Ham Radio: DMR versus D-Star and why I am going to D-star and hoping DMR becomes cracked wide open by ham operators.
I arrived and was surprised at the range I was getting from DMR on 440 and had a blast talking on the North America group to other hams all over the USA and Canada. until it started to blank out for some reason in the middle of a QSO. I though it was my radio until I got to the hotel and started to read up on causes.
It seems that DMR has 2 timeslots and repeaters that have multiple call groups on a single timeslot will get other hams cutting them off without knowing it. This is what was happening to me, another ham was kicking me off of the north america talk group and I was knocking him off. no warning just audio gone, and if you did not specifically go looking for this information, you would never ever know it. So to support the entire talk group spread you really need 5 DMR repeaters.
Well also come to find out a radio to radio conversation ALSO takes up a timeslot so now you can unknowingly knock others off the repeater or tie it up. This makes DMR not very good for ham radio the way everyone is using them.
mototrbo DMR repeaters should be set up with only 2 groups available. timeslot 1 is local chat, timeslot 2 is the NA channel. and you do not do long QSO's on the NA channel. This really limits the usefulness that is promised but did not completely make me write it off. I think it's a great mode with dirt cheap great quality radios.... and was going to look at buying gear to put a DMR repeater on the air in my home town... Then my enthusiasim drained.....
a mototrbo repeater is about $3000 if you want to program it that is another $300 in software and another $150 in the cable. You also need a set of cans, cheaper cans can do a 7.5mhz spread so your repeater will be "wierd" for $500 then you have tower, antenna and broadband and router//software to join the worldwide DMR network. Suddenly that free repeater location you know of becomes a $70 a month rent repeater location for broadband directly to it. Overall if you have a tower and location with antenna already set up you need $6000 to spend to get a Motorola DMR repeater on the air. That means only the rich ham clubs.
So I look at D-star. Radios are $400 instead of $95 but repeaters can be built easily AND I can put a mini gateway in my home on my own internet to get to the global D-star network for only around $200 spent! You also do not have the kick other hams off the repeater without warning problem. But you alienate the poor hams over the rich ones. Yes I can easily afford a $400 handheld, but most cant. Many cant afford that $95 china DMR radio but it is a lot easier reach than the only icom offerings out there. So it is only price? Nope.
D-Star was made for ham radio use, you do not have to register your radio number like you have to with DMR, you can program your dStar radio and just go on the air. It operates more closely to what a ham radio operator is used to and new users will not cause communication problems like they do on DMR simply because they dont know they need to check ALL The talk groups before they start using the repeater.
I like DMR and what it can do, and the range is insane compared to traditional FM 440. I am all the way out in Shaumberg, IL and still talking to the downtown Chicago repeater with my handi talkie. the sound quality blows away all analog modes hard. But sadly until someone cracks the Motorola DMR code to get other china repeaters ont he DMR-MARC network its a closed system where only the rich can get a new repeated added to it. which is sad because I know that DMR with cheap radios and the North America talk group would get new hams excited about ham radio. Cracking the motorola DMR network protocol so that hams can set up local home gateways will really make the whole DMR network explode. and if someone finds a way to translate from the Hytera chinese DMR repeater networks to bridge the Motorola DMR-MARC network It will really make the whole network so much more versatile overnight. I want it to succeed, and Motorola could do this incredibly fast for ham radio operators by opening up their protocols completely and give us hams the keys to the workings of the network packets... Otherwise it will take hacking the protocols by hams that are far better at it than I am to make that change.
I know I felt like I did back in the 80's when I was a 17 year old with a fresh tech ticket in my hand and talking on the local repeaters that were teeming with other hams to talk to. Today the FM repeaters are dead, but the Digital modes on national talk groups are like our local repeaters were back in the 80's... exciting, friendly, and makes you want to be a ham radio operator again....