The Minima Is An All-Band HF Transceiver For Under $100

If you have ever browsed an amateur radio magazine you could be forgiven for receiving the impression that it is a pursuit exclusively for the wealthy. Wall-to-wall adverts for very large and shiny transceivers with hefty price tags abound, and every photograph of someone’s shack seems to sport a stack of them.

Of course, this is only part of the story. Amateur radio is and always has been an astonishingly diverse interest, and away from the world of shiny adverts you’ll find a lot of much more interesting devices. A lot of radio amateurs still design and build their own equipment, and the world of homebrew radio is forever producing new ideas.

One such project came to our attention recently, the Minima, an all-band HF SSB transceiver. It’s an interesting device for several reasons, it uses readily available components, it’s an impressively simple design, and it should cost under $100 to build. This might sound a little far-fetched, were it not from the bench of [Ashhar Farhan, VU2ESE], whose similarly minimalist BITX single band SSB transceiver set a new standard for accessible SSB construction a few years ago.

The circuit shares some similarities with the tried-and-tested BITX, using bi-directional amplifier building blocks. The mixers are now FETs rather than diodes, the intermediate frequency has moved from 9MHz to 20MHz, and the local oscillator is now an Arduino-controlled clock generator. The whole thing is designed to be built dead-bug-style if necessary, and two prototypes have been built. We’d expect this design to follow a similar evolution to the BITX, with the global community of radio amateurs contributing performance modifications, and no doubt with some kit suppliers producing PCBs and kits. We think this can only be a good thing, and look forward to covering some of the results.

We’ve featured [Ashhar]’s work here at Hackaday before, when we covered a BITX build. if you’re left wondering what this amateur radio business is all about, we suggest you have a read of [Bill Meara]’s guest post on the subject.

Thanks [Seebach] for the tip.

Two Guys, a Hotel Room and a Radio Fire

Can you build a HF SSB radio transciever in one weekend, while on the road, at parts from a swap meet? I can, but apparently not without setting something on fire.

Of course the swap meet I’m referring to is Hamvention, and Hamvention 2016 is coming up fast. In a previous trip to Hamvention, Scott Pastor (KC8KBK) and I challenged ourselves to restore tube radio gear in a dodgy Dayton-area hotel room where we repaired a WW2 era BC-224 and a Halicrafters receiver, scrounging parts from the Hamfest.

Our 2014 adventures were so much fun that it drove us to create our own hacking challenge in 2015 to cobble together a <$100 HF SSB transceiver (made in the USA for extra budget pressure), an ad-hoc antenna system, put this on the air, and make an out-of-state contact before the end of Hamvention using only parts and gear found at Hamvention. There’s no time to study manuals, antennas, EM theory, or vacuum tube circuitry.  All you have are your whits, some basic tools, and all the Waffle House you can eat.  But you have one thing on your side, the world’s largest collection of surplus electronics and radio junk in one place at one time.  Can it be done?

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Can you hear SamSat-218D?

Students of the Samara State Aerospace University are having trouble getting a signal from their satellite, SamSat-218D. They are now reaching out to the radio amateur community, inviting everybody with sufficiently sensitive UHF VHF band (144 MHz) equipment to help by listening to SamSat-218D. The satellite was entirely built by students and went into space on board of a Soyuz-2 rocket on April 26, 2016. This is their call (translated by Google):

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Listen to Meteors Live

When the big annual meteor showers come around, you can often find us driving up to a mountaintop to escape light pollution and watching the skies for a while. But what to do when it’s cloudy? Or when you’re just too lazy to leave your computer monitor? One solution is to listen to meteors online! (Yeah, it’s not the same.)

Meteors leave a trail of ionized gas in their wake. That’s what you see when you’re watching the “shooting stars”. Besides glowing, this gas also reflects radio waves, so you could in principle listen for reflections of terrestrial broadcasts that bounce off of the meteors’ tails. This is the basis of the meteor burst communication mode.

