pages tagged kenwoodFeeding the Cloudhttps://feeding.cloud.geek.nz/tags/kenwood/Feeding the Cloudikiwiki2021-06-23T03:58:44ZReceiving slow-scan television images from the International Space Stationhttps://feeding.cloud.geek.nz/posts/receiving-sstv-images-from-iss/
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2021-06-23T03:58:44Z2020-01-02T00:00:00Z
<p>Thanks to a fellow <a href="https://vectorradio.ca">VECTOR</a> volunteer <a href="https://www.qrz.com/db/VE7NCD">Nick
Doyle</a>, I found out that the <a href="https://en.wikipedia.org/wiki/International_Space_Station">International
Space Station</a>
would be broadcasting <a href="https://en.wikipedia.org/wiki/Slow-scan_television">slow-scan
television</a> images at
the end of the year. I decided to try and pick those up with my handheld
radio.</p>
<h1 id="Planning">Planning</h1>
<p>From the <a href="https://ariss.pzk.org.pl/sstv/">official announcement</a>, I got the
frequency (145.800 MHz) and the broadcast times.</p>
<p>Next I had to figure out when the ISS would be passing over my location.
Most of the ISS tracking websites and applications are aimed at people
wanting to <em>see</em> the reflection of the sun on the station and so they only
list the passes during nighttime before the earth casts a shadow that would
prevent any visual contacts.</p>
<p>Thankfully, Nick found a site which has a option to show all of the passes,
visible or not and so I was able to get a <a href="https://heavens-above.com/PassSummary.aspx?satid=25544&lat=49.2827&lng=-123.1207&loc=Vancouver&alt=0&tz=PST">list of upcoming passes over
Vancouver</a>.</p>
<h1 id="Hardware">Hardware</h1>
<p>From a hardware point-of-view, I didn't have to get any special equipment. I
used my <a href="https://www.kenwood.com/usa/com/amateur/th-d72a/">Kenwood D72</a> and
an external Comet SBB5 mobile antenna.</p>
<p>The only other pieces of equipment I used was a 2.5mm mono adapter which I
used to connect a 3.5mm male-male audio cable in the speaker port of the
radio and the microphone input of my computer.</p>
<h1 id="Software">Software</h1>
<p>The software I used for the recording was
<a href="https://www.audacityteam.org/">Audacity</a> set to a <strong>sampling rate of 48
kHz</strong>.</p>
<p>Then I installed
<a href="http://users.telenet.be/on4qz/qsstv/manual/index.html">qsstv</a> and
configured it to <a href="http://users.telenet.be/on4qz/qsstv/faq.html#Audiofile">read input from a file instead of the sound
card</a>.</p>
<h1 id="Results">Results</h1>
<p>Here is the <a href="https://feeding.cloud.geek.nz/posts/receiving-sstv-images-from-iss/iss_sstv1.ogg">audio I
recorded</a> from the
first pass (65 degrees at the highest point) as well as the rendered image:</p>
<p><img alt="" src="https://feeding.cloud.geek.nz/posts/receiving-sstv-images-from-iss/iss_sstv1.png" /></p>
<p>The second pass (60 degrees) was not as successful since I didn't hold the
squelch open and you can tell from the <a href="https://feeding.cloud.geek.nz/posts/receiving-sstv-images-from-iss/iss_sstv2.ogg">audio
recording</a> that the
signal got drowned in noise a couple of times. This is the rendering of that
second pass:</p>
<p><img alt="" src="https://feeding.cloud.geek.nz/posts/receiving-sstv-images-from-iss/iss_sstv2.png" /></p>
<h1 id="Tips">Tips</h1>
<p>The signal came through the squelch for only about a minute at the highest
point, so I found it best to open the squelch fully (<code>F</code>+<code>Moni</code>) as soon as
the bird is visible.</p>
<p>Another thing I did on a third pass (16 degrees at the highest point -- not
particularly visible) was to plug the speaker out of my radio into a Y
splitter so that I could connect it to my computer and an external speaker I
could take outside with me. Since I was able to listen to the audio, I held
the antenna and tried to <strong>point it</strong> at the <a href="https://heavens-above.com/orbit.aspx?satid=25544&lat=49.2827&lng=-123.1207&loc=Vancouver&alt=0&tz=PST">satellite's general
direction</a>
as well as <strong>varying the orientation</strong> of the antenna to increase the signal
strength.</p>
Using a Kenwood TH-D72A with Pat on Linux and ax25https://feeding.cloud.geek.nz/posts/using-kenwood-th-d72a-with-pat-linux-ax25/
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2021-06-11T20:43:57Z2018-04-20T05:45:00Z
<p>Here is how I managed to get my <a href="http://www.kenwood.com/usa/com/amateur/th-d72a/">Kenwood
TH-D72A</a> radio working with
<a href="http://getpat.io">Pat</a> on Linux using the built-in
<a href="https://en.wikipedia.org/wiki/Terminal_node_controller">TNC</a> and the
<a href="http://linuxdocs.org/HOWTOs/AX25-HOWTO.html">AX.25</a> mode</p>
<h1 id="Installing_Pat">Installing Pat</h1>
