radioAe6rt

The latest addition to my radio library is Experimental Methods in RF Design. From the first chapter, we understand what good hands we are in with these authors.

[tags]ham radio, rf[/tags]

For the last year I’ve been into operating continuous wave using Morse Code. While it sounds odd, I believe there is something pleasurable from a brain chemistry perspective when processing Morse Code. Something like a focussing opiate.

Code is not just fun – this is not about fun, but rather pleasure. Code is not quite like music, because code is work, and the way I listen to music is usually not. Code is definitely not like listening to and processing human speech, because code is much simpler than human language.

But taking in Morse Code actively feels good. It’s pure, simple, and feels like orange juice for the brain. It would be interesting to see a brain scan during listening to speech, listening to music, and listening to code to see the similarities and differences in which parts of the brain are stimulated.

[tags]morse code, cw, ham radio[/tags]

SolderSmoke offers podcasts of discussions of QRP construction projects. Very, very cool.

[tags]ham radio, qrp, radio kits[/tags]

I want to plug these two books, because I value them at the same level as Jackson’s Electrodynamics or Corson and Lorrain’s Electromagnetic Fields and Waves

• Paul Nahin’s Science of Radio
• Dave Rutledge’s The Electronics of Radio

When I think about antennas, I often end up thinking about Maxwell’s Equations and radiating dipoles. I can’t help it, and rightly so, and which is where Jackson’s text comes in. But after Jackson, which is dense and of biblical authority, you want to read something a bit more practical and accessible.

The two books above are great complements in the quest to understand RF phenomena. Nahin treats the history and basic physics of radio, while Rutledge treats a real working analog radio, the NorCal40a. You can buy the NorCal40a in kit form, assemble it, operate it, and read about every aspect of its theory of operation in Dave’s book. Wow. So cool.

RF science is genuinely hard, because you’re dealing with time varying propagating fields in real world physical systems. Here, real world is shorthand for extremely complicated and begging for first and second order approximations. These two books get us started in those approximations and the radio physics they describe.

[tags]rf, radio frequency, radio, electrodynamics, ham radio[/tags]

I’m looking for sources of interactive line of sight maps, such as this sample which shows what can be seen (sort of) from Contractor’s Point in the San Fernando Valley, CA.

Anybody?

[tags]maps, line of sight maps,rf propagation, ham radio[/tags]

Last fall I built a NorCal40a 40m CW transceiver as a QRP rig and trail radio (ham radio). The rig includes the optional KC-1 Keyer, which allows me to use a paddle key instead of a straight key.

For trail use, where the radio, power supply, tuner, antenna, and key would be stuffed in a backpack and hauled in, I wanted all the components to be as light, small, and rugged as possible. The power supply is a set of 10 AA batteries mounted in inexpensive battery holders of the type readily found at RadioShack. The tuner built from kit is the Emtech ZM2, and the antenna a half wavelength longwire made from a single strand of 21 gauge speaker wire, with a quarter wavelength counterpoise made from the same. To store the antenna, I roll it up on a 12″ spool made from a length of old broomstick.

To store the rig, I found at Target a plastic, shoebox-sized box with lid in which the entire rig fits. The box fits nicely within either a day pack or larger backpack. Total weight is about 5lbs., which is fine for day trips. On longer, hike-in trips, where you’re carrying food plus everything else you need to survive, 5lbs is a bit heavy. Priorities.

Paddle touches are pretty personal, and if you don’t like the touch and action of a paddle, you probably won’t have the fun with it you could be having. I have a very nice Begali Simplex paddle that I use with my home, essentially nonportable, radio. This paddle is not going on the trail with me, at a hefty 3 pounds itself. Besides, this paddle is a work of art and mechanical princess, and should be used in friendly environments, not outside or stuck in the bottom of a pack. While the Begali may be able to take this sort of abuse, I won’t subject mine to it.

So for trail use, I considered using a Paddlette BP, but couldn’t get comfortable with how the key would perform, based solely on an inspection of the product photos. It looked larger than what I wanted. This may be a great trail paddle, but I never got around to trying it. I actually did try a Vibroplex Code Warrior, Jr.. While this was a nice key, it, too was too large and heavy for my backpacking considerations.

Eventually I settled on the Palm Radio Mini Paddle and couldn’t be more pleased with the product. It’s very small and light, and has a terrific action. I operate it by grasping the paddle body with my left hand as I would grip a bicycle handlebar, rest that left hand on my right knee, and operate the paddle with my right hand, which is also resting on my right knee. This configuration provides enough stability to comfortably and accurately generate clean code.

The Mini-Paddle action is clean, crisp, and sure and the construction compact and rugged. When not in use, the paddles can be stowed inside the paddle housing to protect them and reduce the paddle’s stowage space requirements – both very important features. Space requirements for the paddle are about the same as a pack of chewing gum or pocket knife.

This is a great little portable paddle, easy to handle with crisp, firm keying action.

[tags]ham radio, cw, telegraphy, morse code[/tags]

Some time ago I ran across Jim Kortge’s pictures of the 2n2/20 20m rig he built using ground plane construction techniques.

Absolutely gorgeous work.

Wow.

[tags]ham radio, ground plane construction, radio kits, radio[/tags]

Does anyone know if there are unlicensed HF bands in the US, as there are unlicensed UHF ISM bands where WiFi has bloomed?

Ham operators have been operating on low power (sub 5W) for years. But how cool would it be to open a slice of the HF band to unlicensed low power use, and see what cool services would emerge. Owing to the physics of wave propagation, longer HF radio waves travel further easier than short VHF and UHF waves. HF propagation is also more susceptible to atmospheric conditions, but that’s ok — that’s part of the challenge. We’re talking about 10-80m roughly, which means antenna sizes change relative to the familiar 10cm-ish WiFi antennas. For example, at 10m the antenna needs to be about 15ft long.

To whet the appetite, here is some very cool work done in licensed spectrum in HF digital radio.

Hmm.

The open source creative outlet of my early teen years was the Heathkit radio product line. Buy the kit, assemble the radio yourself, and learn a lot about how the radio works in the process. Smell the solder while you’re at it. This, like everything else with fond memories (new-car smell), is of course now bad for your health. Well, whatever. Smell the solder anyway.

Get a ham Technician license, which is real easy. If you like wireless as a superset of WiFi, you’ll get to send your radio signals across the world rather than just around the house.

And then check out the $130 NorCal40a or the higher end $600 Elecraft. Building these kits gets a guy outside the pure software world into the physical realm, where the winding spacing on toroids matters.

That said, if you prefer a mix of hardware and software, take that $600+ and get yourself an Ettus Research USRP, a platform on which you can do GNU Software Radio. GNU Radio has an active developer community, and will support you while you learn how to make the radio do what you want it to do via signal processing code you write.

Wireless is more than just WiFi. Check ‘em out.

[tags]ham radio, software radio, radio kits, gnuradio[/tags]

From now until 2359 UTC tomorrow, we find ourselves in a worldwide CW (Morse code) contest going on on the ham bands. The contest is one of several like it during the year, and this one is sponsored by CQ Magazine. The spectrum analyzer on my rig on 20m shows some serious participation. The bands are on fiyahh!

It warms my heart to know that hams around the globe are pounding brass for the next day or so over this first of the holiday weekends. I look over at the rig, or turn the volume up, and hear the community coming together to compete, keep their code skills sharp, and otherwise just have a good time.

Long live Morse code in the amateur ranks and the music it makes.