz and is known as NFM or narrow FM. Manufacturers were ordered to make equipment capable of the new specifications and new licenses were issued at the new narrow FM for both 12.5 and 25 kHz channels. Existing licensed channels will eventually all be converted to the new narrow FM. I don't know the time line though. The channel spacing does not directly determine the bandwidth.

If you set your radio to wide FM on a NFM channel you will still be able to hear, it will just be lower volume. Or if you set it to NFM on a WFM channel the audio will be louder and maybe a little distorted as the narrower IF filters in the radio may chop off the outer sides of the signal.
 

lugoffman

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lugoffman said:
do what ????? what are you asking not tring to be a butt, but what are you asking
would like to say im sorry my cousin got on here on my name when i went to the car and im sorry he wrote this hes a retard please disregard what this says
 
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