[OZAPRS] Gating DPRS to APRS

Zik Saleeba zik at zikzak.net
Wed Sep 19 08:22:51 EST 2007


Some corrections on Darryl's points:

1) "It is not an Amateur Radio". This is completely incorrect. It was
developed by Japanese amateurs for amateurs. It's not intended for any
other use. I don't know where he got this from.

2) (Paraphrasing) "The IP on the vocoder is closed". This is true.
However the vocoder chip is available and cheap so it's not a big
deal. There's nothing stopping amateurs from making homebrew D-STAR
radios. Some already have. The downside is that a closed vocoder
algorithm is annoying for people working on SDR. Various amateurs are
working on alternative vocoders so I expect this irritation to go
away. The standard vocoder is excellent so I can understand JARL's
choice.

The rest of his points come down to "I'd have implemented the
technical side differently". That's fine. I'm sure we'd all have come
up with something different from each other. But in the meantime some
smart guys in Japan came up with a great system and it's out there and
people are using it. If you think you can improve on it why not make
your own improved system and encourage people to adopt it?

Here's some great stuff about D-STAR:

a) If you want to know who you're talking to you can just check your
display - callsigns are automatically sent with each transmission
along with GPS location and various other information. It's like APRS
except it plays nicely with voice. All you APRS people would love
D-STAR.

b) It uses only about 8kHz bandwidth rather than 16+kHz for analog FM.
In Japan where the airwaves are packed this is big news. Here it's
handy because it means we can potentially  slot D-STAR repeaters in
between the FM repeaters making twice as many repeaters available.
(I'm not sure about elsewhere but in Melbourne I'm told we're out of
2m repeater slots)

c) My experiments so far indicate that D-STAR works significantly
better in marginal signal situations than analog FM. I've had several
digital QSOs now in situations where analog FM was unusable.

d) The data service isn't here yet but it will give us mobile internet
capability with decent bandwidth. It's much better than anything of
this kind readily available to amateurs right now.

e) There are other nice features like repeater linking being supported
on all repeaters, easy one-on-one QSOs with digital squelch, etc.

Cheers,
Zik

On 9/19/07, Darryl Smith <Darryl at radio-active.net.au> wrote:
> People
>
> Since the subject of the D-Star has been brought up, I thought I would
> reiterate my view of this radio. I will write a review of the D-Star but
> since the WIA seems to be getting some support from ICOM I doubt that a
> negative review would be accepted from a non-member for publication.
>
> Anyway there are a number of reasons why people should stay away from
the
> D-Star.
>
> But before I start I should mention that I attended the US release of
this
> radio, and attended a focus group on the radio at the request of ICOM. I
> know a heap about the radio and the technology inside it.
>
> 1. It is not an Amateur Radio. It is a professional radio operating on
HAM
> BANDS. It is targeted at groups like the AMERICAN RED CROSS, Doctors
without
> Borders, etc. Basically NGO's (Non-Government Organizations) for use
where
> they do not have access to phones. You can see this by looking at the
> repeater system, and imagine the cost.
>
> 2. The VOCODER is AMBE2000. The IP on this is VERY closed. There is a
page
> on Wikipedia on it, suggesting that licensing starts at US$100,000. And
they
> specifically PROHIBIT any PC implementation of the VOCODER. Therefore
there
> is no use for using a software defined radio with this VOCODER since it
> would be against licensing. It is not open at all. They made the
previous
> chip - the AMBE1000 obsolete without a compatible replacement being
> available. I suspect one of the reasons was so that the AMBE2000 would
be
> single sourced with patent protection for longer.
>
> 3. Digital voice is restricted to the narrow band operation. It cannot
be
> used on the 128 kbps channel. What would be good with this radio would
have
> been to have a 50% TX/RX duty cycle where each end could get 64 kpbs
data.
> Well, more like 52 kbps with guard tone timings. Then Allocate 4 kbps
for
> digital voice and you could have had full duplex voice and 48 kbps data
each
> way. How cool would that have been?
>
> 4. The D-1 radio is brain dead. It has an Ethernet port for Data, but
any
> control needs to be done by USB. I know why this is done - simply
because
> you can then use the D-1 as an Ethernet bridge. But it is dumb.
>
> 5. The repeater has a different protocol for interconnects than the data
> connecting to the repeater. One of them is ATM, and I think the other is
IP
> or Ethernet. Making things so different really does not make sense.
>
> Sure, this does have some interesting features, and is extending the
state
> of the art. But It is the platypus of radios. It has been put together
with
> bits and pieces, and although it looks cute, it really is a strange
beast!
> Having said all this, if someone from Icom wants to give me a radio to
play
> with I would be happy to give them a more detailed analysis...
>
> Darryl
>
> -----Original Message-----
> From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On
> Behalf Of Richard Hoskin
> Sent: Wednesday, 19 September 2007 6:17 AM
> To: 'VK / ZL APRS Users'
> Subject: Re: [OZAPRS] Gating DPRS to APRS
>
>
> Zik
>
> Work is underway by The WIA's National D-Star Team to build a DPRS to
APRS
> Gateway for VK3.
>
> There will be an announcement and more details soon.
>
> Cheers
> Richard
> VK3JFK
>
> > -----Original Message-----
> > From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au]
On
> > Behalf Of Zik Saleeba
> > Sent: Monday, 17 September 2007 8:54 AM
> > To: VK / ZL APRS Users
> > Subject: [OZAPRS] Gating DPRS to APRS
> >
> > Does anyone what what plans if any there are to gate posit data from
> > the D-STAR DPRS network to the APRS network? I have a brand spanking
> > new D-STAR rig and would like to track it using my existing APRS
> > tools.
> >
> > Cheers,
> > Zik VK3MHZ
> > _______________________________________________
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> > Ozaprs at aprs.net.au
> > http://aprs.net.au/mailman/listinfo/ozaprs
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