[amsat-bb] Re: Email via Satellite Simulated Emergency Test

[Nate Duehr]

On Nov 5, 2007, at 3:26 PM, Bob Stewart wrote:

> Bob can you or anyone tell me if there are software TNCs  for
> soundcards out there?  I know almost nothing about APRS or
> even where to turn to get useful information.  Unfortunately,
> buying a TNC is simply not going to happen at this time.  I am
> a Linux user.


Bob,

In the "early" days of packet radio, TNC's or "Terminal Node  
Controllers" were often used because the PC's themselves had little or  
no soundcard support, and most folks were comfortable with external  
modems for calling BBS's, and later dialing into the early Internet.

TNC's are still available for specialized functions like acting as  
standalone digipeaters (a TNC and a radio on a mountain, no computer  
required), etc... and some people still like them for other reasons...  
but they're FAR more expensive than software on a PC, a sound card,  
and a simple audio and keying interface to the rig, nowadays.

Too bad most of the "official" books from ARRL and others on the  
subject still have 1980's black and white photos of TNC's to guide the  
new hams doing this stuff off into oblivion.

But most "modern" digital setups include at least one connection from  
the sound card of a modern PC to a radio directly or via one of the  
many interface "boxes", which are just a nicer way to package up all  
the connectors and possibly some isolation electronics to isolate the  
PC (an excellent RF noise generator) from the rig, and also to provide  
simpler "plug and play" connections for things like keying logic from  
the PC to the rig.

The TigerTronics website has a good listing of a whole bunch of  
software that will work with soundcards, for example, since they sell  
one of these interfaces.  (A pretty good one too.  They also sell the  
TigerTronics Signalink USB which contains a USB-based sound chipset  
that "looks" like a secondary sound card to the PC, which has a VOX  
circuit for keying).

http://www.tigertronics.com/sl_soft.htm

There's a LOT of ways and a LOT of software out there for the various  
digital modes that will work with a sound card, a simple audio  
interface and some way for the PC to key the rig.  Almost too many to  
describe all the options.

What kind of rig do you have Bob?  Perhaps the group can tell you the  
easiest and cheapest way to get it going for APRS.  Some software is  
free, other software costs a few bucks, but it's far cheaper than  
anything using a real TNC will be.

--
Nate Duehr, WY0X
nate at natetech.com