Digital Voice with VXD-720/7200
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kayn1n32008
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It is called DMR, Motorola calls it MotoTRBO. It is 2 slot TDMA using a 12.5KHz channel. It is a commercial protocol, that hams are starting to use quite widely both in North America and in Europe. Check out DMR-MARC (google DMR-MARC) lots of good info there. Vertex, Motorola, Harris, Hytera, Tait, Kenwood and Simoco are some of the companies that are making DMR equipment.
It is called DMR, Motorola calls it MotoTRBO. It is 2 slot TDMA using a 12.5KHz channel. It is a commercial protocol, that hams are starting to use quite widely both in North America and in Europe. Check out DMR-MARC (google DMR-MARC) lots of good info there. Vertex, Motorola, Harris, Hytera, Tait, Kenwood and Simoco are some of the companies that are making DMR equipment.
W2NJS
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Just to "cover all the bases" for the OP, many hams are also using digital P25 mode in many parts of the USA. P25 is the digital mode used by many public service agencies. Radios usable for P25 are made by Motorola, Thales, Vertex, Tait, and probably others as well. In my home area around DC we have a number of P25 repeaters in operation at this time.
JPSan
Member
To see if DMR MotoTRBO is in your area type your state name in the search box.
More and more Amateur TRBO systems are popping up.
http://www.n6dva.org/trbo-database/trbo_repeaters_view.php
In Arkansas the only digital I currently know of is one D-STAR repeater... that repeater is located too far for me to be able to utilize it as well as the D-STAR equipment being so expensive.
Since I'm a Vertex dealer I have the VXD radios and I've played around with digital on my business band frequency but I had no ideal that it was being used on the amateur bands.
Since I'm a Vertex dealer I have the VXD radios and I've played around with digital on my business band frequency but I had no ideal that it was being used on the amateur bands.
I stand corrected! LOL
I have been using both, the VXD-720 HT and VXD-7200. They are easy to program for DMR ham radio
use. All you need is the Time Slot (1 or 2), Color Code, and Talkgroup. There are three DMR repeaters
in my area (Raleigh NC) and a wide coverage, mixed-mode P25 repeater. All are currently UHF but VHF is also being used in some areas.
The Vertex VXD radios will also do conventional analog as well. Easy to set up in the programming
software, which is necessary along with a specific programming cable, as the radios cannot be
programmed from the front panel/keypad. Out of curiosity, I opened my 720 and looked at the PCB
board. There is a Motorola 'Batwing' logo on the PCB. The VXD radios are made by Motorola for
Vertex. Basically, the VXD-720 is related to the Motorola XPR6500 (no internal GPS) and the 7200
is related to the XPR4500. I know someone that has a 7200 in a mobile application. He used the
XPR4550 remote separation kit on his 7200. Works fine.
Vertex Standard | VXD-720
Vertex Standard | VXD-7200
Vertex has also announced another line of radios that are DMR and analog ready:
Vertex Standard | EVX-530
For more info on DMR for Ham Radio use, check out these links.
DMR-MARC Network
TRBO-6 IPSC Network, a community of Amateur Radio MotoTRBO IPSC Repeaters in the USA
Yahoo Groups:
http://groups.yahoo.com/group/MOTOTRBO/
http://groups.yahoo.com/group/mototrbousa/
use. All you need is the Time Slot (1 or 2), Color Code, and Talkgroup. There are three DMR repeaters
in my area (Raleigh NC) and a wide coverage, mixed-mode P25 repeater. All are currently UHF but VHF is also being used in some areas.
The Vertex VXD radios will also do conventional analog as well. Easy to set up in the programming
software, which is necessary along with a specific programming cable, as the radios cannot be
programmed from the front panel/keypad. Out of curiosity, I opened my 720 and looked at the PCB
board. There is a Motorola 'Batwing' logo on the PCB. The VXD radios are made by Motorola for
Vertex. Basically, the VXD-720 is related to the Motorola XPR6500 (no internal GPS) and the 7200
is related to the XPR4500. I know someone that has a 7200 in a mobile application. He used the
XPR4550 remote separation kit on his 7200. Works fine.
Vertex Standard | VXD-720
Vertex Standard | VXD-7200
Vertex has also announced another line of radios that are DMR and analog ready:
Vertex Standard | EVX-530
For more info on DMR for Ham Radio use, check out these links.
DMR-MARC Network
TRBO-6 IPSC Network, a community of Amateur Radio MotoTRBO IPSC Repeaters in the USA
Yahoo Groups:
http://groups.yahoo.com/group/MOTOTRBO/
http://groups.yahoo.com/group/mototrbousa/
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How does the talkgroups work?
What I am asking is if you've got 3 talkgroups on the same time slot (and same frequency) what happens if all three talkgroups are being used at the same time.... Will it sound like someone talking on top of someone else?
I know the repeater can do two transmissions as once (time slot 1 and 2) but can it do multiple talkgroups on each time slot as well?
What I am asking is if you've got 3 talkgroups on the same time slot (and same frequency) what happens if all three talkgroups are being used at the same time.... Will it sound like someone talking on top of someone else?
I know the repeater can do two transmissions as once (time slot 1 and 2) but can it do multiple talkgroups on each time slot as well?
I have yet to experience a talkgroup congestion issue. Looking at the DMR-MARC site, I found this bit of info:
"While using multiple talkgroups for a various purposes may be handy, the downside in having "too many" talkgroups is that there is likelihood of congestion or busies on the two timeslots. So a balance is likely wise as well as not carrying all talkgroups on all networks managed by any single c-Bridge. As more c-Bridges come online, the various talkgroups increase the efficiency of use on the 2 timeslots."
DCI- c-Bridge Implementation - TalkGroups
I'm guessing the c-Bridge controller allows TalkGroups in a priority order.
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