<p>First of all, download and install the <a href="https://github.com/la5nta/pat/releases">latest Pat
package</a> from the GitHub project
page.</p>
<pre><code>dpkg -i pat_x.y.z_amd64.deb
</code></pre>
<p>Then, follow the <a href="https://github.com/la5nta/pat/wiki/AX25-Linux">installation
instructions</a> for the AX.25
mode and install the necessary packages:</p>
<pre><code>apt install ax25-tools ax25-apps
</code></pre>
<p>along with the systemd script that comes with Pat:</p>
<pre><code>/usr/share/pat/ax25/install-systemd-ax25-unit.bash
</code></pre>
<h1 id="Configuration">Configuration</h1>
<p>Once the packages are installed, it's time to configure everything
correctly:</p>
<ol>
<li>Plug the radio onto the computer using a mini-USB cable.</li>
<li>Power cycle the radio.</li>
<li>Enable TNC in <code>packet12</code> mode (<strong>band A</strong>*).</li>
<li>Tune band A to <a href="https://vectorradio.ca/ops/frequency-list/">VECTOR
channel</a> 420
(or <a href="https://www.repeaterbook.com/repeaters/details.php?state_id=CA02&ID=3586">421</a>
if you can't reach <code>VA7EOC</code> on simplex).</li>
<li><p>Put the following in <code>/etc/ax25/axports</code> (replacing <code>CALLSIGN</code> with your
own callsign):</p>
<pre><code> wl2k CALLSIGN 9600 128 4 Winlink
</code></pre></li>
<li><p>Set <code>HBAUD</code> to <strong><code>1200</code></strong> in <code>/etc/default/ax25</code> and make sure that the
<code>DEV</code> variable is set to the correct <code>/dev/TTYUSBx</code> device (check the
output of <code>dmesg</code> after turning on the radio).</p></li>
<li><p>Download and compile the <a href="https://github.com/fmarier/tmd710_tncsetup/blob/master/tmd710_tncsetup.c"><code>tmd710_tncsetup</code>
script</a>
mentioned in a comment in <code>/etc/default/ax25</code>:</p>
<pre><code> gcc -o tmd710_tncsetup tmd710_tncsetup.c
sudo cp tmd710_tncsetup /usr/local/bin
</code></pre>
<p>Note: on a <a href="https://www.debian.org/releases/bullseye/">Debian bullseye</a> or later system, all you need to do is install the <a href="https://packages.debian.org/bullseye/tmd710-tncsetup"><code>tmd710-tncsetup</code> package</a>:</p>
<pre><code> apt install tmd710-tncsetup
</code></pre></li>
<li><p>Add the <code>tmd710_tncsetup</code> script in <code>/etc/default/ax25</code> and use these command
line parameters (<code>-B 0</code> specifies band A, use <code>-B 1</code> for band B):</p>
<pre><code> /usr/local/bin/tmd710_tncsetup -B 0 -S $DEV -b $HBAUD -s
</code></pre>
<p>Note: the path is <code>/usr/bin/tmd710_tncsetup</code> if using the official Debian package.</p></li>
<li><p>Start ax25 driver:</p>
<pre><code> systemctl start ax25.service
</code></pre></li>
</ol>
<p>As the AX25 unit starts up and initializes the TNC using <code>tmd710_tncsetup</code>,
you should see <code>STA</code> and <code>CON</code> indicators flash briefly in the top-right
corner of the screen.</p>
<h1 id="Connecting_to_a_winlink_gateway">Connecting to a winlink gateway</h1>
<p>To monitor what is being received and transmitted:</p>
<pre><code>axlisten -cart
</code></pre>
<p>Then create aliases like these in <code>~/.wl2k/config.json</code>:</p>
<pre><code>{
"connect_aliases": {
"ax25-VA7EOC": "ax25://wl2k/VA7EOC-10",
"ax25-VE7LAN": "ax25://wl2k/VE7LAN-10"
},
}
</code></pre>
<p>and use them to connect to your preferred Winlink gateways by starting pat
using the following:</p>
<pre><code>pat http
</code></pre>
<p>and then opening the interface in a webbrowser: <a href="http://localhost:8080/">http://localhost:8080/</a></p>
<h1 id="Troubleshooting">Troubleshooting</h1>
<p>If it doesn't look like ax25 can talk to the radio (i.e. the TX light
doesn't turn ON), then it's possible that the <code>tmd710_tncsetup</code> script isn't
being run at all, in which case the TNC isn't initialized correctly.</p>
<p>On the other hand, if you can see the radio transmitting but are not seeing
any <strong>incoming packets</strong> in <code>axlisten</code> then double check that the speed is
set correctly:</p>
<ul>
<li><code>HBAUD</code> in <code>/etc/default/ax25</code> should be set to <strong>1200</strong></li>
<li>line speed in <code>/etc/ax25/axports</code> should be set to <strong>9600</strong></li>
<li><code>SERIAL_SPEED</code> in <code>tmd710_tncsetup</code> should be set to <strong>9600</strong></li>
<li>radio displays <code>packet12</code> in the top-left corner, not <code>packet96</code></li>
</ul>
<p>If you can establish a connection, but it's very <strong>unreliable</strong>, make sure that
you have enabled software flow control (the <code>-s</code> option in
<code>tmd710_tncsetup</code>).</p>
<p>If you can't connect to <code>VA7EOC-10</code> on UHF, you could also try the VHF BCFM
repeater on Mt Seymour, <a href="http://www.bcfmca.bc.ca/lanvhf.php">VE7LAN</a> (VECTOR
channel 65).</p>