Hello From The NearSpace

November 9, 2020 by Matthew Carlson 6 Comments

A key challenge for any system headed up into the upper-atmosphere region sometimes called near space is communicating back down to the ground. The sensors and cameras onboard many high altitude balloons and satellites aren’t useful if the data they collect can’t be retrieved. Often times, custom antennas or beacons are added to help. Looking at the cost and difficulty of the problem, [arko] and [upaut] teamed up to try and make a turn-key solution for any near-space enthusiast by building CUBEX, a wonderful little module with sensors and clever radio that can be easily reused and repurposed.

CUBEX is meant as a payload for a high-altitude balloon with a camera, GPS, small battery, solar cell, and the accompanying power management circuits. The clever bit comes in the radio back down. By using the 434.460 Mhz band, it can broadcast around a hundred miles at 10mW. The only hardware to receive is a radio listener (a cheap RTL USB stick works nicely). Pictures and GPS coordinates stream down at 300 baud.

Their launch was quite successful and while they didn’t catch a solar eclipse, their balloon reached an impressive 33698m (110,560ft) while taking pictures. Even though it did eventually splashdown in the Pacific Ocean, they were able to enjoy a plethora of gorgeous photos thanks to their easy and cost-effective data link.

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Radio Remote Control Via HTML5

October 24, 2020 by Adam Zeloof 36 Comments

It’s a common scene: a dedicated radio amateur wakes up early in the morning, ambles over to their shack, and sits in the glow of vacuum tubes as they call CQ DX, trying to contact hams in time zones across the world. It’s also a common scene for the same ham to sit in the comfort of their living room, sipping hot chocolate and remote-controlling their rig from a laptop. As you can imagine, this essentially involves a server running on a computer hooked up to the radio, which is connected via the internet to a client running on the laptop. [Olivier/ F4HTB] saw a way to improve the process by eliminating the client software and controlling the rig from a web browser.

[Oliver]’s software, aptly named Universal HamRadio Remote, runs a web server that hosts an HTML5 dashboard for controlling the radio. It also pipes audio back and forth (radio control wouldn’t be very useful if you couldn’t talk!), and can be run on a Raspberry Pi. Not only does this make setup easier, as there is no need to configure the client machine, but it also makes the radio accessible from nearly any modern device.

We’ve seen a similar (albeit expensive and closed-source) solution, the MFJ-1234, before, but it’s always refreshing to see the open-source community tackle a problem and make it their own. We can’t wait to see where the project goes next!

It Came From Outer Space: Listening To The Deep Space Network

October 17, 2020 by Adam Zeloof 26 Comments

Ham radio operators love to push the boundaries of their equipment. A new ham may start out by making a local contact three miles away on the 2m band, then talk to somebody a few hundred miles away on 20m. Before long, they may find themselves chatting to fellow operators 12,000 miles away on 160m. Some of the adventurous return to 2m and try to carry out long-distance conversations by bouncing signals off of the Moon, waiting for the signal to travel 480,000 miles before returning to Earth. And then some take it several steps further when they listen to signals from spacecraft 9.4 million miles away.

That’s exactly what [David Prutchi] set out to do when he started building a system to listen to the Deep Space Network (DSN) last year. The DSN is NASA’s worldwide antenna system, designed to relay signals to and from spacecraft that have strayed far from home. The system communicates with tons of inanimate explorers Earth has sent out over the years, including Voyager 1 & 2, Juno, and the Mars Reconnaissance Orbiter. Because the craft are transmitting weak signals over a great distance (Voyager 1 is 14 billion miles away!), the earth-based antennas need to be big. Real big. Each of the DSN’s three international facilities houses several massive dishes designed to capture these whispers from beyond the atmosphere — and yet, [David] was able to receive signals in his back yard.

Sporting a stunning X-band antenna array, a whole bunch of feedlines, and some tracking software, he’s managed to eavesdrop on a handful of spacecraft phoning home via the DSN. He heard the first, Bepi-Colombo, in May 2020, and has only improved his system since then. Next up, he hopes to find Juno, and decode the signals he receives to actually look at the data that’s being sent back from space.

We’ve seen a small group of enthusiasts listen in on the DSN before, but [David]’s excellent documentation should provide a fantastic starting point for anybody else interested in doing some interstellar snooping.

Tracking Down Radio Frequency Noise Source, With Help From Mother Nature

September 25, 2020 by Dan Maloney 18 Comments

Amateur radio operators and shortwave listeners have a common enemy: QRM, which is ham-speak for radio frequency interference caused by man-made sources. Indiscriminate, often broadband in nature, and annoying as hell, QRM spews forth from all kinds of sources, and can be difficult to locate and fix.

But [Emilio Ruiz], an operator from Mexico, got a little help from Mother Nature recently in his quest to lower his noise floor. Having suffered from a really annoying blast of RFI across wide swaths of the radio spectrum for months, a summer thunderstorm delivered a blessing in disguise: a power outage. Hooking his rig up to a battery — all good operators are ready to switch to battery power at a moment’s notice — he was greeted by blessed relief from all that noise. Whatever had caused the problem was obviously now offline.

