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[homepage.git] / blog / index.rss

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@@ -6,6 +6,73 @@
                 <link>https://people.skolelinux.org/pere/blog/</link>
                 <atom:link href="https://people.skolelinux.org/pere/blog/index.rss" rel="self" type="application/rss+xml" />
        
+       <item>
+               <title>rtlsdr-scanner, software defined radio frequency scanner for Linux  - nice free software</title>
+               <link>https://people.skolelinux.org/pere/blog/rtlsdr_scanner__software_defined_radio_frequency_scanner_for_Linux____nice_free_software.html</link>
+               <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/rtlsdr_scanner__software_defined_radio_frequency_scanner_for_Linux____nice_free_software.html</guid>
+                <pubDate>Tue, 7 Mar 2023 23:10:00 +0100</pubDate>
+               <description>&lt;p&gt;Today I finally found time to track down a useful radio frequency
+scanner for my software defined radio.  Just for fun I tried to locate
+the radios used in the areas, and a good start would be to scan all
+the frequencies to see what is in use.  I&#39;ve tried to find a useful
+program earlier, but ran out of time before I managed to find a useful
+tool.  This time I was more successful, and after a few false leads I
+found a description of
+&lt;a href=&quot;https://www.kali.org/tools/rtlsdr-scanner/&quot;&gt;rtlsdr-scanner
+over at the Kali site&lt;/a&gt;, and was able to track down
+&lt;a href=&quot;https://gitlab.com/kalilinux/packages/rtlsdr-scanner.git&quot;&gt;the
+Kali package git repository&lt;/a&gt; to build a deb package for the
+scanner.  Sadly the package is missing from the Debian project itself,
+at least in Debian Bullseye.  Two runtime dependencies,
+&lt;a href=&quot;https://gitlab.com/kalilinux/packages/python-visvis.git&quot;&gt;python-visvis&lt;/a&gt;
+and
+&lt;a href=&quot;https://gitlab.com/kalilinux/packages/python-rtlsdr.git&quot;&gt;python-rtlsdr&lt;/a&gt;
+had to be built and installed separately.  Luckily &#39;&lt;tt&gt;gbp
+buildpackage&lt;/tt&gt;&#39; handled them just fine and no further packages had
+to be manually built.  The end result worked out of the box after
+installation.&lt;/p&gt;
+
+&lt;p&gt;My initial scans for FM channels worked just fine, so I knew the
+scanner was functioning.  But when I tried to scan every frequency
+from 100 to 1000 MHz, the program stopped unexpectedly near the
+completion.  After some debugging I discovered USB software radio I
+used rejected frequencies above 948 MHz, triggering a unreported
+exception breaking the scan.  Changing the scan to end at 957 worked
+better.  I similarly found the lower limit to be around 15, and ended
+up with the following full scan:&lt;/p&gt;
+
+&lt;p&gt;&lt;a href=&quot;https://people.skolelinux.org/pere/blog/images/2023-04-07-radio-freq-scanning.png&quot;&gt;&lt;img src=&quot;https://people.skolelinux.org/pere/blog/images/2023-04-07-radio-freq-scanning.png&quot; width=&quot;100%&quot;&gt;&lt;/a&gt;&lt;/p&gt;
+
+&lt;p&gt;Saving the scan did not work, but exporting it as a CSV file worked
+just fine.  I ended up with around 477k CVS lines with dB level for
+the given frequency.&lt;/p&gt;
+
+&lt;p&gt;The save failure seem to be a missing UTF-8 encoding issue in the
+python code.  Will see if I can find time to send a patch
+&lt;a href=&quot;https://github.com/CdeMills/RTLSDR-Scanner/&quot;&gt;upstream&lt;/a&gt;
+later to fix this exception:&lt;/p&gt;
+
+&lt;pre&gt;
+Traceback (most recent call last):
+  File &quot;/usr/lib/python3/dist-packages/rtlsdr_scanner/main_window.py&quot;, line 485, in __on_save
+    save_plot(fullName, self.scanInfo, self.spectrum, self.locations)
+  File &quot;/usr/lib/python3/dist-packages/rtlsdr_scanner/file.py&quot;, line 408, in save_plot
+    handle.write(json.dumps(data, indent=4))
+TypeError: a bytes-like object is required, not &#39;str&#39;
+Traceback (most recent call last):
+  File &quot;/usr/lib/python3/dist-packages/rtlsdr_scanner/main_window.py&quot;, line 485, in __on_save
+    save_plot(fullName, self.scanInfo, self.spectrum, self.locations)
+  File &quot;/usr/lib/python3/dist-packages/rtlsdr_scanner/file.py&quot;, line 408, in save_plot
+    handle.write(json.dumps(data, indent=4))
+TypeError: a bytes-like object is required, not &#39;str&#39;
+&lt;/pre&gt;
+ 
+&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
+</description>
+       </item>
+       
        <item>
                <title>OpenSnitch available in Debian Sid and Bookworm</title>
                <link>https://people.skolelinux.org/pere/blog/OpenSnitch_available_in_Debian_Sid_and_Bookworm.html</link>
@@ -638,34 +705,6 @@ worked out.&lt;/p&gt;
 would like to give more visibility.  I&#39;ll stop here to avoid delaying
 this post.&lt;/p&gt;
 
-&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
-</description>
-       </item>
-       
-       <item>
-               <title>LinuxCNC translators life just got a bit easier</title>
-               <link>https://people.skolelinux.org/pere/blog/LinuxCNC_translators_life_just_got_a_bit_easier.html</link>
-               <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/LinuxCNC_translators_life_just_got_a_bit_easier.html</guid>
-                <pubDate>Fri, 3 Jun 2022 21:10:00 +0200</pubDate>
-               <description>&lt;p&gt;Back in oktober last year, when I started looking at the
-&lt;a href=&quot;https://en.wikipedia.org/wiki/LinuxCNC&quot;&gt;LinuxCNC&lt;/a&gt; system, I
-proposed to change the documentation build system make life easier for
-translators.  The original system consisted of independently written
-documentation files for each language, with no automated way to track
-changes done in other translations and no help for the translators to
-know how much was left to translated.  By using
-&lt;a href=&quot;https://po4a.org/&quot;&gt;the po4a system&lt;/a&gt; to generate POT and PO
-files from the English documentation, this can be improved.  A small
-team of LinuxCNC contributors got together and today our labour
-finally payed off.  Since a few hours ago, it is now possible to
-translate &lt;a href=&quot;https://hosted.weblate.org/projects/linuxcnc/&quot;&gt;the
-LinuxCNC documentation on Weblate&lt;/a&gt;, alongside the program itself.&lt;/p&gt;
-
-&lt;p&gt;The effort to migrate the documentation to use po4a has been both
-slow and frustrating.  I am very happy we finally made it.&lt;/p&gt;
-
 &lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
 activities, please send Bitcoin donations to my address
 &lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;