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4604Re: [BCD396XT] Re: Audio level differences...

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  • Jerry Dubzak - W2GLD
    Oct 4, 2010
    • 0 Attachment
      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
      > >> � 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...
      > >>
      > >> �
      > >> 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]
      > >
      > >
      > >
      > > ------------------------------------
      > >
      > > Yahoo! Groups Links
      > >
      > >
      > >
      > >
      >



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