BITX, A Return to Hackers’ Paradise


[Bill Meara] has finished up his radio. It both looks and sounds great. It was only a few weeks ago that [Bill] posted a guest rant here on Hackaday. The Radio he mentioned building in the rant is now complete. The transceiver itself is a BITX, a 14MHz Single Sideband (SSB) radio designed by Ashhar Farhan VU2ESE. Ashhar designed the BITX as a cheap to build, and easy to tune up transceiver for radio amateurs in India.

By utilizing parts easily sourced from scrapped TV sets, the BITX can be built for less than 300 Indian Rupee – or about $4.70 USD. In [Bill]’s own words, “Five bucks and some sweat equity gets you a device capable of worldwide communication.” He’s not kidding either. [Bill’s] first QSO was with a ham in the Azores Islands of Portugal.

[Bill] built his radio using the “Manhattan” building style, which we’ve seen before. Manhattan style uses rectangular pads glued down onto a copper ground plane. It makes for a more flexible design than regular old dead bug style building. Looking at all those components may be a bit daunting at first, but plenty of support is available. [Bill] has an 18 part build log on the soldersmoke website. There also is an active yahoo group dedicated to the BITX.

Diagnose and Repair a Yaesu FT-7800 Ham Radio

Yaesu FT-7800 Ham Radio

[Alan Wolke] aka [w2aew] was challenged to repair a friends Yaesu FT-7800 ham radio. This radio operates on two ham bands, 2 m VHF and 70 cm UHF. The complaint was that the 2 m side was not working but the 70 cm was transmitting fine. Alan started by verifying the complaint using a Bird watt meter with a 50 watt slug and terminating the signal into a 50 W dummy load. [Allen’s] bird meter is the type that has an RF sampler that can be connected to an oscilloscope for added signal viewing and validation.

After verifying that the radio was not working as described, Alan starts by glancing over the circuit board to look for any obvious damage. He then walks us through a block diagram as well as a circuit diagram of the FT-7800 radio before stepping us through the troubleshooting and diagnostics of radio repair. Even when he realizes he might have found the problem he still steps us through the remainder of his diagnostics. The skills and knowledge that Alan shares is extremely valuable to anybody looking to repair radios.

Spoiler alert. At the end of the first video he determines that the pin diodes near the final VHF output were bad. In the second video he reveals that he could no longer source these bad components. Through some clever evaluation of a more current Yaesu radio, [Allen] was able to find suitable replacement components. Lesson two ends with some surface mount solder rework tips as well as testing that the repair was successful.

And just in case you don’t know what a pin diode is, or is used for, Alan shares a third video covering just what this component is and does in a radio. You can follow the jump to watch all three videos.

[Read more...]

Guest Rant: Ham Radio — Hackers’ Paradise


Editor’s Note: This is a guest post written by [Bill Meara]

The suits at Hack-a-Day reached out to SolderSmoke HQ and asked me to send in a few words about why their readers should take a fresh look at ham radio. Here goes:

First, realize that today’s ham radio represents a tremendous opportunity for technical exploration and adventure. How about building a station (and software) that will allow you to communicate by bouncing digital signals off the moon? How about developing a new modulation scheme to send packets not down the fiber optic network, but around the world via the ionosphere, or via ham radio’s fleet of satellites? How about bouncing your packets off the trails left by meteors? This is not your grandfather’s ham radio.

You can meet some amazing people in this hobby: Using a very hacked-together radio station (my antenna was made from scrap lumber and copper refrigerator tubing) I’ve spoken to astronaut hams on space stations. Our “low power, slow signal” group includes a ham named Joe Taylor. Joe is a radio astronomer who won the Nobel Prize for Physics. He’s now putting his software skills to use in the development of below-the-noise receiving systems for ham radio. Join me after the break for more on the topic. [Read more...]

Turning an easter egg hunt into a fox hunt


We’ve seen [Todd Harrison]‘s work a few times before, but he’s never involved his son so throughly before. This past Easter, he thought it would be a good idea for his son and a few of his friends to take part in an easter egg hunt. Being the ham he is, he decided to turn an easter egg hunt into an adventure in radio direction finding, or as amateur radio operators call it, a fox hunt.

