Mark, Although mark as upper frequency was common in the U.S. and probably other areas, it was not universal as I mentioned with the EU "reversed" low tones. If they were using commonly available AFSK generators, and operating "normal" tone position with the mark AF frequency low, they would almost have to be operating USB.
It is possible that some AFSK tone generators were designed opposite but my source here says that all AFSK units he has known about always had the AF mark tone low. If their tone generator could switch the tone positions, then they could run any tone in either position. In almost all cases, the TU (Terminal Unit) which demodulates the signal could switch to "reverse." The reason that sound card modes may use USB is to make it simpler for the operator. Even if you are using USB, the tones are injected differently depending upon which mode you are on. It is much easier to have the software figure that out for you than to remember which sideband to switch to for a given mode. Personally, I like the fact that an injected tone that is higher than another tone, comes out as a higher tone in RF frequency as well as the input AF frequency. The dial frequencies should be similar if you are using AFSK with "normal" tones on both ends with the same shift and 2125 as the AF mark low frequency. Of course if one operator is using AFSK low tones or FSK, then you will see different dial frequencies on their dial. When using FSK, not all rigs read the same either since it depends upon their design. 73, Rick, KV9U Mark Miller wrote: >The EU example is different from what we have been discussing. The >EU stations are transmitting Mark as the lower RF frequency. We have >been talking about transmitting the Mark as the upper RF frequency >and using USB. This is what MixW allows. If it was possible with >the older equipment, I wonder why USB never caught on until the sound >card modes? Maybe it was not to confuse folks who incorrectly report >the dial frequency for RTTY contacts instead of the Mark frequency. >73, >Mark N5RFX > > > 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/
