Tag: dipole

Show Notes #091

Posted on by Russ Woodman

Introduction:

  • It's Second Spring in Texas, and Autumn is beginning in Arkansas, so sit back and enjoy another exciting episode of LHS.

Announcements:

  • Paid subscribers to LHS may have noticed the web site certificate had expired. That problem is fixed.
  • Welcome new subscribers Michael S., Michael C., and Bill A. Thank you!
  • Sign-up for the LHS mailing list.
  • Our LHS Ambassador to Ohio LinuxFest will be Scott, N8VSI. Thanks, Scott, and we look forward to hearing all about it.
  • Please donate to the podcast and click on the affiliate links on the website.

Topics:

  • HF Antennas, Horizontal vs. Vertical
    • Tonight, our hosts discuss the pros and cons of horizontally and vertically polarized HF antennas.
    • One thought is that once the RF radiation hits the various layers in the ionosphere, the polarization doesn't really matter much as it gets reflected to and fro.
    • Richard offers the practical reason for preferring horizontal antennas for HF: it's easier to build and erect the long antennas necessary for these frequencies. However, for chasing DX, those long-distance contacts, many hams prefer vertical antennas as they tend to have lower angles of radiation.
    • Also mentioned: GAP antennas and the G5RV antenna.
    • Wire horizontal dipoles are inexpensive and easy to construct. Verticals are a good choice when space is limited and can have a lower take-off angle, providing a good ground radial system is installed beneath them.
    • Horizontal antennas can be more directional. A dipole wire running north and south will have a better propagation east and west. A vertical is omnidirectional, radiating equally in all directions. To complicate matters, a horizontal antenna lower to the ground will radiate at higher angles than the same antenna that is higher. This can be useful for communicating with stations that are close to you.
  • A new section of the podcast: Russ' Rant!
    • Russ has a Yaesu FT-7900R, a dual-band UHV/VHF mobile radio. It has a removable front panel, allowing the main part of the radio to be hidden and the display can be easily mounted on the dash. However, the speaker is on the body of the radio, so you can't hear it if it's hidden under the seat or in the trunk! Russ thinks the head unit should also contain a speaker, perhaps a very small one like in an mp3 player. Or put the speaker in the microphone.
  • Returning to antennas, Richard recommends that KD8SZG (in the chat room), should try building his own wire antennas for HF. Any of the antenna books written by Doug DeMaw, W1FB, are good resources. His Antenna Notebook is one. (I also like the various ARRL antenna books, like the Simple and Fun Antennas for Hams. -Ed.)

Contact Info:

  • Contact Richard at kb5jbv@gmail.com, Russ at k5tux@lhspodcast.info, or both at the same time at info@lhspodcast.info.
  • Listen to the live stream every other Tuesday at 8:00pm Central time. Check the LHS web site for dates.
  • Leave us a voice mail at 1-909-LHS-SHOW (1-909-547-7469), or record an introduction to the podcast.
  • Sign up for the LHS mailing list.
  • Sign up for the MAGNetcon mailing list.
  • LHS merchandise is available at the Merch link on Web site. Check out the Badgerwear or buy one of the other LHS-branded items at PrintFection.com/lhs or Cafe Press. Thanks!
  • Thanks to Dave from Gamma Leonis for the theme music.

Music:

  • "A Little Time" by Not From Georgia, from their album Love & Umbrella, courtesy of Jamendo.
  • "Metal Heart" by Zamza, from their album Songs for Jukebox, courtesy of Jamendo.

Show Notes #084

Posted on by Russ Woodman

Introduction:

  • No music this time; just one hour jam-packed with LHS goodness!

Announcements:

  • Remember to sign up for the following LHS services:
    • The LHS SubReddit
    • The LHS Mailing List
    • The LHS Mobile app. Follow our updates via the mobile applications available for iPod, iPhone, iPad and Android devices.
    • Be an LHS Ambassador! Please join our Ambassador program. The event calendar has expanded quite a bit and we need your help. These events are now world-wide, so we could use some help outside the US as well as all over the country from California to Maine.
  • YFKtest: Yes, there really does seem to be a problem. It's been confirmed by John, EI7IG, that the program does not log contacts for the ARRL Field Day contest. Other contests work fine. Russ plans on emailing the developer, DJ1YFK, with these observations.
  • From the "Yes, It's an Antenna" File: Multi-band HF dipole made from horse fencing.
  • Pulling a Lunduke: Holding Source Code Hostage. Our hosts discuss this blog post by Tom Nardi about Bryan Lunduke's recent move to open source his software. Bryan is one of the hosts of The Linux Action Show.

Topics:

  • Software Defined Radio (SDR)
    • A common topic Russ encountered at Dayton was about the available Linux options for software defined radios.
    • GNU Radio Project
      • Version 3.6.0 released in early May, 2012.
      • Version 3.2.2 is in the Debian Sid repository.
      • The latest version can be retrieved with git. (Install git with the command "apt-get install git".) To download the software, issue the command "git clone git://gnuradio.org/gnuradio".
      • Build instructions are available for most of the major Linux distributions.
    • SDR Hardware
      • Ettus USRP series works with the GNU Radio Project software. There are various models ranging in price from $700 to $2000, depending on the frequency range and options. Various modules allow receive and/or transmit on bands from 30kHz to 5.9GHz. Unfortunately, power output appears to be just 50-200mW, depending on the bands provided by the transmitter daughter board chosen.
      • Funcube Dongle costs £128 (~$200) and is a receiver only. The Funcube Dongle is a "radio receiver designed to allow anyone to try their hand at reception of satellites like FUNcube". It covers 51.5MHz - 1.7GHz, less the region from 1.1GHz to 1.2GHz.
      • Perseus SDR costs $1000 and is also receive-only. It receives 10kHz to 40MHz.
      • SoftRock SDR is a kit available in various models from $20 to $90. Most are receive-only, but the Ensemble is a 1W HF transceiver. Some models are unavailable at the moment. The SoftRock RXTX Ensemble Transceiver Kit will allow you to build a 1W transceiver for one of the following bands or band groups: 160m, 80m/40m, 30m/20m/17m, or 15m/12m/10m.
      • RTL-SDR Devices range in price from $20 to $200 and are receive-only. More on the RTL-SDR project in an upcoming episode.

