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Comment Re:Computer Not Required (Score 1) 177

Yes, I just picked up a SDRPlay 2 last weekend.

The main differences between it and the Funcube dongle are the same: the SDRPlay can sample at much higher rates, but only at 12 bits/sample, while the Funcube dongle samples at 192 kHz with 16 bits. The Funcube dongle therefore appears better suited to narrower modes, especially on HF and VHF where there may be strong interferers on nearby frequencies. The SDRPlay can do broadband modes too wide for the Funcube, such as HD Radio, ADS-B and digital TV, though many of those can also be done even more cheaply with 8-bit RTL-SDR dongles. The SDRPlay can also produce wideband waterfall displays.

Comment Re:Computer Not Required (Score 1) 177

I/Q interfaces are vulnerable to ground loops only if the I/Q interface is analog. Why should it be, when we have excellent digital interfaces designed specifically for stereo digital audio? There are now several inexpensive SDRs (price range $100-$200) with USB interfaces, e.g., the Funcube Dongle Pro+ and the SDRPlay (there's now a second version). There's also the ultra-cheap RTL-SDR, but its narrow 8-bit A/D limits its use to VHF or UHF signals without strong adjacent channel interference. It's ideal for ADS-B (with a filter!) but I wouldn't recommend it for HF.

I've done most of my work so far with the Funcube dongle, which samples at 192 kHz and 16 bits/channel, feeding a USB interface. It looks just like a standard audio A/D to the OS, because that's what it is. The I&Q signals are produced at baseband so yes there are DC offsets and small gain and phase errors, but I found them easy to remove in software. Some phase noise is sometimes audible within a few hundred hertz of DC, but is easily swamped by typical input noise and gain settings.

Overall, this thing makes an excellent but inexpensive general coverage receiver. I sure wish I had something like this when I was a young ham without much money.

Comment Re: Ham Radio? (Score 1) 177

Probably the ultimate in QRP right now is WSPR (Weak Signal Propagation Reporter). This is a specially-designed very low speed (~1 bps) digital modulation and coding format designed for use as a propagation beacon, especially on the HF ("shortwave") bands. But it has recently been adapted for tracking ultra light weight (12.5 gram!) high altitude balloon payloads. One such payload, WB8ELK-2, has completed three complete trips around the world in the past month and is now on its fourth:!m...

The tracker payload is powered directly by a pair of small thin-film solar panels. The weight budget is so extremely tight that there is no battery, so it transmits only during the day.

Comment Re: Ham Radio? (Score 1) 177

Well, not to toot my own horn too loudly, but in the mid 1980s I wrote a TCP/IP implementation. I intended it for ham radio use on low end PCs, as the only existing general purpose implementations were on commercial minicomputers far beyond a ham budget. (I actually began it on a dare by Terry Fox, WB4JFI, who insisted it was too complex to implement on anything a ham could afford.)

Before I knew it, my software was being widely used outside ham radio for dialup access to the Internet. Universities and companies set up banks of modems and PCs to give their students and employees access to their existing connections. Pretty soon commercial companies sprang up to do the same for the public, again using my software; I think we now call them "Internet Service Providers".

Meanwhile, the OSI world was continuing to produce large piles of paper, but no inexpensive (or free), usable software.

In the early 1990s, I went to Qualcomm where I ported my code onto their phones so it could be used to provide wireless Internet services.

Sure, my software is long obsolete now. When people still ask about it, I tell them to go look at Linux. But it once played a role that went well beyond ham radio, even though that's all I had originally meant it for. Perhaps this was an example of a butterfly flapping its wings; I don't know.

Comment Re:Good reason to avoid proprietary ham software (Score 2) 177

I was just trying to say exactly that, but Slashdot lost my edited comment when I changed an option. Argh.

I never said all hams should build their own radios. But all hams should be able to learn how their radios work, if they are so inclined, and to modify and experiment with them. That's what the hobby is supposed to be about. It's exactly the same philosophy behind the open source software movement, only we hams had it first.