[Todd] put together a great tutorial on building a yagi – a simple directional antenna – out of a couple of pieces of PVC pipe and a few aluminum and brass rods. With this and a handheld ham set, [Todd] hid a fox along with a stuffed easter bunny and a basket of candy near a local park. Operating under the guidance of his dad, [Todd]‘s son and his friends were eventually able to find the fox. Leaving candy out in the Arizona sun probably wasn’t [Todd]‘s best idea – the fox, and candy, were covered in ants when they were found – but it was a great introduction to amateur radio.

Writing new firmware for a handheld radio


When playing around with a cheap, handheld, dual-band radio, [Lior], a.k.a. [KK6BWA], found a schematic for a similar and even cheaper radio. He realized the programming pads were very accessible and the dev tools for the radio’s microcontroller were available from the manufacturer. After these discoveries, there really was only one thing to do: write new firmware for a $40 radio, and making a great tool for playing around in the 2 meter and 70 cm bands.

The instructions for reflashing the firmware on this radio only require an Arduino and a handful of miscellaneous components. [Lior]‘s new firmware for the uv3r radio isn’t quite finished yet, but he plans on adding some really impressive features. Things like a better UI for a four-button radio, a mode for tracking satellites, a digital mode, and a computer-controlled mode are all possible and on [Lior]‘s project wishlist.

Getting a $40 radio to do your bidding with an Arduino is cool enough, but [Lior] says this mod for the uv3r can be taken even further: if you’ve got an amateur radio license, it’s possible to use the uv3r to control an Arduino or other microcontroller from miles away. It’s a great hack, right up there with the USB TV tuner/software defined radio thing we saw almost exactly one year ago.

You can check out a demo of some custom software running on the uv3r after the break. The radio listens for a DTMF tone (supplied by the uv3r’s big brother, the uv5r), and plays back a three-digit DTMF tone. There’s also a more through walk through of what [Lior]‘s new radio can do as well.

[Read more...]

WSPR transmitter shows true value of Raspberry Pi for hacking


Don’t get us wrong, we love our Raspberry Pi. But if you’re merely running a Linux image without adding a hardware hack into the mix you’re missing out on part of the power for which the platform was developed. This project is a great example of how to embrace the Raspberry Pi’s ability to deliver both low-level hardware access, and solid embedded Linux performance. [Dan Ankers] and [Threeme3] have developed a program which turns the RPi in to a WSPR transmitter. The GitHub readme shares many of the details on how it was done. But you’ll also want to dig through the .c file to see how they’re making use of the GPIO header pins.

[William Meara] sent in the tip for this. He’s been featured on Hackaday previously for his work with WSPR (Weak Signal Propagation Report). It’s an amateur radio protocol which lets you communicate over very long distances using relatively weak transmitters. The trick is to use computing power to find the signal hidden in all the noise. Be warned that you do need a HAM license to try this out, but otherwise all you need to connect to the board is a low-pass filter and an antennae.

[via SolderSmoke]

[Photo credit: WSPR hompage]

Arduino as an inexpensive ham radio frequency counter


[Todd Harrison] really has our number. Like him, we don’t want to spend money when we don’t have to, and hacking our own solutions is a lot more fun anyway. This time around he’s helping out a friend who is a ham radio enthusiast. The friend’s radio didn’t come with a frequency display, and buying the add-on would cost more than the radio did. So [Todd] has set out to build an Arduino frequency counter for a Kenwood TS-520S HF ham radio.

This post (and the video found after the break) doesn’t cover the entire project. It’s rather involved just to make sure that [Todd's] initial idea is viable so he spends about 35 minutes explaining the problem, then measuring the radio outputs and testing to see that the Arduino can read them accurately. Because the radio has a very large range of operation, [Todd] will need to add external component to facilitate this. That extra circuit design will be the topic of the next project segment.

[Read more...]


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