[Ciprian Sufitchi, N2YO] set up his system using nothing more than a cheap RTL-SDR dongle and a Yagi antenna, which he describes in his writeup (PDF) on meteor echoes. The trick is to find a strong signal broadcast from the earth that’s in the 40-70 MHz region where the atmosphere is most transparent so that you get a good signal.

This used to be easy, because analog TV stations would put out hundreds of kilowatts in these bands. Now, with the transition to digital TV, things are a lot quieter. But there are still a few hold-outs. If you’re in the eastern half of the USA, for instance, there’s a transmitter in Ontario, Canada that’s still broadcasting analog on channel 2. Simply point your antenna at Ontario, aim it up into the ionosphere, and you’re all set.

We’re interested in anyone in Europe knows of similar powerful emitters in these bands.

As you’d expect, we’ve covered meteor burst before, but the ease of installation provided by the SDR + Yagi solution is ridiculous. And speaking of ridiculous, how about communicating by bouncing signals off of passing airplanes? What will those ham radio folks think of next?

How Low Can You Go? The World of QRP Operation

Newly minted hams like me generally find themselves asking, “What now?” after getting their tickets. Amateur radio has a lot of different sub-disciplines, ranging from volunteering for public service gigs to contesting, the closest thing the hobby has to a full-contact sport. But as I explore my options in the world of ham radio, I keep coming back to the one discipline that seems like the purest technical expression of the art and science of radio communication – low-power operation, or what’s known to hams as QRP. With QRP you can literally talk with someone across the planet on less power than it takes to run a night-light using a radio you built in an Altoids tin. Now that’s a challenge I can sink my teeth into.

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Sage Advice for the New Ham

If you’re on the edge about getting your amateur radio license, just go do it and worry about the details later. But once you’ve done that, you’re going to need to know a little bit about the established culture and practices of the modern ham — the details.

Toward that end, [McSteve] has written up a (so far) two-part introductory series about ham radio. His first article is fairly general, and lays out many of the traditional applications of ham radio: chatting with other humans using the old-fashioned analog modes. You know, radio stuff.

The second article focuses more on using repeaters. Repeaters can be a confusing topic for new radio operators: there are two frequencies — one for transmitting and one for receiving — and funny control tones (CTCSS) etc. This article is particularly useful for the new ham, because you’re likely to have a relatively low powered radio that would gain the most from using a repeater, and because the technology and traditions of repeater usage are a bit arcane.

So if you’re thinking about getting your license, do it already. And then read through these two pages and you’re good to go. We can’t wait to see what [McSteve] writes up next.

The New Heathkit Strikes Again

Alright, this is getting embarrassing.

The rebooted Heathkit has added another kit to its offerings. This time it’s an inexplicably simple and exorbitantly priced antenna for the 2-meter band. It joins their equally bizarre and pricey AM radio kit in the new product lineup, and frankly we’re just baffled by the whole affair.

About the most charitable thing you can say about their “Pipetenna” is that it’ll probably work really well. Heathkit throws some impedance and SWR charts on the website, and the numbers look pretty good. Although Heathkit doesn’t divulge the design within the “waterproof – yes, waterproof!” housing, at 6 dBi gain and only five feet long, we’re going to guess this is basically a Slim Jim antenna stuffed in a housing made of Schedule 40 PVC tubing. About the only “high-end” component we can see is the N-type coax connector, but that just means most hams will need and adapter for their more standard PL-259 terminated coax.

Regardless of design, it’s hard to imagine how Heathkit could stuff enough technology into this antenna to justify the $149 price. Hams have been building antennas like these forever from bits and pieces of wire lying around. Even if you bought all new components, including the PVC pipe and fittings, you’d be hard pressed to put $50 into a homebrew version that’ll likely perform just as well.

The icing on this questionable cake, though, is the sales copy on the web page. The “wall of text” formatting, the overuse of superlatives, and the cutesy asides and quips remind us of the old DAK Industries ads that hawked cheap import electronics as the latest and greatest must-have device. There’s just something unseemly going on here, and it doesn’t befit a brand with the reputation of Heathkit.

When we reviewed Heathkit’s AM radio kit launch back in December, we questioned where the company would go next. It looks like we might have an answer now, and it appears to be “nowhere good.”