ham

132 Articles

This Packable Ham Radio Antenna Is Made From Nothing But Tape

October 13, 2023 by 46 Comments

On today’s episode of “Will It Antenna?”, [Ben Eadie (VE6SFX)] designs and tests an antenna made entirely of tape, and spoiler alert — it works pretty well.

By way of background, the basic design [Ben] uses here is known as a J-pole, a popular “my first antenna” design for amateur radio operators looking to go beyond the stock whip antenna that comes with that cheap handy-talkie you just can’t resist buying as soon as you get your license. Usually, though, hams will build their J-poles from rigid materials, copper water pipe being a typical choice. Copper has the advantage of being easily sourced, and also results in a self-supporting, weather-resistant antenna that’s easy to mount outdoors. However, copper is getting to be egregiously expensive, and a couple of meters of water pipe isn’t exactly amenable to portable operation, if that’s your jam.

To solve those problems, [Ben] decided to keep his copper use to a minimum with a roll of copper foil tape. He doesn’t provide any specs on the tape, but it looks like it’s about 6 mm (1/4″) wide and judging by a quick Amazon search, probably goes for about $10 a roll. He starts the build with a couple of strips of plain old duck tape — we’ve already had the “duck vs. duct” argument — laid out with the sticky sides together. The copper foil is applied to the duck tape backing using dimensions from any of the J-pole calculators available online. Dimensions are critical to getting good performance from a J-pole, and this is where [Ben]’s tape design shines. Element too long? No problem, just peel up a bit and tear some off. Did you go too far and make an element too short? Easy — just stick on an extension piece of foil. Tuning the location of the feedline connection was a snap, too, with movable terminals held in place with magnets.

Once everything was tuned up, [Ben] soldered down the feed points and covered the foil with a protective layer of duck tape. The antenna performed swimmingly, and aside from costing almost nothing to build, it weighs very little, rolls up to fit in a pack for field operations, and can easily be hoisted into a tree for better coverage. Looks like we’ll be putting in an order for some copper tape and building one of these too. Continue reading “This Packable Ham Radio Antenna Is Made From Nothing But Tape” →

Altoids Tin Spy Radio Goes Solid State

September 21, 2023 by 9 Comments

[Helge Fykse (LA6NCA)] has a type, as they say. At least as far as radios are concerned, he seems to prefer elegant designs that keep the BOM to the minimum needed to get the job done. And Altoids tins — he really seems to like putting radios in Altoids tins.

This QRP transceiver for the 60-meter amateur radio band is a perfect example of that ethos. For the unfamiliar, QRP is Morse code shorthand for decreased power, and is generally used when hams are purposely building and operating radios that radiate very little power, typically below a watt. For this transceiver, [Helge] chose to use modern components, a marked but interesting departure from his recent tube-powered spy radios. The design is centered on a custom oscillator board he designed using an Arduino Pro Mini and an Si5351 oscillator chip. Other components include an ADE-1ASK frequency mixer, an antenna tuner module that can be swapped out for operating on different bands, a receiver that’s little more than a couple of op-amps, and a Darlington pair for an RF power amplifier. Everything fits neatly on a piece of copper-clad board inside the tin box.

As is his tradition, [Helge] was on the air in the field with this radio almost before the solder had time to cool. His first contact was a 240-km shot to a friend, who reported a fine signal from this little gem. And that’s with just powering it off a 9-volt battery when it’s designed to the typical 12-volt supplies hams favor; he estimates this resulted in a signal of about 200 mW. Not too shabby.

Honestly, we’d love to learn more about that oscillator board [Helge] used, and maybe get a schematic for it. We found a little bit about it on his web page, but not the juicy details. If you’re out there, [Helge], please share the wealth.

Continue reading “Altoids Tin Spy Radio Goes Solid State” →

USB-C Power For Ham Radio

September 5, 2023 by 28 Comments

Even though manufacturers of handheld ham radios have been busy adding all sorts of bells and whistles into their portable offerings, for some reason, many of them lack a modern USB-C port. In the same vein, while some have USB for programming or otherwise communicating between the radio and a computer, very few can use USB for power. Instead , they rely on barrel jacks or antiquated charging cradles. If you’d like to modernize your handheld radio’s power source, take a look at what [jephthai] did to his Yaesu.

In the past, USB ports could be simply soldered onto a wire and used to power basically anything that took 5 VDC. But the radio in question needs 12 volts, so the key was to find a USB-C cable with the built-in electronics to negotiate the right amount of power from USB-PD devices. For this one, [jephthai] cut the barrel connector off his radio’s power supply and spliced in some Anderson power pole connectors so he could use either the standard radio charger or one spliced onto this special cable.

With this fairly simple modification out of the way, it’s possible to power the handheld radio for long outings with the proper USB battery bank on hand. For plenty of situations this is much preferable to toting around a 12 V battery, which was the method of choice for powering things like QRP rigs when operating off-grid.

All-Mechanical Coil Winder Is A Scrap-Bin Delight

August 30, 2023 by 10 Comments

If there’s something more tedious than winding coils, we’re not sure what it is — possibly rolling and wrapping coins; that’s really a bother. But luckily, just like there are mechanical ways to count coins, there are tools to make coil production a little less of a chore, but perhaps none that have as much charm as this all-mechanical coil winder.

