<h2><img src="file:///C:/DOCUME%7E1/CARLOS%7E1.CBN/DEFINI%7E1/Temp/moz-screenshot-5.jpg" alt=""></h2><h2>_________________________________________________________<br></h2><h2>Sound Card Interfacing for RTTY, PSK31, and SSTV</h2>
<p align="justify"><font face="Verdana, Arial" size="2">Who
needs a collection of interface connections to choose from when having
a desire to use the Soundboard in their computer to provide capability
for using RTTY, PSK31, and SSTV modes on the amateur bands? Well from
my experience the answer is many of us, me included. After a large
amount of research I found the following circuits helpful when setting
up my own system. If you have problems setting input and output levels
to your sound card you should consider a resistive pad in the input or
output circuits as shown in following interfaces. Do you need the
pad? Well consider my level discussion (<a href="http://www.w5bbr.com/Levels.html">click here)</a>. Hope these interface circuits and level discussions are of some value to all. Nothing like ideas you know.<br>
</font></p>
<p align="justify"><font face="Verdana, Arial" size="2">One of the best
sources for interfacing both the soundboard and TNC's is contained on
N1RCT's home page. Dick has done a great job both graphically and via
words to describe interfacing. Try this URL as a real source to provide
ease of headaches when it comes to interfacing: <a href="http://www.megalink.net/%7En1rct/rit2/pttfsk.html">Dick Stevens, N1RCT</a> .</font></p>
<p align="center"> <strong><font size="2">JVCOM Interface </font></strong></p>
<p align="center"><img src="http://www.iw5edi.com/wp-content/jvintf.gif" align="middle"></p>
<p align="center"> </p>
<p align="justify"><font face="Verdana, Arial" size="2">The above
circuit is recommended for use in SSTV applications with use of the
sound card with a computer. This is the JVComm style of interface.
This circuit may also be used for RTTY and PSK31 applications. Many
users modify the above circuit to include 1:1 isolation transformers
within the Speaker out and Line-in or microphone in lines. These
isolation transformers are used to preclude ground loops within a
system from introducing hum and interference on the transmitted signals.</font></p>
<p> </p>
<p align="justify"><font face="Verdana, Arial" size="2">The following circuit is used in applications of <a href="http://www.contesting.com/writelog">WinRtty</a>
for receiving RTTY signals using the sound card. This circuit is also
applicable to SSTV and PSK31 modes and works well in all three
applications. This circuit may be implemented into the JVComm
interface shown above as discussed in the JVComm interface text. Note
that the sound board and receiver are transposed in the two circuits.</font></p>
<p align="justify"> </p>
<div style="text-align: center;"><img src="http://www.iw5edi.com/wp-content/winrtty1.gif"></div>
<div style="text-align: center;" align="left"><font size="2">The following circuit is used in applications of </font><a href="http://www.contesting.com/writelog"><font size="2">WinRtty</font></a><font size="2"> for transmitting RTTY signals using the sound card. Notice this circuit does not have a PTT component and relies on </font><a href="http://www.w5bbr.com/VOX.html"><font size="2">VOX</font></a><font size="2">
for transmit control. This circuit is also applicable to SSTV and
PSK31 modes and works well in all three applications. This circuit
may be implemented into the JVComm interface shown above as discussed
in the JVComm interface text. Note that the sound board and
transmitter are transposed in the two circuits.</font></div>
<div style="text-align: center;" align="left"><font size="2"><img src="http://www.iw5edi.com/wp-content/winrtty2.gif"></font></div>
<font size="2">
</font>
<p align="justify"><font size="2"><font face="Verdana, Arial" size="2">So you say "I want FSK capability as well as Push-To-Talk" (PTT). The following circuit is used with <a href="http://www.contesting.com/writelog">WinRtty</a>
to provide capability for FSK Rtty and a PTT circuit for the program.
