--- In Repeater-Builder@yahoogroups.com, MCH <m...@...> wrote:
>
> Threaded...
>
> John wrote:
> >
> > Hmmm... I'm sitting here with my NQMHS Node Adapter (GMSK Modem) and
> > watching the binary stream, in both Hex and Char, off of my IC-91AD, while
> > transmitting for a few seconds. It seems the callsign information is
> > repeated on a pretty continuous basis looking at the trace. I think it may
> > just be a repeater/gateway control implementation issue.
>
> Your callsign or the destination callsign? It's the latter that needs to
> be interlaced (well, really the whole header should be interlaced).
>
I am not where I can quickly look at it again, but as I recall it was the
entire header. Without really digging it apart it seems that my GMSK modem was
delivering a longish stream as a series of blocks with the entire header
inserted ahead of each block, whether that is artificial (created by the modem)
or the on-air stream, I can't say for certain, but it seems to be something
that Icom provides in the radio, based on page 3 of this paper
http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=d-star+uncovered
(middle paragraph, "Icom has made use ...".
> It tells me that people:
>
> 1) Don't want to jump aboard the one-source format yet.
>
There are other ways to get on the mode, rather than using the Icom solutions.
Most of them are "home brewed" or a combination of kits. The "format" is open
to anyone to implement.
> 2) Don't want to give up the interoperability of analog.
>
Maximum "interoperability" would be CW, wouldn't it? (Oh, yeah, a lot of hams
don't use CW anymore, time has moved on.)
> 3) Don't want to switch to digital for whatever reason. (else P25 would
> be the format of choice since it's a multi-vendor standard)
>
Multi-vendor and expen$ive if you want new, current generation radios. D-STAR
is cheap by comparison. (Great entrepreneurial opportunities here.)
> And how do I get this $150 D-STAR conversion for my repeater?
>
This is the real issue and question. Once you have a well engineered repeater
(FM), the conversion to D-STAR is relatively simple and cheap.
First the repeater should be true FM (not PM).
You need access to Discriminator, Modulator, and PTT (optionally COR). In many
repeaters these are already brought out to an accessory connector, but can
otherwise be located in the radios.
You add a "Node Adapter" GMSK modem board. There are two main sources:
1) The "Satoshi" board. About US$117 (Assembled board -
http://d-star.dyndns.org) there is some history here and he locks his boards to
the owner's callsign (there is some "bad blood" between him and the next
option).
2) The "G7LTT/NI2O" board (US based) US$80 as a kit, US$110 assembled - it
runs both "Satoshi" firmware and PA4YBR firmware. PA4YBR is obtained for
around US$15 at www.dutch-star.nl -- this is the board/firmware (PA4YBR) that I
have.
These boards have a DB-9 which is used for connection to the repeater and a USB
port used for programming the board parameters and sending the datastream
between the board and software on a computer to talk to the Internet.
Alternatively, there is a sound card based GMSK modem, that uses a Vellman
K8055, Serial port, or URI for PTT/COR by Jonathan Naylor, G4KLX. See
http://groups.yahoo.com/group/pcrepeatercontroller -- BTW, this design includes
a plan for a combined Analog/D-STAR repeater as some here think would be a good
idea.
Each of these adapters (or software) can run as a standalone repeater, or can
communicate with the D-STAR network using additional gateway or hot spot
software. There are a lot of options in this space. Mostly discussed on
http://groups.yahoo.com/group/pcrepeatercontroller and
http://groups.yahoo.com/group/gmsk_dv_node lists. There is also code, soon to
be released, from a project by G4ULF, see http://g4ulf.blogspot.com/
Once you have your board (or G4KLX's soundcard software) it is time to mate it
to the repeater. This involves connecting the respective Disc, Mod, PTT, and
optionally COR lines to the board or soundcard.
Next you will need to adjust the deviation on the repeater transmitter (about
1.9 khz. as I remember YMMV) and the audio levels in and out of the board or
soundcard. Configure parameters; callsign, network connection (if used), and
inversion/non-inversion of transmitted and received signals.
That's pretty much it.
> > I can tell you with certainty that having D-STAR (or most digital voice
> > modes) on the same repeater with analog users is impractical in amateur
> > radio. Many, if not most hams, don't even use CTCSS on their radio's
> > squelch and even if they did the squelch can be falsed by the digital
> > signal. We have a D-STAR repeater in the Seattle area (atop a 42 story
> > building) and it is on a Shared Non-Protected pair on 2 meters. The sync
> > pattern at the beginning of transmissions will open the squelch on CTCSS
> > squelched radios (100 hz.) at 60+ miles away (for users of another FM only
> > SNP repeater in Port Angeles). Listening to the structured "noise" of a
> > GMSK digital signal on your analog radio is not an activity one would want
> > to undertake for any extended period.
>
> Just with 100.0 Hz CTCSS or with any CTCSS? If just the one, it sounds
> like an incompatibility like 131.8 and 136.5 is with CDCSS.
>
No exhaustive testing, but the 100hz case is what we have dealt with here.
> And as for having both, that may be reason #4 people are waiting for.
>
> There is no reason why analog and digital cannot coexist. Granted, it
> requires use of CTCSS/CDCSS (perhaps with the exception of 100.0 Hz),
> but it will certainly promote the use of the D-STAR format if they had a
> transition path.
In my view, the better transition path is to repurpose some under utilized
analog repeaters in the same service area and switch between the two depending
on operating mode.
It is my guess that a lot of people who look at P25 or MotoTurbo or NXDN/ICAS
and say having both on a single repeater/frequency is the way to go, may be
forgetting that these "fleet solutions" (with technicians and central
programming and management) don't map well to amateur use. In each case, if
you want to the dual mode, you are generally working with a fleet that is
converting over to the new format with agency dollars, not the piecemeal system
which is amateur radio (a hobby, with individuals setting up and operating
radios). They are very different scenarios with different needs on a day to
day basis and hams have a lot more flexibility and availability of channels
than a fleet/agency solution might have.
>
> Of course, there is also issue #5 - no reasonably priced radios for
> D-STAR. Remember we are talking about people who resist buying a $40
> CTCSS encoder.
>
"Reasonably priced" is a personal judgement and also where in the product
life-cycle one is purchasing. I know my venerable Icom IC-2AT purchased over
25 years ago would cost over $800 in inflation adjusted dollars. It was single
band/single channel (no scanning) set by thumbwheels, no CTCSS, manual +/-
repeater offset (or simplex) but it was leading edge technology for the time
(many radios were still crystal per channel and limited channels). Some people
are content with simple and cheap, many in the D-STAR community are more
excited about exploring different (and sometimes new) technology, mixing data
and voice over an RF data channel, etc.
> Besides, analog is completely interoperable. D-STAR (or any digital
> format) is not. I don't think we should follow the same path that has
> led to communications problems in the commercial world - problems that
> we have to step in and solve when a disaster strikes.
>
> Joe M.
>
Disasters are relatively rare and I would be hard pressed to find an area with
a D-STAR system that wasn't also covered by multiple analog systems - this is
not an all or nothing proposition, the amateur is not putting all of his eggs
in one basket. One of the biggest barriers to D-STAR is getting a repeater pair
because people hang on to them even when they are vastly underutilized.
DE K7VE
