The Pesky
Details on PTT Controls
CAPABILITY:
Picture a pyramid and think of a single
repeater sitting at the top and 100
repeaters sitting around the base.
Consider coverage to be only in the
horizontal plane. The 1 repeater at
the top covers a small area, around the peak
of the triangle. Now down at the
bottom is an area very much larger where a
hundred repeaters are used to cover this
base. The talkgroup is the vehicle that
carries the audio but also signals the
c-Bridge just how to route connections
to only the repeater at the peak or all
repeaters at the base to talk to each other and
under what conditions.
So back
to the repeater sitting at the top. It may
handle special talkgroups such as Local 1
and Local 2. The 1 and 2 denote which
timeslot is used for any particular
talkgroup and not simply that they are two
different talkgroups. Which timeslot
you are operating is important to know to
appreciate the advantages of having two
independent voice timeslots, which become more
apparent later. A "Local" talkgroup is only routed to
this single repeater (normally), while
"Worldwide" is routed to every Ham DMR in the
world (in theory and concept) for the very
widest footprint of coverage, just like the
wide area around the base of a pyramid.
Between
these two extremes are the nuts and bolts of
Ham DMR. Only PNW talkgroups will be
discussed here in an effort to keep the
information on point and try to keep it
relatively simple. But there is much
heavy lifting being done with these
talkgroups on the back end and some confusion
is common when trying to work with these
nuts and bolts, especially so for our newer
users coming from the more simple FM
repeater world.
One other
talkgroup control types exist and they are
Master
Control Talkgroups. These
MCT's
switch most network talkgroups On or Off on a
per manager (IPSC network) basis. Newly
implemented managers will be created using
the master control talkgroup structure
rather than based on hundreds of hold-off
timers/custom programming into a new
manager. It is possible that some
hold-offs will supplement the master
talkgroups. This will mean that all
control will be in the hands of a user
rather than a complex formula of hold-offs.
This will enable creating a new manager in
less than an hour instead of many hours and is a huge
timesaver for the c-Bridge admin. In
practice, it is suggested that a user who
wants to chat on a certain talkgroup simply
kerchunk the master off talkgroup, then PTT
the main talkgroup on when done.
Local 1 and Local 2 are sorta like MCT's but with shorter
hold off times but will work
with the same ability to control all
networked talkgroups off for a few minutes,
typically 5 minutes. More on this master control concept in the
PTT
page.
PURPOSE: Talkgroups have a purpose
and they can be based on geography, task,
diagnostics, language, politics (between the
c-Bridge groups not Governor Inslee),
enabling timers, control and various special
purposes other than voice calls. Most
talkgroups are based primarily on geography
in some fashion. States are very
common though regions, telephone area
codes and postal zip codes are used as well.
Once a
purpose is selected, then more criteria is
added into the mixing bowl to enable the use
of, for example, a statewide talkgroup such as
Washington 1. Most important is to which
repeaters to route that talkgroup and if
that talkgroup
is on full time or normally muted or
inactive until a user keys up on the
talkgroup to enable it. All this
criteria is programmed into the c-Bridge so
that every repeater passes the traffic when it
should. The programming is extensive
and be a thousand lines of code for a single
busy repeater or network of repeaters.
CONTROL: More completely explained
in
PTT
but more simply here is the ability to turn
on talkgroup and disconnect other talkgroups to accomplish
routing tasks. This is accomplished
actively
by the local user for the most part, either
actively via
MCT
or somewhat passively in the background. The
background work can affect the local user
but for the most-part, the c-Bridge bows to
the local repeater user's activity, though
MCT
will override the background settings.
There are
2 primary tasks that occur when you transmit
during a conversation or just briefly with a
kerchunk. The most important task is
to turn-off all other talkgroups on the same
timeslot that might possibly go active.
