weak signal

4 Articles

A Super-Simple Standalone WSPR Beacon

June 14, 2024 by 26 Comments

We’ve said it before and we’ll say it again: being able to build your own radios is the best thing about being an amateur radio operator. Especially low-power transmitters; there’s just something about having the know-how to put something on the air that’ll reach across the planet on a power budget measured in milliwatts.

This standalone WSPR beacon is a perfect example. If you haven’t been following along, WSPR stands for “weak-signal propagation reporter,” and it’s a digital mode geared for exploring propagation that uses special DSP algorithms to decode signals that are far, far down into the weeds; signal-to-noise ratios of -28 dBm are possible with WSPR.

Because of the digital nature of WSPR encoding and the low-power nature of the mode, [IgrikXD] chose to build a standalone WSPR beacon around an ATMega328. The indispensable Si5351 programmable clock generator forms the RF oscillator, the output of which is amplified by a single JFET transistor. Because timing is everything in the WSPR protocol, the beacon also sports a GPS receiver, ensuring that signals are sent only and exactly on the even-numbered minutes. This is a nice touch and one that our similar but simpler WSPR beacon lacked.

This beacon had us beat on performance, too. [IgrikXD] managed to hit Texas and Colorado from the edge of the North Sea on several bands, which isn’t too shabby at all with a fraction of a watt.

Thanks to [STR-Alorman] for the tip.

[via r/amateurradio]

The $50 Ham: A Simple WSPR Beacon

April 15, 2021 by 27 Comments

I was having a chat recently with someone, and it surprised me that she had an amateur radio license. I suppose it shouldn’t have come as much of a surprise; after all, getting a ham radio license is a pretty common rite of passage in the life of a hardware hacker. I guess it surprised me because she’d never mentioned it in our past conversations, and as we talked about it, I learned why. “I got my license because I thought ham radio was about building radios, ” she said. “But it’s not.”

In a lot of ways, she is right about the state of ham radio. There was a time that building one’s own gear was as central to the hobby as getting on the air, and perhaps more so. Now, though, with radios as cheap as $30 and the whiz-bang gear that can make reaching out across the planet trivially easy, building your own radios has slipped down a few notches. But homebrewing is far from a dead art, and as we’ll see in this installment of “The $50 Ham”, a WSPR beacon for the HF bands is actually a fun and simple — and cheap — way for the homebrew-curious to get a taste of what it’s like to build your own transmitter.

Continue reading “The $50 Ham: A Simple WSPR Beacon” →

The $50 Ham: WSPR-ing Around The World

March 25, 2021 by 18 Comments

Everybody has a bucket list,  things to be accomplished before the day we eventually wake up on the wrong side of the grass. Many bucket-list items are far more aspirational than realistic; very few of us with “A trip to space” on our lists are going to live to see that fulfilled. And even the more realistic goals, like the trip to Antarctica that’s been on my list for ages, become less and less likely as your life circumstances change — my wife hates the cold.

Luckily, instead of going to Antarctica by myself — and really, what fun would that be? — I’ve recently been getting some of the satisfaction of world travel through amateur radio. The last installment of “The $50 Ham” highlighted weak-signal digital modes using WSJT-X; in that article, I mentioned a little about the Weak Signal Propagation Reporter, or WSPR. It’s that mode that let me test what’s possible with very low-power transmissions, and allowed me to virtually visit six continents including Antarctica and Sweden-by-way-of-Alaska.

Continue reading “The $50 Ham: WSPR-ing Around The World” →

The $50 Ham: Digital Modes With WSJT-X

February 10, 2021 by 33 Comments

As it is generally practiced, ham radio is a little like going to the grocery store and striking up a conversation with everyone you bump into as you ply the aisles. Except that the grocery store is the size of the planet, and everyone brings their own shopping cart, some of which are highly modified and really expensive. And pretty much every conversation is about said carts, or about the grocery store itself.

With that admittedly iffy analogy in mind, if you’re not the kind of person who would normally strike up a conversation with someone while shopping, you might think that you’d be a poor fit for amateur radio. But just because that’s the way that most people exercise their ham radio privileges doesn’t mean it’s the only way. Exploring a few of the more popular ways to leverage the high-frequency (HF) bands and see what can be done on a limited budget, in terms of both cost of equipment as well as the amount of power used, is the focus of this installment of The $50 Ham. Welcome to the world of microphone-optional ham radio: weak-signal digital modes.

Continue reading “The $50 Ham: Digital Modes With WSJT-X” →