GETTING INTO DIGITAL COMMUNICATIONS

A primer from K8BE - "Whitey", and Carolyn - N8ST

       This eBook is meant to be a starting point for the ever increasing number of people wanting to get into amateur radio digital modes of communication. I hope this makes getting started in Digital a glad and easy experience. Even if interfacing using other manufacturers interface devices other than from Donner's Digital, most setup procedures are similar, so this material should still be useful.

Computer Requirements: 
             For modes other than SSTV, it is recommended to use a PC that runs at a minimal speed of 100 Mhz. Some success has been attained as slow as 75 Mhz, but that gives little or no margin of  resource.  Memory recommendation is 32 megs or more. Your best bet is a 300 Mhz (or faster) machine, with 64 megs (or more) of ram. The PC needs at very least, a 16 bit Sound card, ie: SoundBlaster Pro.  Please note that some softwares for digital communications use a direct access to the sound card hardware, and in some instances, Soundblaster "compatible" cards may not work. It is always best to use a Creative Labs Soundblaster card (Pro, 16, 32 AWE, 64 AWE) when possible. A "compatible" card will work usually; but it depends on the software being used. Some programs will work with most cards, but keep in mind that if you have problems, you may need a genuine Creative Labs card.
Always install the latest driver available, since older drivers might contain bugs.  Some programs which run under 32 bit operating systems may require a 32 bit sound card driver. Some drivers for Windows 95/98 may actually be a 16 bit driver instead of the 32 bit driver that you need.
    Having tried several types/brands of sound cards here, we have had best results using an inexpensive Crystal Fusion card, which is also stable enough for SSTV.  Video is not too demanding unless one wants to operate SSTV, and then all resources need to be faster and stronger.    The PC should have at least 1 free serial port, preferably a DB-9 style connector. 
        We have learned from personal experience, as well as from several of our thousands of customers, that not all computers  lend themselves for digital communications requirements. An example of this is a Dell Inspiron Laptop. A good machine, but the worst choice for digital use. This machine is notorious for the serial port coming up high on startup, and along with that, a serial voltage much lower than standard. There is a software fix to cure the high start, but none for the low port voltage. There have been reports of a few Compaq laptops also having low serial port voltage, but from experience I have only incurred the trouble with the Dell.  When we go mobile/portable, we use an IBM Thinkpad, or a HP laptop. Nearly all desktop computers seem to do the job very well.


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