Everything You Wanted To See About Restoring A 1956 Radio

October 16, 2022 by Donald Papp 13 Comments

Ever wanted a good, good look at the insides of a 1950s radio, along with fantastic commentary on the internals and the purpose of various components? Then don’t miss [Adam Wilson]’s repair and restoration of a 1956 Philips 353A, a task made easier by a digitized copy of the service manual. [Adam] provides loads of great pictures, as well as tips on what it takes to bring vintage electronics back to life. What’s not to like?

Vintage electronics like this are often chock-full of components that deteriorate with age, so one doesn’t simply apply power to see if it still works as a first step. These devices need to be inspected and serviced before power is ever applied. Even then, powerup should be done with a current-controlled source that can be shut down if anything seems amiss.

Thank goodness for high quality, digitized service manuals.

Devices like these largely predate printed circuit boards, so one can expect to see plenty of point-to-point soldering. Vacuum tubes did much of the hard work, so they are present instead of integrated circuits and transistors. Capacitors in the microfarads were much larger compared to their modern equivalents, and paper/wax capacitors (literally made from rolled-up paper covered in wax) handled capacitances in the nanofarad range instead of the little ceramic disk caps of today.

One thing that helped immensely is the previously-mentioned Philips 353A service manual, which includes not only a chassis and component layout, but even has servicing procedures such as cord replacement for the tuning dial. Back then, a tuning dial was an electromechanical assembly that used a winding of cord to rotate the tuning capacitor, and replacing it was a fiddly process. If only all hardware was documented so well!

The end result looks wonderful and still has great sound. As a final tweak, [Adam] added an external audio input cable as a nod to the modern age. Now, we have in the past seen a small LED screen integrated convincingly into an antique, but in this case [Adam] kept the original look completely intact. You can see it in action, playing some Frank Sinatra in the short video embedded below.
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TRX-Duo Is A Red Pitaya Clone For Software Defined Radio

October 9, 2022 by Al Williams 33 Comments

If you’ve noticed the TRX-DUO software-defined radio transceiver, you might have wondered how it stacks up to other choices like Red Pitaya or HackRF. [Tech Minds] obliges with a review of the Red device in the video below.

While this unit isn’t inexpensive, it also isn’t as expensive as some of its competitors. Sure, you can pick up an RTL-SDR dongle for a fraction of the price, but then you miss out on transmitting. The device is pretty powerful compared to a cheap software defined radio:

Frequency: 10 kHz to 60 MHz
CPU: Zynq SoC with a dual-core ARM Cortex A9
RAM: 512 MB
OS: Linux
Connectivity: Ethernet and USB connectivity (WiFi with a dongle)
ADC: 16-bit at 125 MS/s (2 channels)
DAC: 14-bit at 125 MS/s (2 channels)

The board boots off an SD card and there are several to choose from. The video shows two different images. One has a number of applications that run on the device and will also run on a Red Pitaya. The device shows a browser menu with various options and the result is quite impressive. Using the box as a WSPR beacon, it was heard fairly well given the low output power. It was, however, able to hear the world easily.

You can get a less capable Red Pitaya model for about $100 less than the going price. However, for something comparable, you will pay more for the Red Pitaya and — depending on capabilities — perhaps a lot more, although you do get more capability for the increased price.

You can do a lot more with a transmitting SDR — having both transmit and receive opens up many new projects. Of course, canned applications are great, but if you get one of these, you are going to want to try GNU Radio.

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DIy Arduino FM radio enclosure with the lid off, showing the electronics inside

DIY Arduino Due TEA5767 FM Radio

October 8, 2022 by Dave Walker 10 Comments

Older hackers will remember that a crystal set radio receiver was often one of the first projects attempted. Times have changed, but there’s still something magical about gathering invisible signals from the air and listening to the radio on a homemade receiver. [mircemk] has brought the idea right up to date by building an FM radio with an OLED display, controlled with a rotary encoder.

The design is fairly straightforward, based as it is on another project that [mircemk] found on another site, but the build looks very slick and would take pride of place on any hacker’s workbench. An Arduino Due forms the heart of the project, controlling a TEA5767 module, an SH1106 128×64 pixel OLED display and a rotary encoder. The sound signal is passed through an LM4811 headphone amplifier for private listening, and a PAM8403 Class D audio amplifier for the built-in loudspeaker. The enclosure is made from PVC panels, and accented with colored adhesive tape for style.

It’s easier than ever before to quickly put together projects like this by connecting pre-built modules and downloading code from the Internet, but that doesn’t mean it’s not a worthwhile way to improve your skills and make some useful devices like this one. There are so many resources available to us these days and standing on the shoulders of giants has always been a great way to see farther.

We’ve shown some other radio projects using Arduinos and the TEA5767 IC in the past, such as this one on a tidy custom PCB, and this one built into an old radio case.

