Someone wrote:
Please do not use FM on any of the transponder satellites, whether D-Star or plain FM. FM of any kind is expressly unwelcome on AO-7 especially.
If you would like to set up a test of D-Star via AO-51, please organize the effort and send a request to schedule it to ao51-modes@amsat.org or to myself directly and we will accommodate the test on a FM satellite, where FM belongs. I think it'd be an interesting experiment.
Umm, I thought D-Star was a digital mode, not riding on top of FM. Is it transmitted as AFSK or is it modulated directly onto the carrier? If it's the latter, then it wouldn't work on an FM satellite.
73 de VK3JED http://vkradio.com
From ICOM America web site: D-STAR uses the up-to-date modulation method of 0.5GMSK--Gaussian Minimum Shift Keying.
73, Bob K0NR
At 02:16 PM 2/27/2007, Bob Witte K0NR wrote:
From ICOM America web site: D-STAR uses the up-to-date modulation method of 0.5GMSK--GaussianMinimum Shift Keying.
Which means it won't work through an FM transponder. Would need either a linear transponder or a digital repeater.
73 de VK3JED http://vkradio.com
GMSK... thats the modulation scheme used for GSM cell phone systems isnt'it ?. Admittedly its along time ago since my telecom days but I'm pretty sure that the signal was transmitted as an FM signal. GSM phones sure do work!
Don. ZL1THO
--- Tony Langdon vk3jed@gmail.com wrote:
Which means it won't work through an FM transponder. Would need either a linear transponder or a digital repeater.
Existing guidelines would appear to rule out the use of linear satellites for D-Star due to bandwidth and duty cycle considerations. So it appears the mode can't be used on any existing satellites.
This goes back to the concern I was expressing in my original email. New Amateur Digital Voice modes are being developed without any apparent input from the satellite community. A decade from now we could see Amateurs swapping over completely to Digital Voice certainly on VHF/UHF and very possibly also on HF. If Amateurs cannot use their commercial Digital Voice radios on the satellites we could have a major problem in recruiting new satellite operators.
I note ARRL are seeking comment on the development of a new open-source data communications protocol suitable for HF, see
http://www.arrl.org/news/stories/2007/02/22/102/?nc=1
73 Trevor M5AKA
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At 09:35 AM 2/28/2007, Trevor wrote:
Existing guidelines would appear to rule out the use of linear satellites for D-Star due to bandwidth and duty cycle considerations. So it appears the mode can't be used on any existing satellites.
Guidelines are just that... guidelines. That said, it's certainly best to avoid such high duty cycle modes on the linear birds.
This goes back to the concern I was expressing in my original email. New Amateur Digital Voice modes are being developed without any apparent input from the satellite community. A decade from now we could see Amateurs swapping over completely to Digital Voice certainly on VHF/UHF and very possibly also on HF. If Amateurs cannot use their commercial Digital Voice radios on the satellites we could have a major problem in recruiting new satellite operators.
Well, maybe the satellite community needs to look at what sort of mode would suit it (likely something different to terrestrial comms). The plethora of new modes is another argument for putting more effort into SDR technology. Good to see TAPR working towards that end (unfortunately, their timing is really bad for me and I doubt I'll be able to order the boards while they're available :( ).
73 de VK3JED http://vkradio.com
participants (4)
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Bob Witte K0NR -
don -
Tony Langdon -
Trevor