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4612Re: [BCD396XT] Re: Audio level differences...

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  • MCH
    Oct 5, 2010
    • 0 Attachment
      Eventually, most channels will be NFM. In fact, it's required of most
      services (but not all) by 2013 and many are changing over now.

      You likely have several NFM channels in your area already.

      I have around 10% NFMs in my area. Well, maybe that many.

      Even if they are on traditional frequencies, they may be using NFM
      rather than FM, or may be soon.

      Joe M.

      Lance Star wrote:
      > Perhaps all the VHF HI band PS systems in my radio will need to be globally changed to FM mode. Since I don't have any 6.25khz allocated freqs. In fact I have yet to come across any...
      >
      > For everything else, there's programming software. Would be interested to hear Paul's response to this topic's last thread. Perhaps the default band plan setting for modulation should be FM for this radio...
      >
      >
      >
      >
      >
      > ----- Original Message -----
      > From: MCH <mch@...>
      > To: BCD396XT@yahoogroups.com
      > Date: Mon, 04 Oct 2010 21:43:47 -0400
      > Subject: Re: [BCD396XT] Re: Audio level differences...
      >
      >>
      >> The first one definitely should be NFM.
      >>
      >> The second one is likely FM, but it could legally be used for or
      >> converted to a NFM system.
      >>
      >> The emission designations are maximum allowed bandwidth, not necessarily
      >> exact figures. So, a licensee for a 20K0 bandwidth channel (20.0 kHz to
      >> put it in non-FCC-eeze) could be used for an 11K0 signal.
      >>
      >> The rest of the emission designator will put other restrictions on the
      >> licensee, too, but they don't apply to what we are talking about.
      >>
      >> On second look, the .6500 channel is a splinter channel, and I didn't
      >> think there were any licenses that wide (20K0) issued on T-band splinter
      >> channels. Or were your examples hypothetical?
      >>
      >> Joe M.
      >>
      >> Jerry Dubzak - W2GLD wrote:
      >>> Joe,
      >>>
      >>> >From what I see here then, the following should be true:
      >>>
      >>> 508.9875 with an emission designator of 11K should be NFM
      >>>
      >>> 508.6500 with an emission designator of 20K should be FM
      >>>
      >>> Is this a true statement???
      >>>
      >>>
      >>> On Oct 04, 2010, at 12:03 PM, MCH wrote:
      >>>
      >>>> Uniden mode / Common designation / Deviation / Bandwidth
      >>>> NFM SNFM 2.5 kHz 11.0 kHz
      >>>> FM NBFM 5.0 kHz 16.0 kHz
      >>>> WFM Wide FM 25.0 kHz 100.0 kHz (or 90.0)
      >>>> FMB Wide FM 75.0 kHz 200.0 kHz (or 190.0)
      >>>>
      >>>> Channel spacing is a different issue, and while there are minimum limits
      >>>> for the wider modes, any channel spacing can be used with any mode. For
      >>>> example, SNFM can be used with 25 kHz channel spacing, or 20, or 15, or
      >>>> 12.5, or even 7.5 or 6.25 even though that is technically unsound.
      >>>>
      >>>> But, if you have something operating on 6.25 or 7.5 kHz channels, it is
      >>>> most likely SNFM.
      >>>>
      >>>> WFM is for TV, and FMB is for the "FM" radio band (88-108 MHz).
      >>>>
      >>>> Paul, if the quoted text is accurate, please update the specs.
      >>>>
      >>>> Joe M.
      >>>>
      >>>> w2gld wrote:
      >>>>> UPMan,
      >>>>> Please clarify some information; the link you provided states the
      >>>>> following:
      >>>>>
      >>>>> NFMThe scanner treats the frequency as Narrowband FM modulation (about
      >>>>> 7.5 kHz deviation; also referred to as SNFM in some references).FMThe
      >>>>> scanner treats the frequency as FM modulation (about 15 kHz deviation;
      >>>>> also referred to as NFM in some references).WFMThe scanner treats the
      >>>>> frequency as Wideband FM modulation (over 100 kHz deviation; used for
      >>>>> pre-digital conversion TV broadcast reception and similar).FMBThe
      >>>>> scanner treats the frequency as FM broadcast modulation (about 75 kHz
      >>>>> deviation; used for FM radio station reception and similar).
      >>>>> >From a communications perspective, should the following be true?
      >>>>> "FM" should be 5 kHz maximum deviation, with a channel spacing of 15,
      >>>>> 20, or 25 kHz.
      >>>>> "NFM" should be 2.5 kHz maximum deviation, with a channel spacing of
      >>>>> 6.25, 7.5, or 12.5 kHz.
      >>>>> This setting for most is very ambiguous and has little documentation
      >>>>> from Uniden. For whatever reason, Uniden has taken the standpoint that
      >>>>> almost all VHF, UHF, and SHF traffic should be "NFM" when it follows the
      >>>>> "AUTO" setting. Can you please explain why this is; other than future
      >>>>> FCC licenses will require this setting?
      >>>>> Would it be safe to assume that if a Project-25 (Conventional or
      >>>>> Trunking System) uses 12.5 kHz channel spacing then the setting should
      >>>>> ALWAYS be "NFM"
      >>>>> And if this is true, should Project-16 (Conventional or Trunking
      >>>>> Systems) that use 25.0 kHz channel spacing, should the setting ALWAYS be
      >>>>> "FM"
