PI4ZLB

Radio waves travel fast, and they can bounce, too. If you are able to operate a 25-meter dish, a transmitter, a solid software-defined radio, and an atomic clock, the answer is: yes, they can go all the way to Venus and back. On March 22, 2025, the Dwingeloo telescope in the Netherlands successfully pulled off an Earth-Venus-Earth (EVE) bounce, making them the second group of amateurs ever to do so. The full breakdown of this feat is available in their write-up here.

Bouncing signals off planets isn’t new. NASA has been at it since the 1960s – but amateur radio astronomers have far fewer toys to play with. Before Dwingeloo’s success, AMSAT-DL achieved the only known amateur EVE bounce back in 2009. This time, the Dwingeloo team transmitted a 278-second tone at 1299.5 MHz, with the round trip to Venus taking about 280 seconds. Stockert’s radio telescope in Germany also picked up the returning echo, stronger than Dwingeloo’s own, due to its more sensitive receiving setup.

Post-processing wasn’t easy either. Doppler shift corrections had to be applied, and the received signal was split into 1 Hz frequency bins. The resulting detections clocked in at 5.4 sigma for Dwingeloo alone, 8.5 sigma for Stockert’s recording, and 9.2 sigma when combining both datasets. A clear signal, loud and proud, straight from Venus’ surface.

The experiment was cut short when Dwingeloo’s transmitter started failing after four successful bounces. More complex signal modulations will have to wait for the next Venus conjunction in October 2026. Until then, you can read our previously published article on achievements of the Dwingeloo telescope.

Surely by now you’ve at least heard of RTL-SDR — a software project that let’s cheap TV tuner dongles work as a software-defined radios. A number of projects and tools have spun off the original effort, but in his latest video, [Tech Minds] shows off a particularly unique take. It’s a Web browser-based radio application that uses WebUSB, so it doesn’t require the installation of any application software. You can see the program operating in the video below.

There are a few things you should know. First, you need the correct USB drivers for your RTL-SDR. Second, your browser must support WebUSB, of course. Practically, that means you need a Chromium-type browser. You may have to configure your system to allow raw access to the USB port, too.

Watching the video, you can see that it works quite well. According to the comments, it will work with a phone, too, which is an interesting idea. The actual Web application is available as open source. It isn’t going to compete with a full-fledged SDR program, but it looked surprisingly complete.

These devices have grown from a curiosity to a major part of radio hacking over the years. Firefox users can’t use WebUSB — well, not directly, anyway.

When your homebrew Yagi antenna only sort-of works, or when your WiFi cantenna seems moody on rainy days, we can assure you: it is not only you. You can stop doubting yourself once and for all after you’ve watched the Tech 101: Antennas webinar by [Dr. Jonathan Chisum].

[Jonathan] breaks it all down in a way that makes you want to rip out your old antenna and start fresh. It goes further than textbook theory; it’s the kind of knowledge defense techs use for real electronic warfare. And since it’s out there in bite-sized chunks, we hackers can easily put it to good use.

The key takeaway is that antenna size matters. Basically, it’s all about wavelength, and [Jonathan] hammers home how tuning antenna dimensions to your target frequency makes or breaks your signal. Whether you’re into omnis (for example, for 360-degree drone control) or laser-focused directional antennas for secret backyard links, this is juicy stuff.

If you’re serious about getting into RF hacking, watch this webinar. Then dig up that Yagi build, and be sure to send us your best antenna hacks.

[Tech Minds] built one of those cheap automatic antenna tuners you see everywhere — this one scaled up to 350 watt capability. The kit is mostly built, but you do have to add the connectors and a few other stray bits. You can see how he did it in the video below.

What was very interesting, however, was that it wasn’t able to do a very good job tuning a wire antenna across the ham bands, and he asks for your help on what he should try to make things better.

It did seem to work in some cases, and changing the length of the wire changed the results, so we would guess some of it might be a resonance on the antenna wire. However, you would guess it could do a little better. It is well known that if a wire is one of a number of certain lengths, it will have extremely high impedence in multiple ham bands and be challenging to tune. So random wires need to not be exactly random. You have to avoid those lengths.

In addition, we were surprised there wasn’t more RF protection on the power lines. We would probably have suggested winding some coax to act as a shield choke, RF beads, and even extra bypass capacitors.

Another possible problem is that the diodes in these units are often not the best. [PU1OWL] talks about that in another video and bypasses some of the power lines against RF, too.

If you have any advice, we are sure he’d love to hear it. As [PU1OWL] points out, a tuner like this can’t be any better than its SWR measurement mechanism. Of course, all of these tuners take a few watts to light them up. You can, however, tune with virtually no power with a VNA.