These transmissions also starts their
hold-off timers. These hold-off timers are typically set for
3 minutes. This is sufficiently long so
that a conversation is not interrupted or
high jacked by another talkgroup coming in
from the larger network. Some higher
priority talkgroups have longer hold off
timers of 4, 5 and 10 minutes. For
example, Locals are typically set for 5
minute hold-offs. Some very specific
or limited talkgroups might set 1 or 2 hour
long hold-off timers.
The other
primary task is to enable a talkgroup that
is normally muted or not patched to a
repeater. These are called PTT
talkgroups and they can be turned on simply
by transmitting briefly as is a kerchunk. One should
listen for a moment as the PTT talkgroup may
be in use. Unfortunately, while your
PTT action is processed immediately on the
local repeater, that actual connection from
other users is not made until their active
transmission ceases. You would then
hear the other side of that conversation.
Other
lesser tasks are occurring during a
conversation as 2 or more timers are in play
on any conversation, both on your local
repeater as well as the other end or ends of
a conversation between 2 or more hams.
This is where more complexity is involved so
it all gets trickier. There are 2
basic ways to view the state of your local
Talkgroups.
1)
Master
Control: The newer IPSC network
managers may have special talkgroups that
turn all TG's off by timeslot for 29
minutes or on for 59 minutes. 29
minutes is long enough for most
conversations to run without interruption
from other talkgroups. 59 minutes is a
reasonable listening period to general
monitoring. Older managers may have
some or all talkgroups retrofitted as well.
Local 1 and Local 2 will be typical MCT's
though there timers may be shorter than the
dedicated MCT's.
If a user
wishes to have a conversation, then kerchunk
the MCT Off for TS 1 or TS 2 and then
kerchunk back on the talkgroup you wish to
use. When done conversing, simply
kerchunk the timeslot back to normal.
Full time
talkgroups will be turned back on (default).
PTT talkgroups may or may not be activated
depending on the preferences of the repeater
owner and/or the IPSC network manager.
The 59/29 timers are default and may be
implemented differently as well. See
MCT
for more information.
2)
Passive: The local repeater is idle.
This means that all fulltime talkgroups
are patched and the first one to go active,
grabs the timeslot and you hear that audio.
If the
timeslot stays passive, in other works, no local user keys
up on any talkgroup on that timeslot, any
networked traffic can come in and be
heard...it could be 2 or 20 different
talkgroups in random fashion. The
local repeater is simply waiting for the
first talkgroup to go active during any short or
long period of timeslot idle (no active
conversation).
If you
wish to follow a conversation without the
random interruptions of other networked
talkgroups, simply kerchunk the desired talkgroup.
That kerchunk will enable at minimum, a 3
minute hold-off timer to disable the normal
talkgroups that are carried full time or any
PTT talkgroups that happen to still be
active.
You should remember all attempts to talk or kerchunk
must be done during that brief idle time
between transmissions of the active talkers on
any talkgroup that you hear.
This is
why we suggest that turnarounds
pause 1 to 2 seconds, so that you or anyone
else on any repeater anywhere is able to
brake into a conversation or kerchunk out of an active talkgroup. It
is important to remember that your kerchunk
may not be acted on immediately. It is
quite possible that it may be delayed until
a current talker ends their transmission.
The same applies when you kerchunk a PTT
talkgroup into the active state, you may miss the
balance of of the current talkers
transmission before the activation is
completed. Don't get frustrated by the
delays. This really is just the
opposite of HF where quick-keying is the
SOP. Quick keying is counter
productive in DMR. Please be patient when the system is
busy.
Believe
it or not, this is the simple state, active
state has much more going on.
3)
Active: The local repeater is
actively in use by a local user (IE:
transmitted within the past few minutes,
timers are running, certain talkgroups are
being held-off, others may be still be active
but only one talkgroup on the timeslot should be
active ideally. Sometimes higher
priority talkgroups may still be able to barge in
on that local users talkgroup. This is
the more complex and tends to be confusing
for new DMR users.
