Oh boy, oh boy. Your the one that indicated multiple QSO's on the same channel on HF were possible with TDM/CDM, in fact that's why they were invented.
The channel bandwidth of GSM is exactly relevant to this discussion. You have to know the RF bandwidth per user in order to make an intelligent decision about using the technology at HF. That is unless you have reason to believe that you can transmit more data in a smaller RF bandwidth at HF than you can at UHF. The other problem with your scenario is operational. For example, lets just assume you can get 20 qso's in 100 kHz. And you set up the channel from 14250 to 14350. Either you have the FCC dedicate that channel for that purpose, or you have to share. If you share, one SSB qso in that space would prevent 20 other qso's from happening. The biggest problem is how to accomplish upgrading hardware and software when new developments come along. You won't be able to use your handy dandy HF tranceiver for a bandwidth like this, and forget computer sound cards with a 100 kHz bandwidth. Now everyone spends their hard earned money (and expect it to cost quite a bit)to get setup and guess what, 6 months later someone comes along and says, hey, I can now get 23 users into that same space and since my method is newer and better, my method wins! But, if you want to use it, you have to buy new hardware and software! That will go over real big won't it. I don't know what you think spread spectrum will buy you in a "standard" HF channel. You can only get enough data through that standard channel for one conversation to occur. Normally one would estimate the total bandwidth required by multiplying the bandwidth per user by the number of users you want on that channel. That's because you have to send the same amount of data per user only quicker so you don't get delays or latency. If you try to add a second conversation in a bandwidth designed for one conversation, your going to have long delays while the other station sends. And in fact, it could be two other stations sending if there are two parties per qso. You may not mind the stuttering sound but I sure would. Ultimately, you have to decide if the spectrum, technical, and economic efficiencies are any greater with a system like this versus plain old SSB or DV in a SSB channel! It is not evident to me that this will be the case. Jim WA0LYK --- In digitalradio@yahoogroups.com, "Dr. Howard S. White" <[EMAIL PROTECTED]> wrote: > > The commercial GSM numbers are not relevant to this discussion ..we are talking about Ham radio which has different design parameters... > > Using spread spectrum for example it should be possible have multiple QSO's in a standard HF voice channel.... > > More important, if we design systems to maximize band utilization we should be able to carry many more QRM free QSO's on our current bands....which would have the benefit of not only curing current overcrowding but also virtually eliminate annoying QRM.... > > So rather than sowing seeds of fear of the unknown... we, especially on this digital reflector.... should be embracing the new technologies... > > The technologies are out there just waiting for some clever hams to implement them...... > > The point I am making is that we need to have rules that allow us to be able to experiment...on HF... as well as VHF/UHF... > > __________________________________________________________ > Howard S. White Ph.D. P. Eng., VE3GFW/K6 ex-AE6SM KY6LA > Website: www.ky6la.com > "No Good Deed Goes Unpunished" > "Ham Antennas Save Lives - Katrina, 2003 San Diego Fires, 911" > ----- Original Message ----- > From: jgorman01 > To: digitalradio@yahoogroups.com > Sent: Thursday, February 02, 2006 8:39 PM > Subject: [digitalradio] Re: ARRL proposal removes baud rate limitations on HF > > > I am assuming your comments were meant to be applicable to the HF > bands since there is nothing to stop hams from doing it on the higher > UHF bands. > > For educational purposes, would you share with the group the RF > bandwidths used for the "shared channels" you are talking about and > how many conversations that channel can carry. That way everyone can > decide how applicable the technology would be on the HF bands. > Perhaps the GSM/TDMA channel bandwidths and capacity would be best. > > Jim > WA0LYK > > --- In digitalradio@yahoogroups.com, "Dr. Howard S. White" > <drpaper@> wrote: > > > > Cingular, AT&T use GSM which is a form of TDMA for their Cellular > Systems. > > __________________________________________________________ > > Howard S. White Ph.D. P. Eng., VE3GFW/K6 ex-AE6SM KY6LA > > Website: www.ky6la.com > > "No Good Deed Goes Unpunished" > > "Ham Antennas Save Lives - Katrina, 2003 San Diego Fires, 911" > > ----- Original Message ----- > > From: F.R. Ashley > > To: digitalradio@yahoogroups.com > > Sent: Thursday, February 02, 2006 3:14 PM > > Subject: Re: [digitalradio] ARRL proposal removes baud rate > limitations on HF > > > > > > > > ----- Original Message ----- > > From: Dr. Howard S. White > > To: digitalradio@yahoogroups.com > > Sent: Thursday, February 02, 2006 5:28 PM > > Subject: Re: [digitalradio] ARRL proposal removes baud rate > limitations on HF > > > > > > Which is why they developed Time Division Multiplexing and Code > Division Multiplexing ... so that multiple QSO's can share the same > channel.... > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > Howard, > > > > Its been quite a while since I've heard someone mention Time > Division Multiplex. Have you ever heard a TDM signal? Years ago, I > tried unsuccessfully to find some TDM signals and copy them. If my > memory serves me correctly, weren't TDM signals transmitted almost > continuously, but most of the time containing no data, just a carrier? > Also, I cannot remember who used TDM, can you refresh my memory? > > > > 73 Buddy WB4M > > > > > > > > > > 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 > > > > a.. Visit your group "digitalradio" on the web. > > > > b.. To unsubscribe from this group, send an email to: > > [EMAIL PROTECTED] > > > > c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service. > > > > > > > ------------------------------------------------------------------------------ > > > > > > > > > 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) > > > > > > SPONSORED LINKS Ham radio Craft hobby Hobby and craft supply > Icom ham radio Yaesu ham radio > > > ------------------------------------------------------------------------------ > YAHOO! GROUPS LINKS > > a.. Visit your group "digitalradio" on the web. > > b.. To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. > > > ------------------------------------------------------------------------------ > 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! 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