There’s something magical about the clunk of a heavy 1950s portable radio – the solid thunk of Bakelite, the warm hum of tubes glowing to life. This is exactly why [Ken’s Lab] took on the restoration of a Philco 52-664, a portable AC/DC radio originally sold for $45 in 1953 (a small fortune back then!). Despite its beat-up exterior and faulty guts, [Ken] methodically restored it to working condition. His video details every crackling capacitor and crusty resistor he replaced, and it’s pure catnip for any hacker with a soft spot for analog tech. Does the name Philco ring a bell? Lately, we did cover the restoration of a 1958 Philco Predicta television.

What sets this radio hack apart? To begin with, [Ken] kept the restoration authentic, repurposing original capacitor cans and using era-appropriate materials – right down to boiling out old electrolytics in his wife’s discarded cooking pot. But, he went further. Lacking the space for modern components, [Ken] fabbed up a custom mounting solution from stiff styrofoam, fibreboard, and all-purpose glue. He even re-routed the B-wiring with creative terminal hacks. It’s a masterclass in patience, precision, and resourcefulness.

If this tickles your inner tinkerer, don’t miss out on the full video. It’s like stepping into a time machine.

[MSylvain59] likes to tear down old surplus, and in the video below, he takes apart a German transceiver known as a U-600M. From the outside, it looks like an unremarkable gray box, especially since it is supposed to work with a remote unit, so there’s very little on the outside other than connectors. Inside, though, there’s plenty to see and even a few surprises.

Inside is a neatly built RF circuit with obviously shielded compartments. In addition to a configurable power supply, the radio has modules that allow configuration to different frequencies. One of the odder components is a large metal cylinder marked MF450-1900. This appears to be a mechanical filter. There are also a number of unusual parts like dogbone capacitors and tons of trimmer capacitors.

The plug-in modules are especially dense and interesting. In particular, some of the boards are different from some of the others. It is an interesting design from a time predating broadband digital synthesis techniques.

While this transceiver is stuffed with parts, it probably performs quite well. However, transceivers can be simple. Even more so if you throw in an SDR chip.

As part of the payloads on the Firefly Blue Ghost Mission 1 (BGM1) that recently touched down on the Moon, the Lunar GNNS Receiver Experiment (LuGRE) has become the first practical demonstration of acquiring and tracking Earth orbital GNSS satellites. LuGRE consists of a weak-signal GNSS receiver, a high-gain L-band patch antenna the requisite amplification and filter circuits, designed to track a number of GPS and Galileo signals.

Designed by NASA and the Italian Space Agency (ISA), the LuGRE payload’s goal was to demonstrate GNSS-based positioning, navigation and timing at the Moon. This successful demonstration makes it plausible that future lunar missions, whether in orbit or on the surface, could use Earth’s GNSS satellites to navigate and position themselves with. On the way to the lunar surface, LuGRE confirmed being able to track GNSS at various distances from the Earth.

Both LuGRE and BGM1 are part of NASA’s Commercial Lunar Payload Services (CLPS) program, with BGM1 delivering a total of ten payloads to the Moon, each designed to study a different aspect of the lunar environment, as well as hardware and technologies relevant to future missions.

Saying farewell is hard, and in the case of the Voyager 1 & 2 spacecraft doubly so, seeing as how they have been with us for more than 47 years. From the highs of the 1970s and 1980s during their primary mission in our Solar System, to their journey into the unknown of Deep Space, every bit of information which their instruments record and send back is something unique that we could not obtain any other way. Yet with the shutting down of two more instruments, both spacecraft are now getting awfully close to the end of their extended missions.

Last February 25 the cosmic ray system (CRS) on Voyager 1 was disabled, with the Low Energy Charged Particle Instrument (LECP) on Voyager 2 to follow on March 24. With each spacecraft losing about 4 watts of available power per year from their RTGs, the next few instruments to be turned off are already known. Voyager 1’s LECP will be turned off next year, with that same year Voyager 2’s CRS also getting disabled.

This would leave both spacecraft with only their magnetometer (MAG) and plasma wave subsystem (PWS). These provide data on the local magnetic field and electron density, respectively, with at least one of these instruments on each spacecraft likely to remain active until the end of this decade, possibly into the next. With some luck both spacecraft will see their 50th birthday before humanity’s only presence in Deep Space falls silent.

Thanks to [Mark Stevens] for the tip.

We used to say that fixing something was easier than bringing up a design for the first time. After all, the thing you are fixing, presumably, worked at one time or another. These days, that’s not always true as fixing modern gear can be quite a challenge. Watching [Ken’s] repair of an old 1955 Silvertone radio reminded us of a simpler time. You can watch the action on the video below.

If you’ve never had the pleasure of working on an AM radio, you should definitely try it. Some people would use an amplifier to find where the signal dies out. Others will inject a signal into the radio to find where it stops. A good strategy is to start at the volume control and decide if it is before or after that. Then split the apparently bad section roughly in half and test that portion—sort of a hardware binary search. Of course, your first step should probably be to verify power, but after that, the hunt is on.

There’s something very satisfying about taking a dead radio and then hearing it come to life on your bench. In this case, some of the problems were from a previous repair.

Troubleshooting is an art all by itself. Restoring old radios is also great fun.