[TrunkCom] Control Frequency Only Mode

Thu Oct 27 10:06:32 EDT 2005

>From what I have been able to gather from reading on this, splinter
systems use frequencies that are in between the regular channel
incruments.  Fr example from 850-866 MHz you might have a system that is a
splinter one will have a frequency in it like 856.050, or something like
that.  These splinter systems are only in the 800 Mhz band, according to
my Pro-96's manual.

On Thu, 27 Oct 2005, JERRY NONE wrote:

> Regular I know but what is a SPLINTER SYSTEM?
>
> --- Jeff Kenyon <at649 at tcnet.org> wrote:
>
> > Do youknow if when rebanding happens if they will be
> > changing base
> > frequencies and other things in older Motorola
> > systems?  I know that with
> > some systems they may be considered to be splinter
> > systems  in this part
> > of the band.
> >
> >
> >
> >
> >
> > On Wed, 26 Oct 2005, Jay Eimer wrote:
> >
> > > Basically, Motorola uses an "absolute" channel
> > number, and EDACS and LTR use
> > > a "relative" one.
> > >
> > > In Motorola systems, there is a base frequency
> > (something like 850.0000) and
> > > a "step" (say 0.0125)  Any frequency that could
> > possibly be used can then be
> > > expressed mathematically as base + (step *
> > channel).  What will break the
> > > scanners with the rebanding is if they change the
> > base (say to 840.0000).
> > > The control channel says the same thing (go to 500
> > translates to go to
> > > 850.0000 + (500 * 0.0125) or 856.250.  If they
> > change the base to 840, then
> > > "go to 500" means go to 846.250, and the old
> > scanner still goes to 856,
> > > instead of 846.
> > >
> > > In EDACS, the control channel says "go to SLOT 3"
> > (I used slot intentionally
> > > to avoid confusion - the computer really does it
> > in binary so the term used
> > > doesn't matter).  The radio (user's) interprets
> > that as "go to memory 3".
> > > The scanner handles that by going to "the channel
> > in this bank ending in
> > > '03'".  So it always works, as long as the right
> > frequency is stored in
> > > memory x03.  If they change the freqs used by the
> > system, you just reprogram
> > > the memories to match.  But that's also why the
> > LCN order matters.  If LCN 1
> > > is 856.0125 and LCN 2 is 857.0125, if you reverse
> > them, you always go to the
> > > wrong frequency.  The scanner goes where the
> > control channel data told it to
> > > go - but the call it expected wasn't there.
> > >
> > > HTH,
> > >
> > > Jay
> > >
> > > -----Original Message-----
> > > From: trunkcom-bounces at mailman.qth.net
> > > [mailto:trunkcom-bounces at mailman.qth.net] On
> > Behalf Of JERRY NONE
> > > Sent: Wednesday, October 26, 2005 13:05
> > > To: Discussion of Monitoring Trunk Radio Systems
> > > Subject: RE: [TrunkCom] Control Frequency Only
> > Mode
> > >
> > > So then why don't we need the L.C.N.s or Channel
> > Numbers for Motorola but we
> > > need them for EDACS and LTR?
> > >
> > > --- bearcat <rwnewbould at comcast.net> wrote:
> > >
> > > > Each 800/900 mhz freq has been aasigned a
> > channel no.  The control
> > > > channel data from the system tells the units
> > which channel no. (hence
> > > > freq) to go to.  The scanner gets the
> > information from the system
> > > > control channel so they can add as many new
> > sites as they need and the
> > > > data will then be on the system control channel
> > so the scanner handles
> > > > if just fine.  This is why rebanding is such and
> > issue the channel
> > > > no.s being sent will make no sense to the
> > scanner.  The advantage to
> > > > using CC only programming is that if something
> > would change on the
> > > > system the scanner user will never miss a beat.
> > If you have all of
> > > > the freqs programmed in a a new site is added
> > you will not hear it.
> > > >
> > > > This is explained to the best of my limited tech
> > knowledge
> > > >
> > > > Rich
> > > >
> > > > -----Original Message-----
> > > > From: trunkcom-bounces at mailman.qth.net
> > > > [mailto:trunkcom-bounces at mailman.qth.net] On
> > Behalf Of JERRY NONE
> > > > Sent: Monday, October 24, 2005 10:58 AM
> > > > To: Discussion of Monitoring Trunk Radio Systems
> > > > Subject: Re: [TrunkCom] Control Frequency Only
> > Mode
> > > >
> > > >
> > > > Does anybody have a copy of this band plan?
> > > >
> > > > --- Jeff Kenyon <at649 at tcnet.org> wrote:
> > > >
> > > > > Hi Jerry, a scanner that doesn't support
> > control only mode will have
> > > > > the frequencies as reference to go to for a
> > transmission.  In
> > > > > control channel only mode, the scanner follows
> > the specific band
> > > > > plan that Motorola has set up for its various
> > bands such as 800 and
> > > > > 900
> > > > MHz
> > > > > trunking so that is
> > > > > how this is all possible, and with control
> > only
> > > > mode
> > > > > you can hear all the
> > > > > transmission, and any subsequent transmission.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On Mon, 24 Oct 2005, JERRY NONE wrote:
> > > > >
> > > > > > Question.  Okay, say for instance you have a
> > > > radio
> > > > > > scanner that does NOT do Control Frequency
> > Only
> > > > > Mode.
> > > > > > So you program in all the frequencies.  So
> > when
> > > > > the
> > > > > > Controller tells Talk group 336 to go to a
> > > > > frequency
> > > > > > of 868.7125, how does a radio scanner in
> > Control Frequency Only
> > > > > > Mode know NOT to go that
> > > > frequency.
> > > > > > Instead the message is heard on one of the
> > > > Control Frequencies.
> > > > > > Also by being in Control Only Mode,
> > > > > does
> > > > > > this prevent the radio scanner from hearing
> > all
> > > > > the
> > > > > > transmissions?  I mean if the system you are
> > monitoring has seven
> > > > > > frequencies and then adds
> > > > > three
> > > > > > more frequencies to accomodate extra users
> > but
> > > > the
> > > > > > Control Frequencies remain @ the same
> > amount,
> > > > > won't
> > > > > > that cut off some transmissions?  What
> > happens
> > > > > then,
> > > > > > do you just hear the priority transmisions?
> > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> ========================================================================
> > > > > > County Of Medina Ohio County Scanner Group:
> > > > > > http://groups.yahoo.com/group/medinascanner/
> > > > > >
> > > > >
> > > >
> > >
> >
> ------------------------------------------------------------------------
> > > > > > Southwest_Parma_Strongsville Scanner Group:
> > > > > >
> > > > >
> > > >
> > >
> >
> http://groups.yahoo.com/group/Southwest_Parma_Strongsville/
> > > > > >
> > > > >
> > > >
> > >
> >
> ------------------------------------------------------------------------
> > > > > > There will be a new radio scanner on the
> > market
> > > > > soon.  Here is the Yahoo Group for that Radio
> > > > > Scanner:
> > http://groups.yahoo.com/group/BCD996T/
> > > > > >
> >
> === message truncated ===
>
>
> ========================================================================
> Southwestern Cuyahoga County Ohio, Parma Ohio & Strongsville Ohio Radio Scanner Group:
> http://groups.yahoo.com/group/Southwest_Parma_Strongsville/
> ------------------------------------------------------------------------
> County Of Medina Ohio County Scanner Group:
> http://groups.yahoo.com/group/medinascanner/
> ========================================================================
>
>
>
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