I’ve had a few people ask me what “time slot”(TS) they should use when setting up a talkgroup on a particular repeater. For DMR Tip 02, I'll focus on answering this and give you links for more information on finding repeaters and configuring your radio correctly.
Here is a good description of what a time slotis byNEDECN:
With a TDMA (time divisionmultiple access) system like DMR, the mobile or portable radios aresynchronized typically by a repeater and assigned a time slot. In DMR Tier 2,there are two time slots, i.e.2-slot TDMA. A mobile radio transmits for 30 milliseconds and then receives for30 milliseconds. It listens for a permission to transmit and then begins a callto all other talk group members who will also receive on that same time slot,e.g., Time Slot 1. Meanwhile, a different group of users on another talk groupcould be using Time Slot 2 simultaneously. Well almost simultaneously, offsetby 30 ms., but you would never know the difference, because two voices can comeout of two radios simultaneously from the same repeater.
Helpful Tip: If you have SmartLoop time slots on your schedule, you will want to take them into consideration when selecting the amount of pins per day. (For example - If you want 20 pins per day, but have 8 SmartLoop time slots then you will want to generate 12 time slots per day for your general schedule.) 4. You’ll have to ask for the person’s free time slots, and match their slot with yours. Plus, if you live in different time zones, you need to coordinate that too. The CTOT is the time, with a window of -5/+10 minutes, when the airplane is required to be at the runway, ready for departure. The slot time controls other standardized events, such as when the airplane can leave the gate (Target Off Block Time, TOBT) and when its engines can be started (Target Start-up Approval Time, TSAT).
A couple more terms before we begin:
Static: The talk group (TG) is always locked / subscribed to by therepeater.Example, The San Diego Hangout(310014) is static on Miguel, but not on the Papa repeaters.So if you tune in, you don’t need to doanything because the repeater is always subscribed to the TG and repeats outany traffic on it.
Dynamic:The group is added to therepeater as soon as you press transmit for a TG that doesn’t already have theTG on it.The TG stays on the repeaterfor 15 minutes.The timer is reset if ithears anyone transmit into the repeater again on that talkgroup.This is why “kerchunking” is acceptable andexpected on DMR repeaters.So if you arejust listening to a dynamic talkgroup and then it disappears all of a sudden,just kerchunk the repeater with that TG again.
Dynamic groups are super cool and the realpower of DMR in my opinion.For example,I have the Qualcomm DMR repeater channel setup for the hangout (310014) so Ican use it in my area.
What TS should I use?
Thenormal time slot (TS) to use for dynamic groups is TS1.
Take a look at area 3 on the graphic below (click on it to enlarge).Thisrepeater page tells you what groups a repeater has as static so that youconfigure your radio correctly…. That is, if the group you want is static (the lock icon) on TS2, make sure you useTS2 on your channel config so that you don’t cause the repeater to subscribe toit twice.
Example:If you use the Papa DMRrepeater on Woodsen lookHERE.You’ll see that the SoCal talkgroup is static on TS2.If you use a repeater that doesn’t have SoCalstatic, the normally accepted practice is to use TS1 for that dynamicgroup.You’ll notice that they remindyou of that at the top of therepeater page.
Brandmeister Repeater PageDetails
The “Slot details” (Section 3) shows what talk groups therepeater is currently subscribed to on each time slot.Themost important thing to pay attention to are what talkgroups are “static” onthis repeater.Static groups aresetup by the repeater owner and are always repeating any traffic heard on thattalk group on the indicated timeslot.Static talkgroups have a small padlock iconon them.If you can't see them,click on the image for a larger version.
This section also shows“dynamic” talkgroups.Instead of a lock,they are a different color and have what looks like a lightning bolt onthem.These are talkgroups that usershave forced the repeater to subscribe to by transmitting to the talkgroup onthe repeater.The talkgroup is active onthe repeater for 15 minutes after the operator transmits.The expire time is reset each time anoperator transmits on the talkgroup.These talkgroups are temporary and will go away after 15 minutes if aham operator doesn’t use it within 15 minutes.So if you want to monitor a talkgroup that isn't static, you need tokerchunk the repeater on that talkgroup a minimum of every 15 minutes if thereare no other users of that on that repeater.(Kerchunking is OK on DMR)
On our example below, thisrepeater’s Timeslot 1 has the San Diego (310670) talkgroup static, and the SanDiego Hangout (310014) dynamic.I causedthe 310014 to be added to the repeater when I used it while writing thispost.Timeslot 2 has the CA (3106),Southwest (3176), SoCal (31066), and USA (31606).
[Noticehow hovering the mouse cursorover a timeslot can display the name. If the timeslot is dynamic, it also displayshow much longer the talkgroup has before it expires unless it is used bysomeone]
NOTE!
If you plan on using a particular talkgroup on a repeater,check to see if that talkgroup is static on that repeater.If so, makesure you use the same timeslot as shown on the configuration page.For example, if you plan on using the CAtalkgroup (3106) on this repeater, be sure to configure your radio to useTimeslot 2 when using this repeater.
You’ll notice that the PapaSystem repeaters all have the CA talkgroup onTimeslot 1.
If you want more detail on all of therepeater info, seethis article.
Free Time Slot Scheduler
Take a look at some of the other tips and articles on DMR HERE.
I hope you found this tip useful.Please use the comments section to submityour questions.
Enjoy and 73,
Old Time Slots Free Game
Christian Claborne