Amateur Radio Transmits 1000 Miles On Voice Power

Many of us tried the old “Two tin cans connected by a string” experiment as kids. [Michael Rainey, AA1TJ] never quite forgot it.  Back in 2009, he built “El Silbo”, a ham radio transmitter powered entirely by his voice. El Silbo is a Double Side Band (DSB) transmitter for 75 meters. While voice is used to excite the transmitter, it doesn’t actually transmit voice. El Silbo is a CW affair, so you should bone up on your Morse Code a bit before building one. Like many QRP transmitters El Silbo’s circuit is rather simple. A junk box loudspeaker is installed at the bottom of the can to convert voice power to electrical power. The signal is passed through a step up transformer, and used to excite a 75m crystal. Two NPN transistors (in this case MPS6521) pass the signal on through a second transformer. The signal is then routed through an LC network to the antenna.

Back in 2009, [Michael] brought El Silbo to the Maine coast in an attempt to make a transatlantic contact. This isn’t as far-fetched as it sounds – [Michael] has “crossed the pond” on less power. While the attempt wasn’t successful, [Michael] has made connections as far as 1486km, or 923 miles. That’s quite a distance for simply yelling into a tin can! One of [Michael’s] favorite El Silbo stories is a 109KM conversation (QSO) he had with W1PID. [Michael] found that the signal was so good, he didn’t have to yell at all. He reduced power by dropping to his normal speaking voice for the “dits and dahs”. The two were able to converse for 17 minutes with [Michael] only using his speaking voice for power. We think this is an amazing achievement, and once more proof that you don’t need a multi-thousand dollar shack to make contacts as a ham.

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Telegraph sounder clicks out email messages

telegraph-box-together

[Patrick Schless] is excited to show off the project he took on about nine months ago. After finding an antique telegraph sounder he wired it up to an Arduino to see if he could make it tick. The successful experiment laid the ground work for different hardware that would make it into a morse code email reader.

He doesn’t know much about the background of the old hardware, but driving it is relatively simple. It’s basically a magnetic relay so you need to have a transistor for switching and a flyback diode for protection. Once those components are in place it’s just a matter of toggling a bit. [Patrick] knew he wanted to pull messages from an online source, so he set his Arduino aside and grabbed a Raspberry Pi. It worked like a charm. His plan was to put this on a bookshelf in perpetuity so he went the extra mile, designing his own PCB and having it spun using the OSH Park service. The project is finished with this low-profile laser-cut base which houses all of the electronics.

Now if he wants to respond to his emails in Morse code he needs to build this keyboard.

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Raspberry Pi used as a beacon transmitter

rpi-beacon-transmitter

[m0xpd] got his hands on an inexpensive AD9850 DDS Module from eBay but needed a way to control it. He took inspiration from the projects that used a PIC microcontroller, but decided to add his own twist by using a Raspberry Pi to build a multi-mode beacon transmitter.

At the center of this breadboarded circuit lies the green AD9850 module. To its left is a level converter he built to get the 3.3V levels from the RPi board to work with the rest of the 5V hardware. The signal then feeds into a QRP amplifier and a low pass filter.

He didn’t start from square one when it came time to write the code for the RPi. Instead he grabbed an Arduino sketch for the very same DDS and ported it over to Python. The first test signal was his call sign sent in Morse code at QRSS speeds. But he also managed to get Hellschreiber messages working, making it a multiple-mode device.

[via Solder Smoke]

Arduino using a straight key for Morse code assistance

arduino-morse-code-straight-key

For those unfamiliar with Ham Radio, there are lots of fancy tools these days to make it easier for the radio operator. But enthusiasts still like to get back to basics, and one way to do this is to participate in Straight Key Night. This is when you pull out your traditional Morse code keyer and have a chat with others around the world. The most recent event was on New Year’s Eve. The only drag is that it sometimes takes a while to find another Ham who’s listening, and this can mean repetitively keying the letters QC SKN for long periods of time (QC invites listeners to respond, and SKN is to inform them you’re participating in Straight Key Night). Sure, a programmable keyer will do this for you, but that is against the spirit of the event. [Mike Herr] found a grey area by mechanically interfacing an Arduino with a straight key.

You can see the straight key being pressed by a hobby servo in the image above. The servo is driven by the Arduino, which will transmit the series of letters automatically. As you can see in the video after the break, once [Mike] hears back from a fellow operator he switches to a huge wooden straight key for the rest of the conversation.

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Tie tack sends Morse code seasons greetings

morse-code-tie-tack

For [Davide Gironi] made a holiday tie tack this year. It’s not made to look like Santa Claus, Frosty, or a Christmas tree. He simply wishes you a Merry Christmas (‘Buon Natale’ in Italian) by flashing the message in Morse code.

Two LEDs have been added to a plain tie tack. It is tethered to the logic circuitry that provides power and drives the red and blue lights accordingly. As you can see in the video after the break, red signifies the end of a letter, and long or short blue flashes correspond to dashes or dots. This doesn’t require much horsepower so he’s gone with an 8-pin ATtiny13 microcontroller (you might be able to find one of these in a light bulb if you look hard enough). The rest of the equipment includes a few resistors, a push button, and a coin cell for power. [Davide] uses a byte-packing technique he learned from a different project to store each letter as an 8-bit packet which means there’s plenty of room to store your message in the chip’s memory.

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Morse code flower is trying to tell you something

morse-code-flower

To the casual observer this flower looks nice as its illuminated center fades in and out. But there’s hidden meaning to that light. Some of the blinks are longer than others; this flower is using Morse Code.

[Renaud Schleck] wanted to try a few different things with his MSP430 microcontroller. He decided on an LED that looks like a flower as it will be a nice piece of decor to set around the home. To add the Morse Code message he wanted something a bit more eloquent (and less distracting) than purely digital flashing. So he took the dots and dashes of the hard-coded message and turned them into fading signals by using Pulse-Width Modulation.

He free-formed the circuit so that it, and the coin cell that powers it, would fit in the flower pot. A reed switch is responsible for turning the juice on and off. When placed near a magnet the flower begins its gentle playback.

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Observe a satellite’s Morse Code message today!

Niwaka1-satellite

If you live in the Eastern portion of the United States and the skies are clear you can see a student built satellite flashing LEDs in Morse Code today. But don’t worry. If you it’s cloudy or if you live elsewhere there are several other opportunities to see it in the coming days.

This is the Niwaka Fitsat-1. It was developed by students at the [Fukuoka Institute of Technology] and deployed from the International Space Station on October 4th. Included in the payload is an array of LEDs seen in the image above. On a set schedule these are used to flash a Morse Code message for two minutes at a time. That is what’s shown in the image on the upper right.

You can look up information on seeing Fitsat-1 in your own area using this webpage. All of the observation windows in our area require a pair of binoculars or better. We’re not sure if there is any case in which this can be seen by the naked eye.

[Thanks SWHarden and KomradBob]