Jim,
It would be interesting to see how the D-Star modem performs so please
keep us in the loop. From what I gather, the modem for Dave's codec will
not be as narrow as the one used for FDMDV. It will still use Peter's
FDM modem, but the bandwidth will most likely be closer to 2KHz.
Tony -K2MO
On 9/7/2010 3:50 PM, J. Moen wrote:
There are people who probably have the answers to the points you make
since some have already had DX QSOs using D-Star -- I haven't, so I'm
looking to try this out on 10 meters. Mostly I think your prediction
will turn out to be correct. I am expecting that only under
near-perfect conditions between the two parties will D-Star make it
via HF propagation. My experience on VHF is that it's extremely
susceptible to multipath.
On the other hand, during previous sunspot cycles, I've experienced
near-perfect conditions on 10 meters. I definitely would not see the
present D-Star for everyday digital voice on HF, though I can see some
value in a 6 meter repeater, and some 10 meter activity, with callsign
routing, repeater/reflector linking, low speed data, short messages, etc.
10 meters has a lot of real estate, so I would think the wider
bandwidth of D-Star will not be un-neighborly except possibly during a
busy contest. But then, that's true of a lot of modes on HF during
contests.
It will be fun to watch David Lowe's Codec2 project evolve and see how
narrow a bandwidth he can achieve. For everyday DV on HF, that may be
the best path. In the meantime, I'd just like to experiment and learn.
Jim - K6JM
----- Original Message -----
*From:* Tony <mailto:d...@optonline.net>
*To:* digitalradio@yahoogroups.com
<mailto:digitalradio@yahoogroups.com>
*Sent:* Tuesday, September 07, 2010 12:04 PM
*Subject:* Re: [digitalradio] Fwd: [KenwoodTS-2000] D-Star with
the TS-2000
I have to agree that it would be interesting to experiment with
the D-Star modem, but it doesn't seem practical for HF. In
addition to gobbling up a fair amount of spectrum, I suspect that
it would be difficult to maintain the required SNR with a modem
that's 6KHz wide.
The narrow-band FDMDV modem worked out well by not only improving
sensitivity over WinDRM, but by allowing one to "squeeze" the
signal between the adjacent QRM. The modems quick recover time was
a real plus as well - not sure how long it takes for the D-Star
modem to re-sync.
Tony -K2MO
