Transmitting Data Long-Distance with Morse Code

[Konstantinos] wrote in to tell us about his CDW project: a digital encoding scheme for ham radio that uses CW (continuous wave) Morse code for digital data transfer. CW operation with Morse code is great for narrow-bandwidth low-speed communication over long distances. To take advantage of this, [Konstantinos] developed a program that takes binary or text files, compresses them, and translates them to a series of letters and numbers that can be represented with Morse code.

The software translates the characters into sequences of Morse code pulses, and plays an audio stream of the result. His software doesn’t support decoding Morse from an audio stream, so [Konstantinos] recommends using one of many existing programs to get the job done. Alternatively those with a good ear and working knowledge of Morse can transcribe the characters by hand.

After receiving a broadcast, the user pastes received characters back in the software. The software re-assembles the binary file from the Morse characters and decompresses the result. [Konstantinos] also added a simple XOR encryption feature, but keep in mind that using encryption on ham radio bands is technically illegal.

Fox Hunting with a Raspberry Pi

No, not a real fox! [KM4EFP] is a ham radio operator with a passion for fox hunting, which is an event where several radio operators attempt to find a broadcasting beacon (a “fox”) using radio direction finding techniques. [KM4EFP] has just built his own portable fox using a Raspberry Pi in a very well-built enclosure.

Since the fox could be outside for a while, the project was housed in a reasonably weatherproof ammunition case. A mount for an antenna was attached to the side, and it is hooked up to a GPIO pin on the Raspberry Pi. The entire device is powered by a 6000 mAh battery pack which allows the fox to broadcast long enough to be found.

The software running on the Raspberry Pi is very similar to the Pi FM transmitter program but it is specially made for ham radio broadcasting instead. Almost no extra hardware is needed to get the Pi broadcasting radio, as these software packages can drive the antenna directly from the GPIO pin. This is a great twist on the standard FM transmitter that ham radio enthusiasts everywhere can use to start finding those wily foxes!

Hacklet 19 – Ham Radio

19

Amateur, or ham radio operators have always been hackers. For much of the early 1900’s, buying a radio was expensive or impossible. Hams would build their own rigs, learning electronics and radio theory along the way. Time moves on, but hams keep hacking. Today we’re highlighting some of the best ham radio projects on Hackaday.io!

rtl

We start with [DainBramage1991] and his very practical RTL-SDR With Upconverter and Case. [DainBramage1991] fell in love with his low-cost RTL software defined radio dongle. He even added a Ham-It-Up upconverter to cover HF bands. The only problem was RF noise. the Realtek USB sticks tend to have little or no filtering, which means they are very susceptible to noise. [DainBramage1991] used the time-honored technique of insulating with copper clad board. Bits of PCB hold the RTL-SDR and upconverter in place. More PCB separates the two boards. Everything goes into a steel enclosure which keeps that unwanted RF at bay.

foxhunt-attenNext up is [Ryan Miller’s aka KG7HZQ]’s  ham radio fox hunt attenuator. Ham radio fox hunt’s don’t involve baying dogs or horses. In this case a fox hunt is a contest to find hidden low power transmitters. If you’ve never tried one, it’s a heck of a lot of fun. One of the challenges with a fox hunt is to find the direction to the transmitter when you’re very close. Even with directional antennas, reflections and swamped receivers make it hard to figure out just where the transmitter is. The solution is an attenuator, which simply reduces the signal to a more reasonable value. [Ryan] also used copper clad PCB for his circuit. Since the attenuator parts are soldered directly to the PCB, this is more of a Manhattan style design. Two ceramic 1k pots help him achieve his goal of near perfect linear attenuation. We’re betting this attenuator will help [Ryan] win some contests!

psdrWho says amateur radio won’t take you places? It may well be taking [Michael R Colton] to space! [Michael’s] project PortableSDR is one of the five finalists in The Hackaday Prize. We covered Michael earlier in the contest. PortableSDR started as a ham radio project: a radio system which would be easy for hams to take with them on backpacking trips. It’s grown into so much more now, with software defined radio reception and transmission, vector network analysis, antenna analysis, GPS, and a host of other features. We seriously love how [Michael] optimized a small LCD for waterfall display, tuning, and bandpass filter adjustment.

e2ra[W5VO] is working on an Ethernet to Radio Adapter. Every foot of coax in a radio system loses signal. Connections are even worse. It can all add up to several dB loss. [W5VO] wants to put an SDR at the antenna feed-point. With the signal path minimized, more watts make it out when transmitting, and more signal gets back to the receiver when listening. The interface between the SDR and host computer will be all digital; Ethernet to be precise. [W5VO] isn’t the first person to do something like this, microwave systems have had the transmitter and LNB at the antenna for years. That doesn’t take away from [W5VO’s] design at all  He’s been quiet for a while, but we’re hoping he continues on his design!

Where is everyone else? We’re a bit light on projects this week, but we have a good reason. There just aren’t enough ham radio projects on Hackaday.io! We’re hoping to change that though. Are you an amateur radio enthusiast? Document your project on the site. Get input from other hams and push the envelope! You might even find yourself on the Ham Radio List!

