Sorry US; Europeans Listen To Space With GRAVES

August 27, 2017 by Al Williams 18 Comments

In Europe, the GRAVES radar station beams a signal on 143.050 MHz almost straight up to detect and track satellites and space junk. That means you will generally not hear any signal from the station. However, [DK8OK] shows how you can–if you are in Europe–listen for reflections from the powerful radar. The reflections can come from airplanes, meteors, or spacecraft. You can see a video from [way1888] showing the result of the recent Perseid meteor shower.

Using a software-defined radio receiver, [DK8OK] tunes slightly off frequency and waits for reflections to appear in the waterfall. In addition to observing the signal, it is possible to process the audio to create more details.

Why is there a giant vertical radar transmitter in the middle of France? The transmitter uses a phased array to send a signal over a 45-degree swath of the sky at a time. It makes six total steps every 19.2 seconds. A receiver several hundred miles away listens for reflections.

Even the moon reflects the signal when it is in the radar’s path. If you are interested in a moon bounce, you may be able to build a station to hear the reflections without being in Europe.

Of course, if you can transmit yourself, you might want to bounce your own signal off airplanes. If you want to do it old school, you could emulate [Zoltán Bay].

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Sniff Your Local LoRa Packets

August 22, 2017 by Jenny List 15 Comments

As the LoRa low-bandwidth networking technology in license-free spectrum has gained traction on the wave of IoT frenzy, LoRa networks have started to appear in all sorts of unexpected places. Sometimes they are open networks such as The Things Network, other times they are commercially available networks, and then, of course, there are entirely private LoRa installations.

If you are interested in using LoRa on a particular site, it’s an interesting exercise to find out what LoRa traffic already exists, and to that end [Joe Broxson] has put together a useful little device. Hardware wise it’s an Adafruit Cortex M0 Feather with onboard LoRa module, paired with a TFT FeatherWing for display, and software wise it scans a set of available frequencies and posts any packets it finds to the scrolling display. It also has the neat feature of logging packets in detail to an SD card for later analysis. The whole is enclosed in a 3D printed case from an Adafruit design and makes for a very attractive self-contained unit.

We’ve featured quite a few LoRa projects here, including this one with a Raspberry Pi Compute module in a remote display. Of more relevance in a LoRa testing sense though is this look at LoRa range testing.

ESP8266 Based Internet Radio Receiver Is Packed With Features

August 22, 2017 by Sean Boyce 36 Comments

Have a beautiful antique radio that’s beyond repair? This ESP8266 based Internet radio by [Edzelf] would be an excellent starting point to get it running again, as an alternative to a Raspberry-Pi based design. The basic premise is straightforward: an ESP8266 handles the connection to an Internet radio station of your choice, and a VS1053 codec module decodes the stream to produce an audio signal (which will require some form of amplification afterwards).

Besides the excellent documentation (PDF warning), where this firmware really shines is the sheer number of features that have been added. It includes a web interface that allows you to select an arbitrary station as well as cycle through presets, adjust volume, bass, and treble.

If you prefer physical controls, it supports buttons and dials. If you’re in the mood for something more Internet of Things, it can be controlled by the MQTT protocol as well. It even supports a color TFT screen by default, although this reduces the number of pins that can be used for button input.

The firmware also supports playing arbitrary .mp3 files hosted on a server. Given the low parts count and the wealth of options for controlling the device, we could see this device making its way into doorbells, practical jokes, and small museum exhibits.

To see it in action, check out the video below:

[Thanks JeeCee]

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Don’t Miss Watching This Solar Eclipse High Altitude Balloon Online

August 20, 2017 by Donald Papp 8 Comments

[Dan Julio] let us know about an exciting project that he and his team are working on at the Solid State Depot Makerspace in Boulder: the Solar Eclipse High Altitude Balloon. Weighing in at 1 kg and bristling with a variety of cameras, the balloon aims to catch whatever images are able to be had during the solar eclipse. The balloon’s position should be trackable on the web during its flight, and some downloaded images should be available as well. Links for all of that are available from the project’s page.

High altitude balloons are getting more common as a platform for gathering data and doing experiments; an embedded data recorder for balloons was even an entry for the 2016 Hackaday Prize.

If all goes well and the balloon is able to be recovered, better images and video will follow. If not, then at least a post-mortem of what the team thinks went wrong will be posted. Launch time in Wyoming is approximately 10:40 am ~~Mountain Time (UTC -07:00)~~ Mountain Daylight Time (UTC -06:00) on Aug 21 2017, so set your alarm!

Crowdsourcing The Study Of An Eclipse’s Effect On Radio Propagation

August 17, 2017 by Jenny List 23 Comments

If you are an American, you’ll probably now find yourself in one of three camps. People who are going to see the upcoming solar eclipse that will traverse your continent, people who aren’t going to see the eclipse, and people who wish everyone would just stop going on incessantly about the damn eclipse.

Whichever of those groups you are in though, there is an interesting project that you can be a part of, an effort from the University of Massachusetts Boston to crowdsource scientific observation of the effect a solar eclipse will have on the upper atmosphere, and in particular upon the propagation of low-frequency radio waves. To do this they have been encouraging participants to build their own simple receiver and antenna, and make a series of recordings of the WWVB time signal station before, during, and after the eclipse traverse.

This is an interesting and unusual take upon participation in the eclipse, and has the potential to advance the understanding of atmospheric science. It would be fascinating to also look at the effect of the eclipse on WSPR contacts, though obviously those occur in amateur bands at higher frequencies.

If you are an EclipseMob participant, we’d love to hear from you in the comments. Does your receiver perform well?

Thanks [Douglas] for the tip.

ColibriNANO USB SDR Receiver Reviewed

August 8, 2017 by Al Williams 26 Comments

At first glance, the ColibriNANO SDR looks like another cheap SDR dongle. But after watching [Mile Kokotov’s] review (see video below), you can see that it was built specifically for software defined radio service. When [Mile] takes the case off, you notice the heavy metal body which you don’t see on the typical cheap dongle. Of course, a low-end RTL-SDR is around $20. The ColibriNANO costs about $300–so you’d hope you get what you pay for.

The frequency range is nominally 10 kHz to 55 MHz, although if you use external filters and preamps you can get to 500 MHz. In addition to a 14-bit 122.88 megasample per second A/D converter, the device sports an Altera MAX10 FPGA.

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