Thursday, January 14, 2010

Why SDR doesn't excite me

In his latest blog post Dave Richards, AA7EE writes: "I have an interest in SDR. At this stage in the game, I would imagine that almost anyone with an interest in radio, whether amateur radio or any other kind of serious listening, would find SDR very compelling." I'm afraid I don't. In fact I find the idea of SDR depressing, even repelling. And that isn't just because I prefer the look and feel of a real radio with buttons and knobs to a computer screen.

I say this even though I am a programmer of sorts. I have tried to learn how SDR works with the idea that if I could write my own SDR software it might become an aspect of the hobby I could get interested in. But I can't. The math is totally beyond me and I just can't understand how it works at all. The majority of radio amateurs without any knowledge of programming don't have a chance. Which makes the limit of most people's technical challenge in an SDR future that of getting somebody else's SDR software to work. And after a lifetime working with computers frankly I don't find faffing about with PCs very much fun.

A basic understanding of electronics is one of the prerequisites of getting a ham radio license. Although most of us could not design an Elecraft K3 and many of us choose never to design or even build any part of our station, most of us can understand how radio circuits work and quite a few of us can build simple circuits from a schematic. Some of us can even design circuits from scratch - a lot more of us I'd wager than could write their own SDR software.

The reason I don't like SDR is that it reduces the majority of us to the role of appliance operators. That may be fine for those who are happy being appliance operators and just want the best technical solution for working weak DX or amassing the most contest points. But for the tinkerers and builders SDR doesn't leave a lot to experiment with, because most of the interesting stuff happens in software, inside the computer, where we don't have the tools or the knowledge to tinker with it. If you are using a SoftRock or a top of the line Flex you will be looking at the same software user interface. And I don't find that a very enthralling prospect.


Ed N4EMG said...

Hi Julian,

I'll admit to be very intrigued initially about SDR. And while it still holds an interest for me, I have never seen one in action, only via video postings. It does certainly look impressive and it seems that the handful of manufacturers continue to make nice strides.

The debate about real knobs and buttons will continue to rage. I expect that it would be unusual at first, but probably something that one could warm up to eventually. Some might find changing to a computer only display to be no challenge whatsoever.

You raise accurate and valid points, the normal ham could never work on this, but I guess that's true for most of the new radios on the market today already. Indeed, I believe that's what makes the Elecraft appeal extra special. You don't design it, but you do build it, although that's certainly less true with the K3. You assemble it. You have an extra stake in it, let's say.

Oddly, I have yet to read many negatives about SDR and I'm sure there must be some. It is almost like the Elecraft following, you don't dare say anything negative. And while I'm a huge fan of Elecraft, owning a K2, let's face it, it isn't close to being perfect. But the lack of frankness concerns me. Tell me the bad along with the good, then I'll put more stock in what they're saying.

73 Ed

Unknown said...

On the Elecraft reflector you'll read a few negatives. Amateur SDRs don't have the dynamic range of the top analog radios because they don't work at enough bits (I believe it is possible but the chips are expensive.) There are also concerns about stability, because it runs on a computer. There is a latency issue due to the fact that software has to buffer the data before processing it, which bothers contesting types who fret over every lost millisecond. And I don't think an SDR has yet been made that does QSK accepable to the CW aficionados. The common saying is that "when the top contesters and Dxpeditions use SDR, then you can take it seriously."

I agree that most hams never work on their store-bought radios, which is why I think SDR will eventually become commonplace. But I do worry about where that leaves the hobby. The fact that I can look at the K2 schematic and understand exactly what happens and at least contemplate how it could be improved is one of the few things that differentiates talking to someone on the radio and using the phone or the internet. And I don't want to lose that.