This circuit may be used in many applications and may be substituted
for the circuit contained in the JVComm interface shown above.</font></font></p>
<p><font size="2"><font face="Verdana, Arial" size="2"><img src="http://www.iw5edi.com/wp-content/winrtty3.gif"></font></font></p>
<p align="justify"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"> </font></font></font></font></p>
<p align="justify"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2">What
goes in the "RS-232 conversion" box depends on your transmitters FSK
input. Odds are, it can be exactly the same as the circuit shown for
the PTT connect: use an opto-isolator with a series resistor to convert
the RS-232 levels to open/close keying. The portion of this circuit
related to PTT may also be used instead of the PTT circuit in the
JVComm interface described above.</font></font></font></font></font></p>
<p><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"> </font></font></font></font></p>
<p><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"> </font></font></font></font></p>
<p><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"> </font></font></font></font></p>
<center><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2">
</font></font></font></font><p><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"> </font></font></font></font></p>
<p><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"> </font></font></font></font></p>
</center><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2">
</font></font></font></font><p align="justify"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2">Another approach to interfacing is contained in the following schematic obtained from <a href="http://www.qsl.net/wm2u/psk31.html">WM2U's</a> home page related to PSK31 and should work for PSK31, RTTY, and SSTV.</font></font></font></font></font></p>
<p align="justify"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2">The
simplest and quickest computer to radio interface is to connect the
Line Output from the Sound Card to the transceiver audio input with a
100:1 voltage<br>
divider to reduce the voltage output, and the Sound Card Line Input to
the audio output of the radio. You can use the VOX to switch from
Receive to Transmit.<br>
To setup this arrangement, adjust the sound card output level using the
computer 'mixer' control until maximum transmit power is reached, and
the ALC is<br>
just starting to read. Then tune to a strong carrier and adjust the
soundcard input gain until the red line goes away as observed on the
spectrum display.<br>
(waterfall indicator) This procedure is covered in great detail in the PSK31 Help files under "setting up the sound card".</font> <img src="http://www.iw5edi.com/wp-content/interface1.gif"></font></font></font></font></p>
<p align="justify"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"> </font></font></font></font></p>
<font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2">
</font></font></font></font></font><div style="text-align: center;" align="left"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><font size="2">The
circuit below shows the method WM2U used which isolates the Sound Card
Line In and Line Out from the Radio using a couple of Radio Shack
transformers, and a 2N2222<br>
transistor to switch the PTT radio line triggered by the RTS line of
the computer Com Port. All audio levels are equalized when running
either the computer, the SSTV program<br>
or PSK31. A switch is used to switch between Computer and the Radio
Modes. To adjust this circuit, tune to a strong carrier and tweek RV1
until the red overload lines<br>
disappear. At this point simply tweek RV2 to give the required output power from the transmitter.<br>
The author of this information is <a href="http://www.qsl.net/wm2u">WM2U.</a> <img src="http://www.iw5edi.com/wp-content/interface.gif"></font></font></font></font></font></font></div>
<div style="text-align: center;" align="left"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><font size="2">To
completely isolate the computer from the radio the PTT line schematic
shown above should be replaced by the following optically coupled
circuit. WM2U has this unit installed and it works great.</font></font></font></font></font></font></div>
<div style="text-align: center;" align="left"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><img src="http://www.iw5edi.com/wp-content/interface2.gif"></font></font></font></font></font></div>
<div style="text-align: center;" align="left"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><font size="2">Another interesting PTT circuit from G3VFP to cover both the RTS and/or DTR source.<br>
You can use a 2N2222 in place of the BC337 transistor in this circuit.</font></font></font></font></font></font></div>
<font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><font size="2">
</font></font></font></font></font></font><div style="text-align: center;" align="left"><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><font size="2"><font size="2"><img src="http://www.iw5edi.com/wp-content/pttlog.jpg"></font></font></font></font></font></font></font></div>
<font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><font size="2"><font size="2">
</font></font></font></font></font></font></font><font size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font face="Verdana, Arial" size="2"><font size="2"><font size="2"><font size="2"><font size="2">Original article was available here<font color="#000080"><strong> </strong></font><a href="http://www.w5bbr.com/index.html"><strong>http://www.w5bbr.com/index.html</strong></a> or <span style="font-weight: bold;"><a href="http://www.w5bbr.com/soundbd.html">http://www.w5bbr.com/soundbd.html</a><br>
<br></span><br></font></font></font></font></font></font></font></font>________________________________________________________________________________________<br><div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br> <br> Jose Alves escreveu:<br> ><br> > Estimados Colegas,<br> ><br> ><br> ><br> > Venho por este meio solicitar uma ajuda, procuro um interface simples<br> > para ligar o meu Icom 706 MKIIG á placa de som, para poder fazer modos<br>
> digitais (RTTY, PSK, Etc)<br> ><br> ><br> ><br> > Sem outro assunto<br> ><br> ><br> ><br> > José Alves<br> ><br> ><br> ><br> > <a href="mailto:c1fhw@clix.pt">c1fhw@clix.pt</a><br>
><br> > ------------------------------------------------------------------------<br> ><br> <br><br></blockquote></div><br><br clear="all"><br>