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ALSA Audio for the Raspberry Pi

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I ordered a Raspberry Pi about the time it was announced last year. At the time, it was necessary to order it from the UK. As a result of SNAFUs, I didn’t receive it till the end of last summer. By then, I was deep into work requirements that gave me little personal time. No time for ham radio, for sure.

Just a few days ago, I got past the point of loading Raspbian onto an SD card and getting the device to boot. Although I have a general interest in the Pi, and had already been exploring applications with a similar device, the “Guru Plug”, I now have a specific application for the Pi.

My first application is an audio/radio application that is running on several of my computers, and is starting to monopolize hardware that I’d rather be using in other ways. So my first definite Pi project is to get that audio project running on the Pi, so I can offload my other, more valuable systems, and return them to their original purposes. The application requires ALSA audio on Debian/Ubuntu, and not too much processing power. The Pi seemed a good fit. So, once I got it up and running, the question was: Does it support ALSA, and if so, does it support the Debian audio tools enough that my project will run on it? I don’t have the definitive answer yet, but it’s looking good.

Yes, the Pi supports ALSA audio. However, the support is NOT done in hardware per se (that is, not as in most modern laptops). It’s partial emulation, and partially the bcm2835 chip used in the Pi for HDMI output. This requires a kernel module that, in the case of the Pi on the “official” Raspbian distro, is loaded at boot time by default.

For more technical discussion of this subject, please see this page on the WA2IAC wiki.

Friday AM Fun Day

Status

I had a good wake-up this morning starting at around 6:15. I woke up early this morning, turned on the Boulder remote, and tuned to 3.875 just in time to hear the beginnings of AM activity. Lots of very fine signals!

I enjoyed a round-table with Steve N0BF, Rod W5CZ,OJ K0OJ, Jack K0HEH, Mark KA0SKK, Rob W0FT,Jerry KD0PD, Steve W7JSC.

OJ remarked he had worked some 10M AM’ers in New Hamster on 29.05, which sounded very encouraging! I’m still hoping for some QRP/DX activity like I enjoyed during the last solar maximum. KA0SKK’s 3 807’s modulated by two more 807 bottles sounded fine, and brought back memories of hacking around with a Johnson Mobile I rigged up with an outboard solid state modulator (it was borrowed from the K2TK club founded by W2AAF [SK]). W7JSC was making it in from somewhere in the field near Cheyenne, WY with a R7000 to 100′ of wire, weak but full copy.

Moving

Status

During July and into August, I’m going through personal changes… new work, and moving. Not very far. But as a ham, there’s always an extra-added dimension to moving.

Questions like: Where will I put my gear? Where will I store the gear I’m not using. Should I sell some stuff.

Even more important questions like: Where can I put an antenna? What kind/how big? Will I be able to run QRO? Or, in restricted situations like mine, can I put up an antenna at all?

The good news is that my new QTH is at ground level. I’ve been on the third floor, which presents ground challenges. But I’ve learned how to cope with those issues very effectively over the years. The new QTH is at ground level. That will change the challenge to one of getting the antenna(s) as high as possible. Looks like I’ll be able to put up my trap 15/20m dipole for sure, as well as a stealthily placed 2m/70cm beam that will be on a better path to the BARC repeaters (sure would like to work some ATV on Thurs evenings). There is also the opportunity to put up a stealth longwire, at least 300 feet. Possibly better. As for putting up something more resonant to get on 40M and 75/80M with, I can only try and experement! But clearly, the futures for putting up antennae in the new place are better.

Perhaps moving won’t seem so bad as a result.

And now, back to the boxes…

Welcome to the Blog

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73 All — I’ve been busy, and it looks like I’ll be getting busier. I don’t want that to get in the way of posting new information, so to make it easier on myself I set up this blog.

There are still lots of updates and new material for the website, and this blog will not replace those. What the blog will do is make it easier for me to make regular updates about my activities, my shack, my ham related interests, and so on.

As an additional benefit, blogs are naturally interactive. So please, feel free to comment. If you’d like to make this blog a place to make your own posts, that’s a possibility too – let me know.

If you’d like to set up a username so you can post or comment, great! Just include your callsign somewhere in your username so you don’t get deleted with the spammers!

Thanks and 73,

Gregg WA2IAC