Most ham manufacturers still make hardware schematics available for their equipment, but microcontroller firmware has always been a sore point, especially with more and more functionality moving into DSP (as it should).

Yes, I am working on open source DSP software for the Raspberry Pi (or any other Linux platform) and inexpensive software-defined radio (SDR) front ends like the Funcube Dongle and the SDRPlay. (All three products come from the UK. Not sure what that means, but I'm glad they're making them.)

But my biggest beef is with ham digital voice. There are not one, not two but THREE mutually incompatible digital voice "standards" in common use on the VHF/UHF bands here in soCal: Fusion (Yaesu), D-Star (Icom) and DMR (Motorola). All three modulation and coding designs are dated and inefficient, with disappointing performance. Worse, they all use the same proprietary digital voice codec (AMBE) that's patented out the wazoo. It must be purchased on a custom DSP when it could easily be implemented in software on the same DSPs that do everything else in the radio. This is despite the ready availability of a superior, un-encumbered ham-developed algorithm called CODEC2 (by Dave Rowe, VK5DGR). The manufacturers simply ignore it, and few of us hams are in the position to mass-market small hand-held radios.

Comment Re:Ham Radio? (Score 5, Informative) 177

Yes, ham radio is still very much a "thing". But to me, the one "thing" it never has been is the purchasing of closed, proprietary software that can be turned off at whim by the developer. To me, ham radio has always been a unique hands-on opportunity to learn what's "behind the knobs" of a piece of communications hardware (or now, software). Even if you don't build (or write) your own stuff, even if you're primarily interested in using it to talk to others, it still gives you (or should give you) the opportunity to learn how it all works, to make technology just a little less mysterious and intimidating. Ham radio still provides a creative outlet for hundreds of thousands of people. It helps STEM students learn about electronics, math, physics, or just about any other field of science and engineering even remotely associated with radio communications, such as computers and networking, satellites and remote sensing. When I got into it in high school nearly 50 years ago, it confirmed for me that I wanted to become an electrical engineer, a decision I have never regretted. Even many who decide that a STEM career isn't for them are hams simply because it's an enjoyable hobby.

Comment Good reason to avoid proprietary ham software (Score 4, Insightful) 177

I had not heard this story, but that might be because I don't personally use Ham Radio Deluxe or any other proprietary ham software, certainly nothing that can be controlled in this way. Other hams are free to use whatever they want, but I personally consider proprietary software to be fundamentally incompatible with the nature and purpose of ham radio.

Comment Re:Public-key cryptography is the death of freedom (Score 2) 55

I don't like locked-down computers any more than you do. I hate ransomware even more; it's the single most despicable use of public key cryptography there is. But consider that without public key cryptography Apple wouldn't even be in a position to stop the FBI from hacking the iPhone. Individuals wouldn't even have the option to secure their personal communications, at least not in practice. (Yes, I know all about one-time pads. That's why I said "in practice"). Nor would we have the Internet, or at least anything like the one we have now. And without the Internet, computers of all kinds (secure or non-secure boot) wouldn't be nearly as capable and available as they are now because the volume and demand would be vastly less.

Comment Can't think of more deserving recipients (Score 3, Interesting) 55

I really can't think of more deserving recipients. I've never met Hellman, but I've met Diffie a few times, including when we testified to the Senate Commerce Committee during the 1990s Crypto Wars. He's a national asset whenever the NSA and FBI get a little too far out of line. Which is most of the time.

Comment CO2-sugar (Score 2) 158

Well, I've recently developed a machine to convert atmospheric CO2 into various simple organic molecules known as "sugars", which have the significant advantage over methanol of being relatively nontoxic. My design has been successfully tested for some time and it only requires sunlight, water and a few miscellaneous other inexpensive materials. And best of all, my machine is self-replicating!

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If I'd known computer science was going to be like this, I'd never have given up being a rock 'n' roll star. -- G. Hirst