Thursday, December 30, 2010
I found this awesome youtube video of a airborne SAR data set from all aspect angles. Apparently you can download this, the
on request from this page.
Sounds like a great opportunity to process some airborne SAR data.
Tuesday, December 21, 2010
If you like this blog then support my dad's flower shop. This shop has been in the family since 1893 and has supported many of my engineering endeavors and college tuition payments.
In this video my dad shows step-by-stop how to make a floral arrangement for your holiday party. You can get the greens by taking a walk in a local park, but consider getting the flowers from my dad's flower shop, he will deliver anywhere:
The 8552 IF section of my 10Mc-18Gc spectrum analyzer (HP141T with the 8555A plug-in and 8552 IF) stopped working recently during the fabrication of the MIT IAP course radar. While trouble shooting the problem i took these photos to show the insides.
The 141T/8552/8555A remains my favorite spectrum analyzer. Now that it is working again i hope to get a few more decades of use out of it.
Saturday, December 18, 2010
Thursday, December 16, 2010
Peter AI4PP/SV0XAW noticed my old-school looking homebrew 20m SSB transceiver on the solder smoke blog. After looking at the photos inside of the radio he suggested i should try cable lacing for my next project.
Cable lacing is a method of dressing a wiring harness before wire ties inside of a piece of equipment. If you open up an old military radio or piece of HP test gear from the 1950's you will see cable lacing. Creating radio equipment is an art form and cable lacing provides a nice finishing touch.
Thank you for the suggestion Peter, I plan to look into this for my next radio project.
(images from http://www.dairiki.org/hammond/cable-lacing-howto/).
Monday, December 13, 2010
I'm a big fan of National Semiconductor's Web Bench. Recently i have used it to design a 4th order active low-pass filter that worked well first time i tried it.
Similar results would occur if you were to scale designs from my favorite active filter book, Lancaster's Active Filter Cookbook.
Two resources to keep in mind next time you are required to use an active filter.
Thursday, December 9, 2010
I purchased a new (old) grid dip meter a local hamfest for $10, the Heathkit GD-1B. Built in the 1950's this grid dip meter still works great, no need to restore it and it came with a full set of coils.
I plan to use this for, among other things, finding the AL values of salvaged toroid cores.
Sunday, December 5, 2010
I have received many questions asking why I prefer the sound of tubes more than all of the solid state amplifiers i have heard to date. Fortunately, IEEE Spectrum has addressed this tube sound phenomenon and the industry of tube amplifier manufacturing in, 'The Cool Sound of Tubes.' One of the most interesting parts of this article is the comparison of several different solid state AF gain stages to triode and pentode equivalents. It was found that the triode produced the least harmonic distortion and provided greatest dynamic range of all. It is important to note that these test circuits did not use degenerative feedback which would certainly lower the harmonic distortion in all circuits, it would be interesting to perform this test.
Non the less, i think this is a fine article discussing the tube vs. transistor issue and it provides an overview of those who prefer to use tubes and have a the best reasons to do so.