<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head> <meta content="text/html; charset=ISO-8859-1" http-equiv="content-type"> <title>Pseudo FSK</title><meta content="Dave Freese" name="author"></head> <body style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 204);" alink="#000099" link="#000099" vlink="#990099"> <h2><font size="5"><b>Using the FLdigi Pseudo FSK (Rt. Channel) function to key a transmitter</b></font></h2> <p style="text-align: center;"> <img style="width: 520px; height: 318px;" alt="" src="images/config-rtty.png"></p>Select<small><small><font size="5"><small><small> the PseudoFSK check boxes.<br> </small></small></font></small></small><small><small> </small></small><br> <small><small> </small></small> <br> <small><small> <font size="5"><small><small></small></small></font></small></small><small><small><font size="5"><small><small>FLdigi is now ready to generate a 1000 hertz tone burst signal on the</small></small></font></small></small><small><small><font size="5"><small><small> right channel of the stereo audio out of your sound card. </small></small></font></small></small><small><small><font size="5"><small><small>This tone burst is on when the RTTY bit is on and off when the RTTY bit is off. The left channel will be the normal AFSK signal.</small></small></font></small></small><small><small> </small></small> <br> <small><small> </small></small> <br> <small><small> <font size="5"><small><small>The following circuit may be used to take the FLdigi PSEUDO-FSK signal from the</small></small></font></small></small><small><small><font size="5"><small><small> right channel of your SOUND CARD to key your transmitter's FSK input line. You may find it necessary to invert the sense of the keying signal.</small></small></font></small></small> <p style="text-align: center;"> <img style="width: 714px; height: 368px;" alt="" src="images/CWkeyingCircuit.jpg"> </p> <small><small><font size="5"><small><small>NOTE:</small></small></font> </small></small><br><small><small> </small></small><br><small><small> <font size="5"><small><small>L1 Radio Shack has two items that may be used for this isolation transformer.</small></small></font> </small></small><br><small><small> </small></small><br><small><small> <big><big>Catalog # 270-054, and</big></big></small></small><br><small><small><big><big> Catalog # 273-1374</big></big></small></small><br><small><small><big><big> </big></big></small></small><br><small><small><font size="5"><small><small> Attach an audio cable from the Rt. Channel out of the your computer's SOUND CARD to the input of this FSK</small></small></font><font size="5"><small><small> INTERFACE CIRCUIT (input of L1).</small></small></font></small></small> <br><small><small> <font size="5"><small><small>Attach another cable from the output of this circuit to your Rig's Keying FSK Jack.</small></small></font> </small></small> <p><small><small> <font size="5"><small><small>Every PSEUDO-FSK tone that is generated by FLdigi is rectified by this FULL WAVE VOLTAGE DOUBLER circuit. The resultant voltage turns the Q1 transistor on and "grounds" the collector.</small></small></font></small></small></p><small><small> </small></small> </body></html>
