Sunday, December 30, 2012

Radio Interferometer: status update

As you probably do not know, I'm currently trying to build a semi-digital radio interferometer at 408MHz, for astronomy. I played around a bit with patch antennas, and did some very basic "interferometry" tests with them.
Some extremely bad tinfoil patch antennas being used for "interferometry"

Saturday, December 15, 2012

usbtmc on newer kernels

Just a quick note, if you want to use usbtmc (tmc is a protocol to control measurement devices remotely), the version in the linux kernel doesn't really seem to work. There's one from Agilent which works fine, the installation procedure is described here. However it doesn't compile on newer kernels unless you do these changes:

After that, it works just fine: 
# cat /dev/usbtmc0
Minor Number    Manufacturer    Product Serial Number
001     Rigol Technologies      DSA815  DSA8AXXXXXXXX

Here's a very simple and very bad python script which can be used to connect to a device, send commands and view the results (the output file stuff is device specific so don't use it):

At this point, a big WTF towards the blogger editor: It's impossible to insert the left and right angle chars correctly if they are arranged like for C includes. If you paste them in the WYSIWYG mode, they get interpreted as HTML tag (!) and if you input them in HTML mode, they're displayed as... I can't even write it down, since the WYSIWYG mode obviously translates ampersand-sequences to characters... you know, those &; sequences. Come on, that can't be so difficult to get right.