Article: 50975 of rec.radio.amateur.digital.misc From: "Charles Brabham" Subject: PC as a TNC Message-ID: Date: Tue, 26 Jul 2005 08:58:56 GMT This year I've had a hard time keeping a TNC on my HF Packet BBS... First a lightning strike took out the entire station and once I had rebuilt or replaced all that, the TNC I got for HF didn't work very well. I never did track down what the problem was with that TNC, but I could tell that the TNC was the problem because I could hook up the same radio/antenna setup to my hamshack computer running MixW in 300 baud Packet mode and it would perform just fine. Then one day I was browsing the various menus in MixW and realized that it was capable of emulating a KISS TNC if you could give it a second COM port to use in addition to the one used for the soundcard interface. - I hooked up a null-modem and cable to that port, and had a virtual KISS TNC. - I hooked it up to my BBS computer's COM port where the HF TNC was supposed to go, and it worked perfectly. The BBS now had a good TNC for HF and immediately started transferring messages with other stations in the ARRL SkipNet. "Hey that's great!" I thought. I figured that it would do as a temporary fix until I could get my TNC straightened out. - I would run the BBS software on the old DOS PC, and have MixW on the "Winders" computer, emulating an HF Packet TNC. ( The BBS computer also has a TNC hooked up for VHF, but that works fine and so does not get more mention than this. ) It turned out that I was very wrong about that, and I had my nose rubbed into it within minutes of getting the new setup going... I looked up at the MixW display, saw that I was slightly off-frequency, clicked the mouse and set my station exactly upon the one it was communicating with in a lot less time that it takes to describe the action. Anybody who has ever tuned in an HF Packet signal 'the hard way' without a waterfall display knows how radical an improvement this is... Instead of endlessly twisting the dial and pursing my lips in the hope that I would accidently end up on frequency with the other HF Packet station and settling for just about any level of communication at all, now I could just point 'n click for instant accuracy and assurance in tuning. After using a waterfall display to tune HF Packet, anything else is comparable to fumbling around in the dark. I was already spoiled... It took less than an hour. It was ( and is ) great to be able to see and identify nearby and interfering signals instead of just wondering why the link was suddenly slow. Now I can sit back and watch PACTOR III stations come in right on top of an ongoing Packet net just about any evening. - It literally happens every day, something I had not been aware of before. Those PACTOR III lids have got to go. - They are not fit company for thier fellow hams onair, where it matters the most. Then I read about a new release of the Q15x25 mode dll package for MixW, and how the new modem was scalable... That is, if you set the modem for 1200 baud instead of the default 2500 baud, the modem would scale the signal down to half of the previous bandwidth. MixW considers Q15x25 to be a "Packet modem" even though it really uses PSK tones instead of Packet. At any rate, the end result is that switching my BBS from HF Packet to Q15x25 mode now just takes - a mouse click. That was it! I put the cover back on the old HF TNC and tossed it into the junk box. If you are a Packet BBS SYSOP on HF or are thinking about becoming one, do yourself a favor and check this out. - You'll be very glad you did. Obsolete Win98 machines work fine for this application, and in many places can be had for much less than the price of a new HF-capable TNC. Once you try it, you'll never go back. Charles Brabham, N5PVL Director: USPacket http://www.uspacket.org Admin: HamBlog.Com http://www.hamblog.com Webmaster: HamPoll.Com http://www.hampoll.com