Even though I am not an engineer, we know from P-25 that digital voice transmissions drop out before analog completely goes into the noise and it is my understanding that the narrowest BW they use is 6.25 KHz. And that is primarily for VHF/UHF frequencies that do not have the problems we have on HF bands.
Since we are not likely going to be able to use wide BW HF signals here in the U.S., I really don't see DV being used that much on HF. It may be used more on the higher bands, but even then there MUST be some advantages to this new technology, other than just being new. Typically, you move toward new technology when it is either faster, lower cost, higher quality, or some combination of these and perhaps other attributes. Digital signals can offer this with text transmission (PSK31, MFSK16, Olivia, etc.) but it may not be able to offer benefits for amateur HF which operates very differently from what a non-technical user does on the commercial/military frequencies. Digital signals are limited by the science behind this technology and we can not change that unless some new breakthrough occurs. 73, Rick, KV9U Ed Hekman wrote: >I work in cellular communications and know that good voice quality >can be maintained with a data rate of 8k bps. It seems reasonable >that useable voice quality can be produced with half that data >rate. Are there any communications engineers in this group that can >give us some idea whether a useable quality digitized voice can be >sent over a 2.5 KHz wide HF channel with SNR comparable to or less >than what is required for analog voice? > > > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