Feedback:

  • Stewart, VA3PID, wrote to say that Russ was the first person, possibly ever, to correctly place his Scottish accent at Hamvention. He also remarked (in reference to a discussion in episode 71) that Chirp has come a long way; it can now program his Yaesu FT-857D!
  • Jonas recently re-discovered LHS and expressed his appreciation for the show. Thanks, Jonas!
  • Stefano, IZ3NVR/KD2BGM, asks for more help getting so2sdr built on his Linux machine. Russ suggests installing the compiler with "apt-get install g++ build-essential", installing Qt and several other packages as described in Episode 83, then try building the so2sdr program again.
  • Lastly, David Dominicki left a mostly unintelligible comment in response to Episode 78. Um, thanks... we think.

Contact Info:

  • Contact Richard at kb5jbv@gmail.com, Russ at k5tux@lhspodcast.info, or both at the same time at info@lhspodcast.info.
  • Listen to the live stream every other Tuesday at 8:00pm Central time. Check the LHS web site for dates.
  • Leave us a voice mail at 1-909-LHS-SHOW (1-909-547-7469), or record an introduction to the podcast.
  • Sign up for the LHS mailing list.
  • Sign up for the MAGNetcon mailing list.
  • LHS merchandise is available at the Merch link on Web site. Check out the Badgerwear or buy one of the other LHS-branded items at PrintFection.com/lhs or Cafe Press. Thanks!
  • Thanks to Dave from Gamma Leonis for the theme music.

Music:

  • None.

LHS Show Notes #057

Posted on by Russ Woodman

Introduction:

Announcements:

Topics:

  • Richard and Russ talk about the origins of the LHS podcast name. See Linux on the Desktop podcast.
  • Richard talks about how to build a Delta loop antenna, and using a piece of 75 ohm coax to act as a matching transformer between the antenna and the 50 ohm feed line. He also describes velocity factor for coaxial cable. Here's an illustration of a 20m Delta loop similar to what Richard describes.
  • Just for fun: Fab's Crap Alert
  • linSmith, in the Debian repositories, is a program for plotting Smith Charts, and more.
  • Richard then talks about Henry Allen W5TYD, formerly K5BUG, of Texas BugCatcher antenna fame, and the inductors he wound around Plexiglas forms. (Henry ceased production of his antennas in 2009 and has retired. -Ed.)
  • Russ uses an Alpha Delta DX-CC multiband dipole, in preference to a G5RV dipole.
  • Other antennas mentioned:
  • Impedance of transmission lines: 50 ohms for communications coaxial cable, 75 ohms for cable TV coaxial cable, 300 ohms for the old TV twinlead, 450 ohms for window line, and typically 600 ohms for ladder line.
  • Richard explains Standing Wave Ratio (SWR).
  • Richard relates an Field Day story from several years ago... Commodore-64 running packet radio on the tailgate of a truck in 100-degree heat, and burning up the C-64.

Feedback:

  • Audio feedback from Frasier K. thanking our hosts for the podcast. He's currently studying for his ham license via HamTestOnline, and learned about Linux from the podcast. He's now running Ubuntu 10.10 on his laptop and rockbox on his iPod. He'd like some sort of automatic calendar reminder service to alert him when a new episode will be recorded. Thanks, Frasier, and we'll look into that.
  • Mitch, KC2MBN, says that he enjoys the podcast. He's now an Extra class licensee, but is new to Linux. He recently tried dual-booting Windows 7 with Pinguy OS and reports some troubles, and asks for some recommendations for a distro. Thanks, Mitch. If you have a spare machine, it would be better to run Linux on that rather than going to the trouble and risk of dual-booting. You might try actual Ubuntu, Debian or Linux Mint. Crunchbang Linux is also easy to install, as is PCLinuxOS.

Contact Info:

  • Contact Richard at kb5jbv@gmail.com, Russ at k5tux@lhspodcast.info, or both at the same time at info@lhspodcast.info.
  • Listen to the live stream every other Tuesday at 8:00pm Central time. Check the LHS web site for dates.
  • Leave us a voice mail at 417-200-4811, or record an introduction to the podcast.
  • Sign up for the LHS mailing list.
  • Sign up for the MAGNetcon mailing list.
  • LHS merchandise is available at the SHOP! link on Web site. Check out the Badgerwear or buy one of the other LHS-branded items at PrintFection.com/lhs or Cafe Press. Thanks!
  • Thanks to Dave from Gamma Leonis for the theme music.

Music:

  • "Bad Boy (For You)" by Rebolt from the album "Made in Spite EP" courtesy of Jamendo.
  • "Daylight" by Singleton from the album "The High Seas" courtesy of Jamendo.