ham radio

224 Articles

Quick Hack Disables IPod Dock Auto-standby

May 2, 2011 by 11 Comments

ipod_dock_hacking

[Aaron] wrote in to share with us a quick hack that has made his life a little easier. He bought a Rocketfish RF-HV3 portable iPod dock to listen to his music, but he wanted to utilize it as an alarm clock as well. He also found that the speakers worked quite well when he hooked up his Yaesu handheld transmitter to the dock.

The only problem he had with it was that the dock would automatically power down when there was no input for 5 minutes. That’s fine when the dock is running on batteries, but if [Aaron] was going to use it as an alarm clock or to listen to his HAM radio, that simply wouldn’t do.

He pulled the dock apart and started poking around with his DSO Nano scope. He found that if pin 16 stays low for 5 minutes, it turns off the dock even if there is a signal coming through. His fix for the problem was actually quite simple – all he did was solder the VDD pin to the pin in question, and the 5-minute timeout was disabled.

We’re glad that [Aaron] was able to solve his problem in such an easy manner – it just goes to show what you can do with a scope and a few minutes’ time.

PIC-based Ham Radio Autotuner

April 7, 2011 by 6 Comments

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A few years back, [Floyd, K8AC] built a high frequency autotuner as an addition to his Ham radio setup. Based off a design he saw in QST magazine back in the early ’90s, he has been using the tuner almost daily for the last few years, on both the 3.5 MHz and 7 MHz bands.

Built into the wall in his radio room, it is a pretty impressive sight. His “L” circuit is controlled by a pair of mechanically coupled inductors which are driven in concert by a pair of two-way motors. The positioning of the C and L components are monitored by a PIC controller which stores the tuning data for up to 30 predefined frequencies. A couple of button presses on his controller’s front end sends the tuner into action, dialing in his unit’s inductors and capacitor to their proper settings. The PIC monitors the tuner’s progress, informing him when the proper frequency has been tuned in, or if the frequency can not be set, indicating issues with the equipment.

His setup has undergone several revisions over the years, with the most recent iteration being the most automated of the bunch. Check out his site for plenty more details, or keep an ear out for [K8AC] on 40 or 80 meters.

[Thanks, Rich V]

Launchpad Serial Morse Code Transmitter

February 11, 2011 by 11 Comments

LaunchPad-Serial-Morse-Transmitter

LaunchPad dev boards from Texas Instruments are cheap and easy to program, making them a great Arduino alternative if you can do without some of the bells and whistles. [ech0s] put his to good use by constructing a Morse code transmitter with dual operating modes. The transmitter can not only encode and transmit messages entered in a terminal client, it also allows the user to send messages by manually operating the key switch. Inspired by the high altitude balloon transmitter we featured last summer, this project uses similar components for signal amplification and transmission. Text can be entered in a Putty terminal window, which then is encoded into Morse by the MCU before transmission. At the moment, the speed of the radio transmission is about 15 WPM, which is reasonably quick. Even though his system performs quite well [ech0s] has some improvements planned, including having a proper PCB built as well as some software tweaks to improve buffering and bandwidth. Be sure to check out his video of the transmitter in action after the jump.

Continue reading “Launchpad Serial Morse Code Transmitter” →

Building A Window Mounted Antenna For Your Car

April 12, 2010 by 16 Comments

If you’re into ham radio and want it when you’re on the go give this antenna mount a try. [Cirictech] started with a design from the November 2009 issue of QST and added his own fabrication touches. Everything except the antenna itself is available from the hardware store for just a few bucks, and you should be able to complete this project in a flash. This makes us wonder what the antenna for the 47 GHz band radio setup would look like.

WSPRing Across The Atlantic

May 7, 2009 by 30 Comments

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Host of the Soldersmoke podcast, [Bill Meara], contributed this guest post.

WSPR is a new communications protocol written by radio amateur and Nobel Prize winner [Joe Taylor]. Like the very slow QRSS system described in a previous post, WSPR (Weak Signal Propagation Reporter) trades speed for bandwidth and allows for the reception of signals that are far below the level of radio noise. WSPR takes “low and slow” communications several important steps ahead, featuring strong error correction, high reliability, and (and this is really fun part) the automatic uploading (via the net) of reception reports — [Taylor]’s WSPR web page constantly gathers reports and produces near real-time Google maps of showing who is hearing who. The WSPR mode is very hack-able: [Bill Meara] is running a 20 milliwatt homebrew transmitter from Rome, Italy that features an audio amplifier from a defunct computer speaker pictured below. This contraption recently crossed the Atlantic and was picked up by the Princeton, New Jersey receiving station of WSPR’s esteemed creator, [Joe Taylor]. Continue reading “WSPRing Across The Atlantic” →