Rather than waste the quiet time on searching down the culprit, [Emilio] worked the bands until the power returned, and with it the noise. He killed the main breaker in the house and found that the noise abated, leading him on a search of the premises with a portable shortwave receiver. The culprit? Unsurprisingly, it was a cheap laptop power supply. [Emilio] found that the switch-mode brick was spewing RFI over a 200-meter radius; a dissection revealed that the “ferrite beads” intended to suppress RFI emissions were in fact just molded plastic fakes, and that the cord they supposedly protected was completely unshielded.

We applaud [Emilio]’s sleuthing for the inspiration it gives to hunt down our own noise-floor raising sources. It kind of reminds us of a similar effort by [Josh (KI6NAZ)] a while back.

Auxiliary Display Makes Ham Radio Field Operations Easier

August 29, 2020 by Dan Maloney 14 Comments

As popular as the venerable Yaesu FT-817 transceiver might be with amateur radio operators, it’s not without its flaws, particularly in the user interface department. [Andy (G7UHN)] is painfully familiar with these flaws, so he designed this auxiliary display and control panel for the FT-817 to make operating it a little easier.

There are a ton of ways to enjoy ham radio, but one of the more popular ways is to bust out of the shack and operate in the great outdoors. From the seashore to mountain peaks, hams love giving their rigs some fresh air and sunshine. The battery-powered, multimode, all-band FT-817 is great for these jaunts, but to fit as much radio into a small package as they did, Yaesu engineers had to compromise on the controls. Rather than bristling with buttons, many of the most-used features of the radio are buried within menus that require multiple clicks and twists to access.

[Andy]’s solution is a PCB bearing an Arduino Nano, an LCD screen, and a whole bunch of actual buttons. The board sits on top of the case and talks to the radio over a 8-pin mini-DIN cable using both documented and undocumented CAT, or Computer Aided Transceiver commands. The LCD displays the current status of various features and the buttons provide easy access to changing them, essentially by sending keystrokes to the radio.

Hats off to [Andy] for tackling this project. The only other FT-817 hack we’ve seen before was useful but far simpler, and didn’t require KiCad, which [Andy] had to teach himself for this one.

Mobile Transmitter Gets Internal GPS And Bluetooth

August 23, 2020 by Tom Nardi 4 Comments

While [Selim Olcer] was relatively happy with his Kenwood TM-D710a radio, he didn’t like the fact that it needed a bulky external GPS “backpack” for APRS location data. So he decided to crack open the head unit and see if he couldn’t integrate his own GPS hardware (machine translation). Not only did he succeed, but he even threw in Bluetooth compatibility for good measure.

With the repair manual circuit diagrams in hand, it was no problem to find the GPS RX and TX lines that were being broken out to the external connector. Unfortunately, the radio’s electronics are all 5 volts and the GPS module [Selim] wanted to use was only 3.3 V. So he came up with a small PCB that included not only the voltage regulator to power the GPS module, but also some voltage-dividers to level shift those signals.

Since the Kenwood TM-D710a was already designed to accept a GPS upgrade module, he just needed to change some configuration options in the radio’s menus for it to see the new hardware. Technically the project was done at this point, but since there was still room in the case and he had a GPS module spitting out NMEA sentences, [Selim] tacked on a common Bluetooth serial module so he could see the position information on his smartphone. With an application like APRSdroid, he now has a nice moving map display using the position pulled from the radio’s GPS.

With this modification done it looks like the head unit is ready to go, but that’s only the beginning for a mobile rig. Now we want to see how he integrates the whole thing into the car.

A Hybrid Helical Antenna For The Es’hail-2 Geosynchronous Repeater

August 4, 2020 by Dan Maloney 14 Comments

Amateur radio operators like to say that working a contact in space can be done with a simple handheld transceiver and a homemade antenna. And while that’s true, it’s true only for low Earth orbit satellites such as the ISS. If you want to reach a satellite in geosynchronous orbit it’ll take a little more effort, and this dual-feed helical “ice cream cone” antenna could really help.

Until recently, the dream of an amateur radio repeater in geosynchronous orbit remained out of reach, but that changed with the launch of the Qatari satellite Es’hail-2 last year. Since then, hams from Brazil to Thailand have been using the repeater, and UK-based [Tech Minds] has been in the thick of the action. The antenna he presents is a hybrid design, needed because of the 2.4-GHz band uplink and 10-GHz downlink on the satellite, also known as QO-100. Both require a largish dish antenna, with the downlink requiring a low-noise block downconverter (LNB) and feed horn. The uplink side of [Tech Minds]’ antenna is a helical design, with three-and-a-half turns of heavy copper wire and a tuning section of copper strapping that attaches directly to an N-type connector. The helix is just the right size for the feed horn of an LNB for the downlink side, nestled in a hole in the helical antenna’s aluminum reflector disc. There are 3D-printed parts to support everything, plus a cone-shaped radome to keep it all safe from the elements.

It looks like a great design, but sadly, North American and East Asian hams can only dream about building one, since QO-100 is below the horizon for us. We’re jealous, but we’re still glad the repeater is up there. Check out this article for more on how Es’hail-2 got the first geosynchronous ham repeater.

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