D-star on HF works, I already tested with a IC-7100. Of course it could
be considered a "wideband" HF mode, as it uses > 6 kHz of bandwidth. The
sad part is that the same IC-7100 does not support such wide bandwidth
in "standard" SSB mode. Anyway, freedv with LPCNet is way ahead in time,
using a much more advanced modem (and smaller bandwidth) and a
state-of-the-art AI-based vocoder.
Rafael
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On 10/16/21 5:01 PM, Tom, wb6b wrote:
Hi,
This is all interesting information. I'm back in the reading mode
exploring the things that have come up in the posts.?
One would think that "advanced multi-band excitation coding" (AMBE)
being invented so long ago would be easily improved upon. But,
sometimes the fundamental design is well done and not a compromise
that was realizable with the technology of the time (circa 1990), that
it stands the test of time. Certainly would not need the expensive
custom codec chips; now that it can be implemented in software on
current microprocessor chips.?
One thing that occurred to me might be a sort of "earth-to-mars" mode.
Where each operator's voice, in a conversation, is stored/buffered and
sent at a significantly lower bit rate to the destination. This could
allow for having voice conversations under significantly reduced
signal to noise ratios, facilitating better DX communication. Albeit
with a turnaround delay for each side to pick up on their side of the
conversation. Maybe would give each side some time to think a bit
before they start speaking again to reply. Would also produce sort of
an intriguing feeling of suspense, waiting for the data stream, in the
noise, to end so you can listen the reply from the distant other
location.?
So are the folks experimenting with D-Star on HF just kind of flying
under the radar?
Tom, wb6b
