NXDN uses the same codec/modulation as D-STAR, that is why D-STAR DV
is claimed to be 6.25 Khz., the radios may just not be as tight. I
think the Utah VHF Society studies showed that different models of
Icom D-STAR radios exhibited different RF characteristics. http://utahvhfs.org/dstar.html
-- in figure 4 at http://utahvhfs.org/dstar_channel_spacing.html it
says that two D-STAR signals of equal strength can co-exist at 6.25
Khz. spacing.
On Oct 2, 2009, at 2:49 PM, Trevor . wrote:
But commercial systems (NXDN) with mobiles, handhelds and repeaters
that use 6.25 kHz channel spacing have been available for years -
both Icom and Kenwood are active promoters of the system which uses
a far more efficeint modulation techique that D-Star, see
2005 - Icom and Kenwood demo 'Very Narrowband Digital Communications
Technology'
http://www.southgatearc.org/news/apr2005/icom_kenwood_demo.htm
2008 - The Gadget Show tests digital and analog walkie talkies
http://www.southgatearc.org/news/november2008/gadget_show_radio_tests.htm
73 Trevor M5AKA
.
John D. Hays
Amateur Radio Station K7VE
PO Box 1223
Edmonds, WA 98020-1223 VOIP/SIP: [email protected]
Email: [email protected]