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Building A Digital Library Of Amateur Radio And Communications

October 6, 2022 by Jenny List 8 Comments

For years the Internet Archive has provided the online community with a breathtaking collection of resources, out of print books, magazines, recordings, software, and any other imaginable digital asset in easily retrievable form. Now with the help of a grant from the Amateur Radio Digital Communications Foundation they are seeking to create a collection that documents amateur radio from its earliest days to the present.

The work will be multi-faceted, and include the print and digital materials we’d expect, as well as personal archives and oral histories from notable radio amateurs. For many of us this will provide a wealth of technical details and insights into taming the ionosphere, but for future historians it will be an invaluable reference on the first century of the hobby.

Amateur radio is perhaps the oldest hardware hacking pursuit of the electronic age, because certainly at the start, radio was electronics. Thus amateur radio’s long history has indirectly given us many of the things we take for granted today. Sure it has its moribund aspects, but we think if it continues to follow the growth of new technology as it has for so many years it will continue to be an exciting pursuit. We look forward to browsing this archive, and we hope to see it grow over the years.

Header image: Lescarboura, Austin C. (Austin Celestin), 1891-, No restrictions.

Snooping On Starlink With An RTL-SDR

September 23, 2022 by Dan Maloney 21 Comments

With an ever-growing constellation of Starlink satellites whizzing around over our heads, you might be getting the urge to start experimenting with the high-speed internet service. But at $100 or more a month plus hardware, the barrier to entry is just a little daunting for a lot of us. No worries, though — if all you’re interested in is tracking [Elon]’s birds, it’s actually a pretty simple job.

Now, we’re not claiming that you’ll be able to connect to Starlink and get internet service with this setup, of course, and neither is the delightfully named [saveitforparts]. Instead, his setup just receives the beacon signals from Starlink satellites, which is pretty interesting all by itself. The hardware consists of his “Picorder” mobile device, which sports a Raspberry Pi, a small LCD screen, and a host of sensors, including an RTL-SDR dongle. To pick up the satellite beacons, he used a dirt-cheap universal Ku-band LNB, or low-noise block downconverter. They’re normally found at the focal point of a satellite TV dish, but in this case no dish is needed — just power it up with a power injector and point it to the sky. The signals show up on the Picorder’s display in waterfall mode; curiously, the waterfall traces look quite similar to the patterns the satellites make in the night sky, much to the consternation of astronomers.

Of course, you don’t have to have a Picorder to snoop in on Starlink — any laptop and SDR should work, despite [saveitforparts]’ trouble in doing so. You shouldn’t have much trouble replicating the results by following the video below, which also has a few tips on powering an LNB for portable operations.

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Simple Internet Radio Transplant

September 22, 2022 by Jonathan Bennett 18 Comments

While we have a definite sweet spot in our hearts for analog radio, there are times that just call for a digital upgrade. One of the downsides that can come with this upgrade is complexity. For example, the more software-minded among us might base their build on the Music Player Daemon, and use a web interface for control. But that’s not everyone’s idea of a good time, and particularly an older user of your gizmos might really appreciate a simple, tactile user interface. That’s the situation [Blake Hannaford] was in, while building an Internet powered radio for someone else.

The solution was to take a familiar analog radio, the Tivoli Audio Model One, and give it a digital makeover. Now before you get worked up about wrecking the purity of a classic radio, note that the Model One is a faux-classic, made in 2000. No antiques were harmed in the making of this hack, and the exterior is essentially left stock — the only visible modification being the taped-on tuner label.

Inside it’s a Raspberry Pi Zero, the Adafruit Audio Bonnet, and a 3D printed bracket to tie a variable potentiometer to the tuning knob. The original volume knob and speaker are re-used. As [Blake] says, sometimes all you need is tuning and volume. Plus, re-using the speaker means that the whole unit still sounds great. Sometimes simple really is best.

While you’re here, check out our previous coverage of these style hacks and conversions!

AntRunner Is The Satellite Antenna Mount You Need To Take With You

September 17, 2022 by Jenny List 13 Comments

It stands to reason, that should you wish to communicate with a satellite, whatever antenna you use should point at that satellite. Some of us have done this by hand, following the bright dot of the space station in the night sky. Still, for anything more serious than trying to catch a fleeting SSTV image, a more robust solution is called for. In other words, a motorized antenna rotator, and AntRunner from [Wuxx] is just the ticket. Better still, it’s portable for those /p operating sessions off the beaten track.

The rotator itself is an az-el design with a couple of geared stepper motors. The full mechanism design has been published, but it shouldn’t be too difficult to copy. The interesting part is the controller and software, which can work with Gpredict, Hamlib, and SDR for automated satellite tracking. The controller is as straightforward as an ESP32 running the ESP port of GRBL.

So here’s a portable antenna rotator that’s accessible and widely supported, what’s not to like? As you might expect though, it’s not the first we’ve seen. In fact, the 2014 Hackaday Prize was won by SatNOGs, which includes a 3D printed antenna positioner.

Thanks [Abe Tusk] for the tip!