--- In digitalradio@yahoogroups.com, "Zack" <[EMAIL PROTECTED]> wrote: > > Thanks for the replies. I thought that there wa something different > about RTTY. > > Zack > Hi Zak,
For RTTY whoever uses the American Tones (Mark 2125Hz - Space 2295Hz) always uses LSB, whereus if you used the European Tones (Space 1275Hz - Mark 1445Hz) you have to use USB so that the 2 systems are compatible to each other. All my old homemade terminal units were using the European Tones so I always used USB. I always favoured the European Tones because they were chosen more wisely to be in the center of the passband of the crystal filter of the old transceivers that only had an SSB crystal filter and also because I liked to listen to the sound around 1360 Hz (the center of the European Tones) while tuning and and afterwards during the QSO. It is a more natural sound to me. Whenever I heard the higher tones that the american terminal units used, I always ended up with a headache. Of course f you did not follow this norm, you could always switch your tones the other way around with the REVERSE SWITCH that all terminals used to have incase someone was not using the correct combination. Is you notice at the tones I described in the first paragraph, the Americans tones are Mark-Space where the Europeans always are Space-Mark. Now with the soundcard programs usually they tell you to use 1500 HZ as a center frequency and use USB. Of course if everybody follows this protocol there is no problem. Some soundcard programs have a SOFTWARE REVERSE SWITCH so that you can change it in case there is any incompatibility in the tone pairs. 73 de Demetre SV1UY