      >>>>> What I have found in researching the individual FCC licenses for many
      >>>>> agencies is that the emissions designator indicates the appropriate
      >>>>> bandwidth of a frequency and does not always follow the Uniden "AUTO"
      >>>>> setting.
      >>>>> For example, the "New Jersey State Police" use a Motorola Type II
      >>>>> SmartZone trunked radio system within the 800 MHz band. Their licenses
      >>>>> indicate 20K emissions designator, thus a setting of "FM" would be
      >>>>> appropriate in my opinion to allow for the extra bandwidth. The Uniden
      >>>>> scanners always default this to NFM under the "AUTO" setting and this
      >>>>> usually makes the audio horrible to listen to. This case is exactly the
      >>>>> same for the City of Philadelphia's system; which is "full digital -
      >>>>> APCO-25 audio" With the default "NFM" setting, this system is almost
      >>>>> useless to monitor; however, if one changes the setting to "FM" the
      >>>>> system track fine with little issues.
      >>>>> Another example is the "Burlington County, NJ", which is also a Motorola
      >>>>> Type II SmartZone system. Their bandplan indicates 12.5 kHz channel
      >>>>> spacing, thus the audio should be "NFM" correct?
      >>>>> By the explanation in the link you've provided, most communication would
      >>>>> in fact remain "FM" and not the default "AUTO" setting or "NFM".
      >>>>> If I am understanding the text correctly, ONLY the "SUPER-Narrowband"
      >>>>> frequencies such as VHF 7.5 kHz and UHF 6.25 kHz should use the setting
      >>>>> of "NFM", is this a true statement from what Uniden engineers have
      >>>>> designed???
      >>>>> To summarize, when should one use the "NFM" setting vs. the "FM" setting
      >>>>> for general public safety use? Is the "NFM" setting on for the
      >>>>> "SUPER-Narrowband" frequencies, such as those licensed for 7.5 kHz on
      >>>>> VHF and 6.25 kHz on UHF ONLY?
      >>>>> If you could please elaborate on this topic, I am sure many of us would
      >>>>> appreciate it.
      >>>>> Thank you for all your support here on the groups and RadioReference!
      >>>>> Regards,
      >>>>> Jerry - W2GLD
      >>>>>
      >>>>>
      >>>>> --- In BCD396XT@yahoogroups.com, Uniden UPMan <uniden.upman@...> wrote:
      >>>>> http://info.uniden.com/twiki/bin/view/UnidenMan4/EditChannel#Set_Modulat\
      >>>>> ion
      >>>>>> Â UPMan
      >>>>>>
      >>>>>>
      >>>>>>
      >>>>>>
      >>>>>> ________________________________
      >>>>>> From: Lance Star milcom_chaser@...
      >>>>>> To: BCD396XT@yahoogroups.com
      >>>>>> Sent: Fri, October 1, 2010 1:54:52 PM
      >>>>>> Subject: Re: [BCD396XT] Audio level differences...
      >>>>>>
      >>>>>> Â
      >>>>>> Ok, sounds like Close Call is following the band default mappings when
      >>>>> in Auto
      >>>>>> mode for demodulation.
      >>>>>>
      >>>>>> What are the deviation settings in this radio for:
      >>>>>>
      >>>>>> NFM
      >>>>>>
      >>>>>> FM
      >>>>>>
      >>>>>> FMB
      >>>>>>
      >>>>>> I have not looked to see if these are in the specification section
      >>>>> yet.
      >>>>>> Thanks UPMan!
      >>>>>>
      >>>>>> ________________________________
      >>>>>> From: Uniden UPMan uniden.upman@...
      >>>>>> To: BCD396XT@yahoogroups.com
      >>>>>> Sent: Fri, October 1, 2010 11:27:53 AM
      >>>>>> Subject: Re: [BCD396XT] Audio level differences...
      >>>>>>
      >>>>>> Since most band defaults in the scanner are NFM, I'd suspect that the
      >>>>> service is
      >>>>>> transmitting FM and you have the channel programmed correctly as FM.
      >>>>> But, on a
      >>>>>> Close Call hit, FM will overmodulate NFM demodulation and result in
      >>>>> the audio
      >>>>>> being much louder.
      >>>>>> UPMan
      >>>>>>
      >>>>>> ________________________________
      >>>>>> From: milcom_chaser milcom_chaser@...
      >>>>>> To: BCD396XT@yahoogroups.com
      >>>>>> Sent: Fri, October 1, 2010 1:14:36 PM
      >>>>>> Subject: [BCD396XT] Audio level differences...
      >>>>>>
      >>>>>> I was scanning some conventional public service frequencies with close
      >>>>> call in
      >>>>>> DND mode. I noticed when close call came across a local PD frequency,
      >>>>> it's audio
      >>>>>> level was much louder than the same one programmed into the radio
      >>>>> within a
      >>>>>> group. I have not check the AGC level settings, but wondered if anyone
      >>>>> else has
      >>>>>> noticed this as well?
      >>>>>>
      >>>>>> [Non-text portions of this message have been removed]
      >>>>>>
      >>>>>> [Non-text portions of this message have been removed]
      >>>>>>
      >>>>>>
      >>>>>>
      >>>>>>
      >>>>>>
      >>>>>>
      >>>>>>
      >>>>>> [Non-text portions of this message have been removed]
      >>>>>>
      >>>>>
      >>>>> [Non-text portions of this message have been removed]
      >>>>>
      >>>>>
      >>>>>
      >>>>> ------------------------------------
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      >>>
      >>>
      >>> [Non-text portions of this message have been removed]
      >>>
      >>>
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      >>
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