That’s all for this episode of The Hacklet. As always, QRX is next week. Same hack time, same hack channel, bringing you the best of Hackaday.io! 73’s!

Dots and Dashes… on a Roll!

morse code device

Morse code was once a staple of the communications industry, but with advancing technology it has become relegated almost exclusively to movies and a niche group of ham radio operators. [Jan] has created a device which might not put a stop to this trend, but will at least educate children on the basics of how Morse code works by visually displaying Morse code as it’s generated.

The setup is fairly simple. An old momentary switch (which could easily be used in an actual Morse code setup) activates two pieces of circuitry. The first is a 555 timer circuit that creates an audible tone when the switch is pressed so the user can hear exactly what an operator would hear when decoding a real Morse code message.

The second piece of circuitry is where the real genius lies: a continuously spinning roll of glow-in-the-dark tape is placed in front of a white LED. When the switch is pressed, the LED turns on, which produces dots and dashes on the roll of tape as it passes by. This eliminates the need for rolls of paper or a more complicated moving pen/pencil setup to draw on the paper which might also be less child-proof.

While [Jan] built this as a toy, the children who used it thoroughly enjoyed it! They even decoded some Morse code messages and used the device to practice on it. After a while they’ll easily be able to master the Morse code trainer!

Fishing for Radio Signals With the Moxon Antenna

mox-antenna

[Bill Meara] has finished his latest project, a Moxon antenna for HF on 17 meters. [Bill] is well-known here on Hackaday. When not building awesome radios, he can be found ranting about ham radio. His new antenna turned out to be a true hack. He even used a hacksaw to build it!

The Moxon antenna is named for the late [Les Moxon, G6XN] who first described it in “Two-Element Driven Arrays”, a QST magazine article published in July of 1952.  [Bill] built his Moxon loosely based on [Jim/AE6AC’s] excellent instructions. The design is incredibly simple – a two element directional antenna using crappie fishing poles as spreaders. That’s crappie as in the fish, not the quality of the pole. Crappie poles are typically made up of telescoping sections of graphite or fiberglass  in common lengths of 14, 16, and 20 feet. The poles can be bought for under $20 at sporting goods stores. [Bill] used 16 foot poles purchased from Amazon.

The antenna is created by connecting all four poles at their bases in an X shape. The wire elements are stretched across the ends of the poles. The entire antenna bends up as the stiff poles hold the driven and reflector elements in tension. [Bill] used some scrap wood and U-bolts to attach the fishing poles, and bungee cord ends at the tips. Since the antenna is directional, [Bill] added a TV antenna rotor to spin the beam around. The antenna is so light that one could get by with a couple of cords and the “Armstrong method” of antenna rotation.

Once up on the roof, [Bill] found his antenna really performed. He was easily able to cross the Atlantic from his Northern Virginia home to France, Belgium, and Latvia. The mostly horizontal antenna makes it a bit more unobtrusive than other directional designs. [Bill] mentions that his neighbors haven’t revolted yet, so he’s continuing to enjoy the fruits of his antenna labors.

Oinker is Twitter for HAMs

oinker

Have you ever wanted to send a quick message to your HAM radio buddies over the air but then realized you forgot your radio at home? [Troy] created Oinker to remedy this problem. Oinker is a Perl script that turns emails into audio.

The script monitors an email account for new messages and then uses the Festival text-to-speech engine to transform the text into audio. [Troy] runs Oinker on a Raspberry Pi, with the Pi’s audio output plugged directly into an inexpensive ham radio. The radio is then manually tuned to the desired transmit frequency. Whenever Oinker see’s a new email, that message is converted into speech and then output to the transmitter.

The script automatically appends your HAM radio call sign to the end of every message to ensure you stay within FCC regulations. Now whenever [Troy] runs into some bad traffic on the road, he can send a quick SMS to his email address and warn his HAM radio buddies to stay clear of the area.

Improve Your HT Ham Radio by Adding a Counterpoise Antenna Wire

counterpoise

We found an interesting tip that might just improve the performance of those small affordable handheld ham radios called a “Handy Talky” or HT for short in ham vernacular. [RadioHamGuy] posted an interesting video on adding a counterpoise antenna wire to an HT. He claims it will noticeably improve both transmit and receive by making a quarter-wave monopole into a makeshift dipole antenna system.

Per his instructions you basically add a short wire to the antenna’s outer ground connection or to an equivalent case screw that’s electrically connected to the antenna’s ground side. Apparently this can be referred to as a Tiger Tail and does make it look like your HT has a tail. You would construct a counterpoise antenna wire 11.5 inch for VHF, 6.5 for UHF and about 19.5 inches for an OK performing dual band VHF/UHF radio.

Normally with a handheld radio the counterpoise (ground) is your own body as you are holding the HT. This is because the capacitance of your body makes a good counterpoise under normal conditions. It would be interesting to hear what others find for performance when adding a counterpoise antenna wire.

You can watch [RadioHamGuy’s] full construction tutorial video for multiple radio types after the break.

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