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Posts tagged with 'ubuntu-hams'

Steve

Antenna modeling using nec2c on Ubuntu Linux

July 22, 2011

by Steve

Under amateur radio , ham , ham radio , hamradio , linux , open source , planetubuntu , ubuntu , ubuntu linux , ubuntu-hams | Comment

New Thing! Video!

I’ve been playing with antenna modeling, and decided to make a video series introducing this to other people who may be interested.

I’m new to this, but I think it came out pretty well. I only misspoke a couple of times, but it will probably only be noticed by the technical pedants (I count myself among these).

The first episode covers the basic user interface and some basic concepts. I already have plans to make more episodes, possibly with these topics:

Basic data input file format for xnec2c
Antenna tuning, resonance
Single band beam antennas, more elements for more directivity
The dB (Decibel) – as a unit AND a referenced quantity
SWR – what it is, why it matters, and when it doesn’t
How antenna height affects gain and impedance
How to model traps in xnec2c
Near field analysis – why do you need it and what does it mean?

I need to figure out where to place show notes for these, as there are a lot of good information sources about these topics on the internet already, and I need to reference those in each episode. I’ll get smoother at all that.

For the first episode, here’s how you can fetch the example files:

git clone git@github.com:sconklin/Antenna-Modeling.git

Here’s a link to my show page on blip.tv

And here’s the embedded episode:

Steve

Rescheduled: Ubuntu and Amateur (Ham) Radio for Ubuntu Open Week

May 5, 2011

by Steve

Under amateur radio , ham , ham radio , hamradio , linux , planetubuntu , ubuntu , ubuntu linux , ubuntu-hams | Comment

Note that this was rescheduled due to me being busy with disaster recovery. We can talk about that, too if anyone is interested.

–

Please join us on Friday, May 6th at 14:00 UTC for:

Ubuntu and Amateur (Ham) Radio for Ubuntu Open Week

Steve Conklin AI4QR, and Kamal Mostafa KA6MAL

Curious about what you can do with Amateur Radio and Ubuntu?
Curious about Amateur Radio in general?

Steve and Kamal will take questions and do their best to answer them.

—-

Amateur Radio is a hobby and a public service enjoyed by at least a million people around the world. Whether you are interested in transmitting and receiving radio signals around the world to meet new people, in being of service after disasters, or in the technical aspects, there is probably something for you.

Amateur Radio covers a huge number of interests, including local and long distance communications, emergency communications, satellite communications, digital networks, competitions, and electronics design.

Ubuntu offers many software applications related to Amateur Radio. We’ll discuss some of our favorite apps for use in the “ham shack”, and show how you can receive and decode digital conversations and telemetry with Ubuntu and any shortwave radio receiver (no Amateur Radio license required!).

We will be holding an open Question and Answer session:

When: Friday May 6th at 14:00 UTC

Where: In the #ubuntu-classroom and #ubuntu-classroom-chat channels on freenode IRC.

For more information about IRC:

Here’s a web client for IRC:

You don’t have to wait until the session to learn more about Ubuntu and Amateur Radio and meet other interested people. Check out our team information page or drop into #ubuntu-hams on freenode IRC.

73, DE AI4QR

Calibrating the softrock RX/TX Ensemble on Ubuntu

September 13, 2010

Under amateur radio , hamradio , sdr , softrock , ubuntu , ubuntu-hams

Continuing my exploration of SDR and the Softrock RX/TX Ensemble …

You can catch the beginning of those posts here.

The programmable oscillator on the softrock runs (in my case) at four times the desired mixer frequency. My unit is set to start up at 14.080 MHz, in the 20m band.

But - it would start up with the master oscillator running off frequency, which led to calibration being shifted by about 20 KHz on the band.

I’ve been using an application called usbsoftrock to access the firmware interface on the radio. Usbsoftrock is available packaged for Ubuntu as described here. I think that usbsoftrock is supposed to allow me to calibrate my radio so it will start on frequency every time. I grabbed the source for usbsoftrock, and read the README, and it looks like the proper steps are to run the calibrate command:

$ ./usbsoftrock -a calibrate
Version : 15.12 fXTALL = 114.440115

Then as I understand it, I can just set the crystal frequency in the radio eeprom like this:

$ ./usbsoftrock -a set xtall 114.440115
Version : 15.12

This just resulted in the exact same behavior. Actually, when I ran the calibrate command, the frequency would change to being much closer to where it should be, but it was still a bit off. As soon as I would cycle power, it would return to the original value.

I decided to experiment with writing different crystal frequencies to the eeprom, and had the following results, measuring after cycling power:

Set xtall | Output
——————-|——————
114.265 | 56.3253
114.2745 | 56.3207
114.275 | 56.3204
114.2758 | 56.3200 <——-
114.285 | 56.3155
114.440 | 56.2390

Since I want it to start at 14.080 MHz, the correct value is four times that or 56.3200 MHz. Incidentally, I’ve been measuring at top hairpin lead of R13 using a frequency counter.

Having written the correct value, the radio starts up on frequency every time. It’s very close to being dead on, I can tell by listening to WWV on 10 MHz.

I’m not sure why the procedure I thought I should use with usbsoftrock didn’t work. I may investigate that more later. I’ve asked on the yahoo softrock group, and there’s a lot of expertise there. If I get an answer I’ll post an update here. Otherwise, at least here’s a trial and error method for you.

Once I got the radio into a case and out of the rats-nest of cabling that I was using for testing, and disconnected the counter, the signal quality improved drastically. Here’s a screenshot covering the 20m band from about 14.050 to 14.095 MHz. You can see some CW at the left, a bunch of psk31 traffic around 14.070, and rtty around 14.085. It was amazing to see the phone portion of the band, there’s some sort of contest going on this weekend.

"At this point, since Ubuntu is beginning to look like a really viable alternative OS, the next big..."

July 27, 2010

Under hamradio , ubuntu , ubuntu-hams

“At this point, since Ubuntu is beginning to look like a really viable alternative OS, the next big issue is whether it will support the ham radio applications that we want to run. Fortunately, the answer to this question is — yes it will.”

- - Ubuntu Linux for Hams