[aprssig] TNC vs AGWPE

Andrew Rich vk4tec at tech-software.net
Tue Apr 18 03:53:31 CDT 2006

What the ?

1) I use the 9600 out because it is a set level and no de-empasised FM
2) My home station tracks for doppler
3) Yes my laptop has mic in only - maybe that could be an issue.

Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec at tech-software.net
web: http://www.tech-software.net

  -----Original Message-----
  From: John Habbinga [mailto:kc5zrq at gmail.com]
  Sent: Tuesday, 18 April 2006 6:40 PM
  To: vk4tec at tech-software.net; TAPR APRS Mailing List
  Subject: Re: [aprssig] TNC vs AGWPE

  Don't use the "9600" out.  As far as I know, the ISS uses 1200 baud.

  I'm not sure that I understand.  With your D700 you adjust the frequency
to compensate for the doppler effect and you can decode packets.  Your
system at home, where you don't adjust the frequency to compensate for the
dopple effect, you can't decode packets.

  When you ask about the performance of AGWPE, I assume your talking about
the soundcard TNC feature, just one small part of what AGWPE does.  The most
important part is that your audio levels are correct and that no ground
loops exist.  This means that the computer, the radio and soundcard
interface all share a common ground.

  Laptops usually have a microphone input and a headphone output, but not a
line-in.  I have learned from exerience that sometimes, even when you
manually set the audio levels, the microphone input tries to automatically
compensate for loud sounds.  This "ALC" usually can't be disabled.  You
might try a desktop computer with a line level input or get an external
soundblaster for the laptop.
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