D-Star contacts in Melbourne

I was in Melbourne for a couple of days this week and was fortunate enough to loan a D-Star equipped handheld from Duncan VK6GHZ for the trip.

I configured the handheld before heading to Melbourne from the instructions on the Australian D-Star website. (Recommended) . I am usually the type that can take a radio straight from the box and start operating it, hardly having to read the user manual. I am afraid that with the D-Star radio this wasn’t possible and I had refer to the manual on more than one occasion! Once the D-Star was setup for the first time I could put the manual away, but there are certainly more functions in it than I was able to use.

I fired up the radio after checking into my accommodation in Kensington (Approx 5kms from the Melbourne CBD) and did some listening around.

Quite a bit of activity was heard on 70cm repeaters and simplex frequencies. QSO’s were also heard on 2m & 6m from around Melbourne.

With a slight bit of trepidation I put a call out on the VK3RWN D-Star repeater. No CW identification, courtesy tone reset pips, unsquelched mute noise or even a reply call came back.

I called on the repeater a second time, listening to the output on my other handheld and could hear the repeater transmitting. I was also looking at the display of the D-Star handheld and watched ‘VK3RWN’ scroll across the display.

The speaker then came alive and VK3BMX responded to my CQ call. His callsign scrolled across the handheld display and we had a short contact. The audio was crisp & clear even on the handheld speaker and sounded slightly ‘nasally’.

The repeater was quite good signal strength even inside the QTH I was staying at. I did some quick experiments with the transceiver horizontal at floor level to get the signal level quite low and the digital audio not decoding cleanly (garbling) or what the locals call ‘R2-D2’.

When using the repeater, a four (4) second gap between transmissions must be left between transmissions for the system to reset (No PTT machine gunners!). This can slowdown a QSO a bit, but according the D-Star gurus this is needed to reset the system correctly after each over.

The D-Star repeater would be quite disconcerting to the local repeater ‘kerchunker’ – No CW idents, no timeout reset pips, unsquelched mute noise or your rig speaker popping open to keep the crowds entertained from this baby. Worse still for the kerchunker is that your callsign scrolls across the screen of everyone that is QRV on the repeater as well as being logged and visible on internet.

From my further observations later, I would estimate that the digital decode became garbled down around what you would expect to hear from a station with a S1-S3 signal level in the analogue FM world. As would be expected, the D-Star didn’t decode down into the noise, but a low signal sounding so clear would certainly be a welcome suprise to most FM users!

The next day I had a couple of more contacts on the VK3RWN repeater to gain an impression of the system. I also took the handheld portable around the streets of Kensington for a brief test. Mobile flutter or picket fencing becomes a thing of the past with D-Star, but garbled decodes and R2-D2 come into play. I guess that where you might lose half a word or a word on mobile flutter, I found on D-Star that it became one or two words until the decode could resume.

I also joined in on a local net one evening where a number of stations discussed D-Star and assisted each other with their D-Star experiences and helping others through problems or issues. I could also see that some operators had their name or the radio they were using in ‘My Info’, but this information is limited to 4 alphanumeric characters.

I also made a few recordings of QSO’s that took place on the repeater to listen to the action. (MP3 format)

QSO 1 (3.9mb)

QSO 2 (2.9MB)

QSO 3 (4.6MB)

QSO 4 (4.6MB)

In summary, it was quite exciting to use this new mode. The communications are exceptionally clear and all the possibilities for sending voice and data over our bands seems endless. I imagine this comes with every new innovation in amateur radio, be it SSB, FM, repeaters, satellites, packet radio, IRLP or Echolink.

The cost of new equipment seems quite reasonable and the add on D-Star capability for some older models is also good to see. Hopefully in time other manufacturers of equipment will also have D-Star equipment available in the market to spurn competition and innovation.

Australia has been very lucky to have Icom & the WIA support the provisioning of D-Star repeaters in several states. Due to the high costs of purchasing and maintaining a D-Star repeater it is unlikely and unfortunate that we will not see use spread outside of the metropolitan areas in the near future.

73’s

Rob…

VK6JRC

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