We’d say that [Ralph (VK3ZZC)]’s amazing invention firmly falls under the “contraption” category, without a hint of the term being used as a pejorative. The rig was based on the MoReCo Coilmaster, a machine that was once commercially available at a fairly steep price, according to [Ralph], and still seems to command a premium even today. Never being able to afford an original, [Ralph] spun up his own from scrap metal and tooling no more sophisticated than a drill press. It’s a riot of brass and steel, with a hand crank that drives the main winding shaft while powering a cam that guides the wire along the long axis of the coil form. Cams can be changed out for different winding patterns, and various chucks adapt to hold different coil forms to the winding shaft.

Continue reading “All-Mechanical Coil Winder Is A Scrap-Bin Delight” →

Off-Grid Radio Also Repairable Off-Grid

August 19, 2023 by 30 Comments

Low-power radios, often referred to in the amateur radio community as QRP radios, have experienced a resurgence in popularity lately. Blame it on certain parts of the hobby become more popular, like Parks on the Air (POTA) or Summits on the Air (SOTA). These are events where a radio operator operates off-grid at remote parks or mountaintops. These QRP rigs are a practical and portable way to make contacts. You would think that a five- or ten-watt rig running on batteries would be simple. Surprisingly, they can be enormously complex and expensive. That’s why [Dr. Daniel Marks] built the RFBitBanger, a QRP radio designed to not only be usable off-grid but to be built and maintained off-grid as well.

The radio accomplishes this goal by being built out of as many standard off-the-shelf components as possible. It eschews modern surface-mount components in favor of the much more accessible through-hole parts, including the ATMEGA328P at the center of the build. A PCB design is also available, but it can be built on perf board nearly as easily. The radio supports any mode a QRP operator might use, including CW, SSB, RTTY, and a new mode designed explicitly for this radio called SCAMP which is a low bandwidth, low SNR digital mode built into the Arduino-based firmware. It’s a single-band radio, but any band between 20 and 80 meters can be selected with pluggable filters.

As far as bomb-proof radios go, we can’t imagine a better way to live out an apocalypse than with a radio like this. As long as there’s a well-stocked parts drawer around, this radio could theoretically reach around the world without worrying about warranty claims, expensive parts, or even a company going out of business or not stocking parts for old radios anymore. There’s also more information about this build at the Open Research Institute for those interested. And, if you’re wondering how useful any radio could be using only five watts of transmitter power, take a look at this in-depth look at QRP radio operation.

Thanks to [Stephen Walters] for the tip.

Bringing A Baofeng Into The Cyberpunk 2077 Universe

July 14, 2023 by 10 Comments

You’ve got to love the aesthetics of dystopian cyberpunk video games, where all the technology looks like it’s cobbled together from cast-off bits of the old world’s remains. Kudos go to those who attempt to recreate these virtual props and bring them into the real world, but our highest praise goes to those who not only make a game-realistic version of a prop, but make it actually work.

Take the Nokota Manufacturing radio from Cyberpunk 2077, for instance. [Taylor] took one look at that and knew it would be the perfect vessel for a Baofeng UV-5R, the dual-band transceiver that amateur radio operators love to hate. The idea is to strip the PCB out of a Baofeng — no worries, the things cost like $25 — and install it in a game-accurate 3D printed case. But this is far from just a case mod, since [Taylor]’s goal is to replace the radio’s original controls with something closer to what’s in the game.

To that end, [Taylor] is spinning up an interface to the stock radio’s keypad using some 7400-series bilateral analog switches. Hooked to the keypad contacts and controlled by a Mini MEGA 2560 microcontroller, the interface is able to send macros that imitate the keypresses necessary to change frequencies and control the radio’s settings, plus display the results on the yellow OLED screen that seems a dead-ringer for the in-game display. The video below shows some early testing of the interface.

While very much still a work in progress, we’ve been following [Taylor]’s project for a week or so and he’s really gaining some ground. We’ve encouraged him to enter this one in the Cyberdeck Challenge we’ve got going on now; it might not have much “deck” going for it, but it sure does have a lot of “cyber.”

Continue reading “Bringing A Baofeng Into The Cyberpunk 2077 Universe” →

Inexpensive Ham Radio Gets Upgrades Thanks To A Trojan

July 6, 2023 by 21 Comments

Love them or hate them, the crop of cheap hand-held amateur radio transceivers is here to stay. They’re generally horrible radios, often smearing spurious emissions across the spectrum, but they’re cheap enough to throw in a glove box for emergencies, and they invite experimentation — for instance, modifying the firmware to add functionality the OEM didn’t think to offer.

The new hotness in this class of radios is the Quansheng UV-K5, a two-band transceiver you can pick up for about $40, and we suspect it’ll get hotter still with this firmware trojan by [Piotr (SQ9P)]. We’ve already seen a firmware hack for these radios, one that aimed at unlocking the full frequency range of the RF chip at the heart of the radio. Honestly, we’re not huge fans of these mods, which potentially interfere with other allocations across multiple bands. But [Piotr]’s hacks seem a bit more innocuous, focusing mainly on modifying the radio’s display and adding useful features, such as a calibrated received signal strength bar graph and a numerical RSSI display. The really neat new feature, though, is the spectrum display, which shows activity across a 2-MHz slice of spectrum centered on the currently set frequency. And just because he could, [Piotr] put in a game of Pong.

[Piotr]’s description of the mod as a trojan seems apt since his new programs run in parallel to the OEM firmware by wrapping its vector table. We’d imagine other mods are possible, and we’re keen to see what people come up with for these hackable little units. Just make sure you’re staying within the law, especially in the United States — the FCC does not play games (third item).