So let's
try some real world examples, beginning with
Local 1 since it is as simple a situation as
there is on the PNW network. Local 2
is similar and likely is the best
Local talkgroup to use only because this
allows timeslot
1, the PNW primary timeslot, to remain open and
available for other users on the same
repeater. Local 1 likely is THE
highest priority talkgroup on the PNW
network. Local talkgroups are universally used 5
to 1 over the next most active talkgroup
(TAC 310) across the USA.
EXAMPLES:
1) Local 1
is one of the highest priority talkgroups as
DMR hams tend to want to talk to their local
friends but networked talkgroups are still
important to everyone.
Local 1
generally has a 5 minute hold-off timer in
place. Most talkgroups have only 3
minutes. This means that when keying
up on Local 1, ALL timeslot 1 talkgroups are
held off for 5 minutes unless the timer is
renewed by the local user transmission either through a
kerchunk or more likely, an ongoing Local 1
conversation. This insures that some
long-winded network activity doesn't
pre-empt your conversation.
Once the
conversation has ended, the 10 minute timer
continues to run, and continues to hold-off all
network activity. In order to override
that residual timer, if so desired, simply
kerchunk
the talkgroup that you want to use or
to
"reactivate" (typically PNW-1 or your
statewide). Or do nothing and
the default state will return in 10 minutes.
2)
TAC 310 is a popular talkgroup on PNW's
timeslot 2. Timeslot 2 has lower
priority over timeslot 1 though the two
timeslots are completely independent of each
other. Ttimeslot 2 has many more
talkgroups to contend with though it still
works in the same fashion as timeslot 1.
The
bigger difference is that there tends to be
much more traffic from the network rather
than traffic which is created by local users.
This means nothing more than you are
more likely to have a bit less control over the
talkgroups and a bit more network traffic taking
over local traffic.
Local
traffic on a repeater, no matter the
talkgroup keeps that timeslot under the
control of the local user. So when
talking to your local users or other PNW users
on PNW originated talkgroups,
the control is more uniform. The users of PNW
tend to be on the same page,
meaning all under the same timers and
settings, without the randomness of other
network traffic barging in. So timeslot
1 is more efficient and less frustrating
since you are
not dealing with thousands of other users
who may or may not have a better
understanding of the talkgroup dynamics.
Most
timeslot 2 talkgroups have 3 minute hold-off
timers and most are also on PTT. So
until you hit PTT. So until you enable
a talkgroup, it is fairly quiet.
As only one talkgroup may occupy a timeslot at a
time, heavy regulation of the talkgroups on
timeslot 1 is necessary. That heavy
regulation takes the form of PTT enabling.
So
getting back to TAC 310 use, remember that
it is a PTT talkgroup and you should keep that 3 minute
hold-off timer active or you will likely loose the talkgroup
traffic that you
may be interested in listening to. So
kerchunk within that 3 minute window or
take your chances on ending up listening to
another talkgroup that has gone active
during that 3 minute window.
There is
a confusing wrinkle on PTT talkgroups as
many can be on PTT and active at the same
time. That may not make
sense based on my earlier statement about
only a single talkgroup may be active at a
time on the same timeslot, but what can happen is
if you have enabled TAC 310, TAC 1,
Bridge and 3 others in rapid succession,
which turned on all the hold-off timers but
ALSO all the PTT turn-on timers. The PTT
turn-on timers all run at the same time but
the last kerchunk controls the turn-off
timers. This means if you are a
rapid-fire channel
changing kerchunker, you could enable many sets of timers...all running
simultaneously, which can affect what you
really wish to listen to at any particular
time. Just keep in mind, that if you
nothing for 10 minutes, everything is
likely to return to normal state.
Rapid talkgroup hopping does allow time for
responses from users if that is your goal,
so slowing down will enable a more positive
experience.
MISCELLANEOUS OPERATING THOUGHTS:
You cannot hurt the system or network
when you use it, test with it or try to
break it. But you can get confused on the
current state. We would encourage you
to play, experiment, chat with friends and
figure it out...or ask questions in the
Yahoo Group.
