Saturday, April 21, 2012

D-STAR: New DCS reflectors and DV-RPTR boards

When I was playing around with D-STAR last weekend, I thought the REF001C and REF005A reflectors seemed a bit quiet. I wondered whether people had got fed up and moved on. I didn't worry too much as I had some nice QSOs.

During the week, I noticed a tweet from the Bromley Repeater Group saying that they had connected up MB6SS, one of their nodes so that they could access the new DCS reflectors. I'd seen a comment about DCS reflectors when I had installed the new version of Win-DV, but hadn't had a chance to investigate.

A quick Google provided some useful information and I found the following from Kurt DJ0ABR, 'The main difference (and the advantage) of DCS compared to old reflectors is, that is does not more use the Header-Voice separation. The separate transmission of headers and voice packets makes sense on RF due to the limited bandwidth. But it causes many routing problems in old reflectors. DCS uses a new format and transmits (over the internet) the routing information with every single voice packet. This makes routing much more reliable. Protocol wise there is no header packet, instead each AMBE packet includes a header which adds a lot of resilience and allows you to pick up a QSO mid over. Operation wise: The main differences are that DCS reflectors use channels A to Z and they have names, DCS001 A is world wide, and is permanently linked to the A channels on all other DCS reflectors. A nice touch. The new client code is implemented already in Jonathans gateways, in the Control Center and in a couple of Icom clients. DCS was invented and developed in February by DG1HT, Torsten. I am helping him in debugging and testing. DCS001 runs at a gigabit intenet node in a high school and is currently designed for up to 700 simultaneous QSOs.'

Very interesting. So I did a little research and found that DCS005B was the main UK reflector, though I can see that they are some regional reflectors, for example DCS005W for Wales and the West and DCS005L for the London area. In practice, the new reflectors work well and seem to provide better audio quality than the old-style 'REF' reflectors. It's also nice that you can pick up a QSO half way through an over rather than having to wait for the start of the next transmission.

Activity on the new reflectors can be seen at http://xreflector.net/neu3/ Also, have a look at the DV-RPTR boards which should provide a cheap route for more people to get involved with D-STAR with their existing equipment. This all seems like a positive step in the evolution of D-STAR and pleasing that it is progressing in a more open direction.

1 comment:

Anonymous said...

Informative article, Tim. I also find the DCS reflectors far more robust: You won't get 'bumped' off your QSO by someone the other side of the world keying up to 'ping' a local repeater. When the mobile station you're working drops out from the repeater a couple of seconds, it is re-acquired and the QSO continues. This is how D-STAR should always have been. The experience pre-DCS has been disheartening, as the Ebay graveyard of second hand D-STAR rigs testifies.

The sterling work of the DCS developers in Germany, also associated with the DV-RPTR project is done entirely voluntarily and not for profit. I hope they are able to continue and are aware of our gratitude.

Rob MW0DNK

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