Tony, How it happened in the HDTV world is the transmitting stations pay huge royalties for the IP. You do not see any CH3 adapters for HDTV. Separate royalties are required for video and sound and no provisions, for Amateur Radio experimentation using HDTV has been made.
Amateur Radio is a DIY, learn by doing hobby that also provide services to the public. We have no revenue stream to pay for equipment royalties.
D-Star Codec royalties are with in reach ($22.00 for a codec) and it is an open protocol. It has multipath and synchronization problems. Amateurs are currently experimenting with D-Star HB modem/controllers and radio equipment. As with D-Star home brewing will need to transition from individual to group efforts for new projects.
Satellites will play an increasing role in digital communications as multipath can be dealt with effectively using circular polarization and directive antennas. Most digital systems are not very multipath friendly.
Amateur Radio weak Signal work and contesting most likely will remain with the basic modulation systems. High Power density digital modulation signals do not work well when there are weak or multiple signals present.
The AM aircraft band is still with us. The digital world still has not given us a reliable system to allow for the hearing of a beat telling the A/C controller there is a weak station present as well as copy the stronger signal without asking the stronger signal for a repeat.
Art, KC6UQH -----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Tony Langdon Sent: Saturday, April 23, 2011 2:33 PM To: Gregg Wonderly; Gordon JC Pearce Cc: amsat-bb@amsat.org Subject: [amsat-bb] Re: Icom D-Star
At 01:42 AM 4/24/2011, Gregg Wonderly wrote:
In the end, digital compression of spectrum space is going to happen more
and
more. AM style broadcast is hugely inefficient even though it is painfully simple to do. I don't really believe that D-Star is the right choice for "everything" because it is single source. But, so is Microsoft windows,
There's no "one size fits all. D-STAR has its place, and being the new kid on the block, it's open to a lot of tinkering.
MacOS-X, and many other software based systems. If you are an FPGA programmer, perhaps you can build an FPGA based CODEC for amateur radio that would do voice compression etc. But in the end, you also have to have an transmitter with the appropriate bandwidth output to reduce the spectrum used.
Well, maybe one day someone will package something like Codec2 into a chip. That will be a good day for ham radio, BUT it'll never make D-STAR. Why? Because it's not in the spec and will break the existing installed hardware base. However, the future is likely to consist of "multimode" radios, which can handle multiple codecs and protocols, and which will be capable of having a yet unknown cocecs installed in the field. Also, eventually the DVSI patent will run out, just like the patent for SSB did many years ago.
The simple fact is that HAM radio emission standards (simple voice
modulated
with some simple emission standard) are now more than a century old. As
Not quite. CW certainly is, AM is around the century mark, I think SSB is a little over 80 years old from its first conception, and FM is 75 years old. :)
capable as they are, the abilities they present seem minimal to some. I think that there are great things about them because they do allow long distance communications which the HAM community regularly uses to support distant operations which provide aid to areas struck by natural disaster.
I think this is one area where ham radio will be increasingly important. Alongside the newer modes, it can also be a living "museum" where older modes can live on. The only mode that hasn't survived is spark gap Morse, because it's so spectrally inefficient it became illegal. So ham radio, while it still does advance the art also preserves the art as well, and both are important functions to me. If something happened that required falling back to older analog modes, there's a pool of experienced operators on hand, who know he quirks that the commercial world will forget.
But, we all have to understand that it costs money to do anything "new and different". People experimenting with stuff is great, but it minimizes who can participate if you have to "build it" or "pay a lot". That's just life in general. You can't participate in everything unless you have the resources to do that.
And there's experimentation. I don't have the background and resources to play at a low hardware or software level, but at a higher level, equivalent to "mashups" on the Internet I have played and still do.
In the US, any digital communications that is coded in some way only needs
to
have a publicly visible document detailing how it works for the FCC regulations to be met. Other places in the world may have different requirements and that's nothing new is it?
Requirements here are much the same as the US, somewhat more liberal when it comes to modulation and coding. Basically there are two things that matter. (1) Not to exceed the maximum necessary bandwidth (D-STAR fits on all bands except 2200m), and (2) The coding must not be for the purpose of "obscuring the meaning of the message". D-STAR certainly fits, because radios are readily available, and they don't need encryption keys.
73 de VK3JED / VK3IRL http://vkradio.com
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