Amateur Radio is beginning to meet [mass-marketed] digital technology, in the form of D-Star technology. Since it is beginning to gain popularity here in West Central Florida, I have made the investment in an entry-level radio, namely the Icom IC-U82, a UHF-only HT. Here’s some of what I’ve learned so far…
First, to clear up a huge misconception: D-Star is NOT Icom’s technology. D-Star was developed by, and is licensed by, the Japan Amateur Radio League. Radio manufacturers who want to incorporate D-Star technology into their radios are paying a license fee to the JARL for the privilege. For the moment, only Icom has made the investment into the technology. Kenwood reportedly has a radio on the market, but it is believed to be a re-branded Icom product, and is not readily available in North America.
The Icom U-82 (and V-82 2-meter version) is a mono-band HT for both analog and digital operation. Out of the box, the x-82 radios are not capable of digital. They both require the purchase of the digital module, which is installed behind an access panel behind the battery. When purchased new, the radio is about $140…the digital board is another $200. Thankfully, I found a package for $250 complete, with a speaker/mic and high-capacity battery. The U-82 is rated up to 5 watts, the V-82 puts out up to 7 watts. Both models are sturdy, well-constructed radios with loud and clear speakers…better than your average HT. It is, however, larger than most HTs on the market. Judging by its limited external connections (speaker, mic, data…no external power), and rugged design, the radio is made to take a beating. Since there is no external DC jack, the only option for charging is drop-in, and the only option for power is the battery.
There are other D-Star radios available, including dual-band HT’s and mobile units.
I quickly learned that everything I already knew about repeater operation, was not enough. D-Star is not a “plug-and-play” system, and Icom radios aren’t always user-friendly anyway. In other words, it’s more than setting a frequency and an offset (and maybe a PL). You must program your own call into the “MYCALL” field, and call of the station you are trying to contact into “URCALL” (or CQCQCQ for any), and the call of the repeater you are using into “RPT1″…at the very least. More on these settings later. When you transmit, your callsign is also transmitted, and will be displayed on the screens of all radios receiving your signal. That means that your radio is ID’ing for you…so you really don’t have to.
Once the settings were finally set correctly, I was into a local D-Star repeater that is currently set up about a mile from me. It’s not linked to a gateway (yet), but it’s up for us early adopters to learn how the system works. I quickly learned that a strong signal is not required to get clear audio. As you would expect from a digital system, there’s no static. You’re either there, or you’re not there…there’s very little gray area (and that’s where the digital “warbling” comes in). To prove the weak signal effectiveness, I was in Tampa, and worked a repeater in Lakeland, about 35 miles away. Where the analog signal would have been weak and scratchy, the received audio on D-Star was crisp, clear, and full-quieting…although the received audio does have the unmistakable, yet hard to describe, digital audio quality to it.
D-Star repeaters are able to be Internet-linked, but they do have their limits. In order for repeaters to get access to the gateway, they must possess a club call, and not an individual call. This may be attributed to the repeater rules in D-Star’s home country, Japan, where no repeater can operate under an individual’s callsign. That means that if you want to be linked, you need to get a couple of friends together, get a club license, then tie-in to the gateway.
Repeater callsigns are broken up into smaller ID’s, to indicate band or function. CALLSIGN_A is 23cm, _B is 440, _C is 2 meter, and _G is the Internet gateway. This information becomes important rather quickly.
Once you _are_ on the gateway, then there’s more to add to the radio to work across the link. Unlike Echolink and IRLP, which use DTMF commands to enable and disable linking, D-Star linking requires another trip to your radio’s menu. Here, you would put the call of the remote station in “URCALL” your local repeater in RPT1, and the repeater gateway in RPT2.
So let’s say FieldComm had set up a D-Star machine on 440 with an Internet gateway, and I wanted to reach Jay across it. My radio would be set like this: MYCALL: KD4ACG URCALL: KD4BPZ RPT1: MYLOCAL_B (where MYLOCAL is the callsign of the repeater in my area) RPT2: MYLOCAL_G (where MYLOCAL is the callsign of the gateway in my area)
Notice that I don’t need to know the callsign of the repeater that Jay is on. The Internet gateway will determine that for me, based on where Jay was last heard. Optionally, if I wanted to reach anyone on WA4FC, I would replace Jay’s call with “/WA4FC_B” in the URCALL field.
Make sense yet? Yeah, it’s a little tricky until you start using it. And then it’s still a little confusing.
This design creates a limitation: Unlike analog repeaters, D-Star machines cannot be linked and simulcast 24/7. They are linked on-demand, and that’s it. In areas where linking is widely used, it may hamper D-Star’s growth.
Another limitation: Repeater control ops cannot remotely turn the repeater on and off. There is no DTMF access to the machine. This has been an area of concern for the FCC. There’s no word yet whether this can be fixed, or if the FCC will bend the rules for digital repeaters.
While there seems to be no interest in Central Virginia at this time, D-Star is expected to see growth in many parts of the country in 2008, including here in the Tampa Bay area. The current “experimental” repeater in my area, will move to 200 feet, get a club callsign, and access to the gateway. In addition, the West Central Florida Group (which runs the massive NI4CE network) has coordination for D-Star on it’s 805-foot platform just south of Tampa. An analog repeater at that height has fringe HT coverage to almost 40 miles out. So a digital repeater at that same site is expected to have at least the same reach, if not more. All that stands between us and the repeater going on the air, is about $1500 more to purchase the gear. The rest of the infrastructure is already in place.
It will be interesting to see how much growth D-Star sees in 2008, now that both repeater owners and operators are beginning to invest in gear. Its feature limitations versus analog, and its initial difficulty to program, are likely the two biggest barriers, aside from cost. We’ll see how easily those are overcome.
Stay tuned for more as I delve deeper into the world of D-Star.
