[TrunkCom] Control Frequency Only Mode

Thu Oct 27 10:00:57 EDT 2005

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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