If your
repeater or IPSC network uses Local
extensively, if possible, use Local 2 as the
primary talkgroup. This allows your
timeslot 1 to remain open to your statewide
and PNW 1 talkgroups to remain available for
use. If you use Local 1 primarily,
then there is little way for other PNW users
to contact your users nor can your users
chat with other parts of the PNW network.
If
nothing else, when done talking on any
timeslot 1 talkgroup, especially the popular
Local 1, just kerchunk on PNW 1 or your
statewide to sorta put things back to
normal. If you don't, it can be 3 to 5
minutes (typically) before the timeslot goes
back to normal or the passive/idle mode.
Until those timers toll, other PNW traffic
will be missed.
When you
do announce your call on a talkgroup, more
especially on PNW 1, consider saying
something more than "W7WOW listening".
If you are testing, say so. If you are
seeking a conversation, say something
compelling. It is likely that many are
listening but otherwise occupied with other
tasks and may not pick up the HT and
respond. This author will always
respond to a request for a test or a
confirmation of audio or a direct call if
possible, but seldom to someone announcing
that they are listening as it tends to
interfere with work that that needs two
hands and 10 fingers. Somewhat on
point is this article:
The
Friendly Repeater.
Many
users also scan or have RX Groups enabled.
When you make a call, the call may be missed
or missed in part. Keying up and
saying something that puts the call and
purpose of the call, later in that call, can
improve the chances of a response. It
is very helpful when making your call, to
state the talkgroup that you are using as
this will enable a scanning user to know
which talkgroup to respond on. Seldom
is a user looking at the display as a
short car comes in, so unless you state your
information clearly, they are less likely to
respond.. Something like this
announcement rolls these suggestions into
this example: "Good morning everyone, this
is W7WOW mobile on PNW-1 from Redmond on our
way to visit Governor Inslee". Over
the top, yes...but likely to get a response.
If
possible, monitor the PNW c-Bridge
Netwatch
screen or log in to the c-Bridge to see a
bit more behind the scenes workings.
If you are actively experimenting or in
conversation, you can see exactly what is
happening on the network. This
includes your signal strength into your
repeater, which talkgroups are active, who
has been active recently as well as which
repeater in the world they used. Well
worth taking a look at
Netwatch.
If you
use a networked talkgroup, you should have an
understanding of the proper use if you
read the talkgroup list above. If you
are not sure, ask on PNW 1 or in the Yahoo
Group. A 2-3 minute conversation on a
talkgroup that was inappropriate is not
catastrophic, so don't fret if someone dings
you for misuse and that should NOT happen on
PNW. Some of the other DMR groups
simply are too tightly wound and have short
fuses, typically because new users don't
know the rules and it is quite a problem in
their little worlds. If you get some
criticism (audio levels are very common),
take it in stride, factor it into your next
use of that talkgroup and move forward.
Don't abandon the DMR ship. It can be
a complex sphere and no one person knows it
all or has a lock on any particular aspect
of DMR.
If you
have 2 radios, try listening to all
talkgroups on each timeslot. PNW
traffic is likely to be on timeslot 1 while
the network traffic is on timeslot 2.
Timeslot 2 is likely to be far busier and
you could miss a call or PNW traffic on
timeslot 1. A combination of RX
Groups and scan can minimize some of the
missed traffic as a scan list can be set to
a timeslot 1 talkgroup. This is a
an advanced
topic in it's own right but with the
use of Digital Monitor/Promiscuous Mode, RX
and Scan is hardly needed for DMR
monitoring.
Ask
questions on the Yahoo Group. Everyone
was new at some point in time and there will
always be newer hams coming to DMR. We
all should treat them just as well as we
had been treated. Pay it forward, yada
yada...and have fun. DMR is still very
cool after 7 years for this author. My
thanks to Scott, NS7C, for providing
additional clarity to this page.