mikey@trsvax.UUCP (06/08/84)
#N:trsvax:52800019:000:955 trsvax!mikey Jun 8 09:18:00 1984 I'm about to design a RTTY card for my Coco. I'm having no trouble designing it for 170 hz shift. However, I want to make it so that it will also function on 425 and 850 hz shifts that I've heard are used commercially in the HF bands. I'm using an Exar 2211 as the demodulator. Since the 2211 can be tailored for different data rates and such, I need to know what speeds are used. I'm new to RTTY and the only thing I know is that hams on VHF generally use 110 baud in the Dallas/Ft. Worth area with 170 hz shift. I was also going to use overlaping switched capacitor filters to give me a variable bandwidth filter, but I don't know if the filter is even necesary on VHF. If it isn't, it will be added later, as my primary goal is to get up a monitor on VHF first, then get transmitting ability on VHF, and then start on the other bands. I don't know what is necessary at this stage of the game. Any suggestions? mikey at trsvax KA5MJQ