LHS Show Notes #060


Topic 1: JT65

  • Richard enjoys the digital modes. Recently, he came across a signal he could not immediately identify, and found it was JT65.
  • JT65 is one of the suite of programs in the WSJT package written by Joe, K1JT, and was originally developed for weak signal Earth-Moon-Earth (EME) contacts.
  • It’s easier to install than WSPR (Weak Signal Propagation Reporter); simply download, extract, and go.
  • Because the software is designed to achieve a weak signal contact, information is sent repeatedly. If everything is working well, a simple contact will take about 7 minutes.
  • Like WSPR, stations transmit on a two-minute interval, so the computer clock must be accurate.
  • One station will “transmit on the ones” meaning he is transmitting on the odd number minutes. Each transmission is usually about 50 seconds. Then, the other station sends on the even minutes.
  • Typical contacts are callsign, signal report, and location.
  • Signals sound a bit like weather fax, usually a bit above the PSK area on 20m.
  • Richard was able to make 10 contacts in 15 minutes with 5 watts into his G5RV at 30 feet, on the 10m band, no less. He then made 5 contacts in 30 minutes on 15m, one of which was to South America.
  • WSJT and WSPR are both developed by Joe, K1JT, a physicist and amateur radio operator.
  • WSJT and WSPR can be found at http://www.physics.princeton.edu/pulsar/K1JT/index.html.
  • One of the best websites Richard found for learning to use JT65 on HF is “The Complete Bozo’s Guide to HF JT65A by Andy, K3UK”. It hasn’t been updated in a while, but is still a good resource.
  • The manual included with the program is very good, too.
  • Richard recommends using the second set of messages provided in the program, rather than the default set, as the default does not include a signal report.
  • Richard has prepared an “Intro to JT65″ video, available at the RF Podcast website.

Topic 2: Codec2

  • Bruce, VE9QRP, back in January, suggested we talk about Codec2.
  • From the Codec2 website:
    “Codec2 is an Open Source and patent-free audio codec, currently in alpha testing. It provides good voice rendition at 2550 bits per second, and we expect that its bandwidth will be reduced with continuing development. Its voice quality and latency are an improvement over Speex, when Speex is run at a similarly low bandwidth rate. The original motivation for its development was to provide a completely open codec to replace AMBE+, MELP, and other proprietary codecs for use in Amateur (“Ham”) Radio communications. However, the codec is potentially useful for commercial two-way radio, telephony, and other applications.”
  • Russ plays some audio samples, and our hosts discuss how this might be used in ham radio applications.
  • The resulting file is in a .wav container and thus can be played by any program that plays .wav files. While the result is adequate for voice, it’s not suitable for music.
  • More links:


  • We received donations from Dan W., Matt M., Andrew H., and Paul G. Thank you!
  • LHS will be at the Dayton Hamvention, in the North Hall, booth 131. We hope to see you there!
  • Jim, N2ENN, linked to us on his blog site. Thanks, Jim.
  • The Panhandle ARES group linked to LHS on their website. Thanks, guys.
  • regexorcist of The Daemon and Penguin Oggcast linked to LHS. Thank you.
  • Gary, KE2YK, has syndicated the LHS RSS feed on his eHamStore.net site. Thanks, Gary.
  • Burt, K1OIK, thought the clip art of the foo dog (episode 55) looked like Russ.
  • B.B., sent a long email, which we’ll discuss in an upcoming episode.
  • Danny asked about the podcast that Gene has about Apple. That’s the Tech Night Owl Live program with Gene Steinberg.
  • Dave, KI6ZHD, just found the LHS podcast website. Dave has written some documentation for various Linux topics and is a recent ham. His distro of choice is CentOS. He has been documenting his adventures at his blog and thought our listeners might be interested. He asked if we talked about TrustedQSL on Linux, and we did in episodes 43 and 46.
  • Leif, KC8RWR, commented about dual-booting a computer with Windows if Linux has already been installed. He suggests using gparted to shrink the Linux partition, creating a Windows partition in the free space, and then installing Windows. Of course, it’s best to just use a spare computer or another hard drive. (We talked about all this in episode 56.)
  • Richard points out that version 1.0 of CQRLog has been released.
  • Jim, N2ENN, just installed straight Debianand offers a few hints:
    • Extra repositories: In the system/administration tab, there’s a package called software sources. Check them all and click close.
    • Flash vs gnash: don’t worry about gnash. Once the nonfree repositories are selected, open the Synaptic package manager and install flashplugin-nonfree, or from a terminal, type “apt-get install flashplugin-nonfree”.
    • Regarding codecs: all the codecs are already installed, or should be. If not, again in Synaptic, tick good, bad and ugly plugin modules, along with the base plugin.
  • Russ received this from a radio club: Steve, N1NXU, wrote that he had a Tripp-Lite power supply that needed repair and he asked them for a schematic. They declined to provide one, so he recommends Astron power supplies, as schematics are included. These are available a most of the ham radio stores.
  • John, KF6EFG, attended Indiana LinuxFest and asked Russ for a copy of his presentation from that event. Look for that information on the LHS website in the near future.


  • Some listeners have requested a calendar of upcoming LHS events. So, if you have a calendar program that uses ICS calendar feeds, go to the LHS site and on the right side, look for the ‘Follow Us’ heading. Click at the third icon that looks like a calendar. Or, to see the information in your browser, click this https://zmx.bcef.info/service/user/[email protected]/LHS-Podcast.html.
  • Again, LHS will be at the Dayton Hamvention on May 20-22. We’ll be giving away a computer, so drop by the booth and say hello. Please donate at the website to help defray the costs. Thanks.

Contact Info:


  • To be added.
Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].

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