Vic's Tech Blog: October 2013

Wednesday, October 30, 2013

My First Heathkit

In the winter of 1968, I was taking a French class in 9th grade and wanted to tune in to some foreign shortwave stations to listen to real French being spoken. I ordered the cheapest Heathkit shortwave receiver, the model GR-81, that they had for $24. I put it together and got it working and was amazed and dissapointed at the same time. I had never used a regenerative receiver before and discovered that they made lousy shortwave receivers for AM broadcast signals but made excellent ham band receivers. Suddenly, I could understand the single sideband phone signals on the ham bands and could hear CW (international morse code) as tones rather than thumps. I quickly taught myself the Morse code, got my ham license, forgot all about French and the rest is history. I owned a number of used Heathkit ham receivers and transmitters but only built three Heathkits in my life - the GR-81, an HW-8 portable CW transceiver and the IG-5218 audio generator. I actually still have and use the audio generator that I built in the early 80s.

Thursday, October 24, 2013

FORTRAN - 1954

In 1954, the first FORTRAN program was run on an IBM 704 mainframe. I remember those darn keypunch cards and Fortran from my engineering classes at the University of Washington in 1975. This photo is courtesy of Geeks Fun Blog.

Saturday, October 19, 2013

Navy LF Transmitters

How do you communicate directly with a sub under water? You use very low frequency RF 15-30 kHz and LOTS of power (1MW). I live 20 miles from one of these Navy transmitters (Jim Creek, WA) and had the pleasure to tour it once with a hamfest group in the 1980s. I worked in a TV station so was used to broadcast sized transmitters but was still in awe at antenna tuner coils that you could stand up inside of. They wouldn't let us take pictures since it was an active site but here are some links from around the web of virtual tours, pictures, etc:

Yosami Japan VLF station using mechanical generators

Jim Creek,WA virtual tour

Wednesday, October 16, 2013

Edison Electric Light

On October 15, 1878, Thomas Edison invented the electric light. To be more accurate, he perfected an incandescent light bulb that could last longer than 10 seconds. I disagree about it affecting the soundness of sleep....

Wednesday, October 9, 2013

Darth Vader Made from Tech

Workbenches For Electronics

my current workbench 2013

my workbench 2008-2011

the late Jim Williams' workbench

EDN slideshow of Bob Pease and Jim Williams

neatly organized workbench

functional and good layout

Sunday, October 6, 2013

Lightning on Demand

The Lightning on Demand (LOD) project is attempting to build a project with two 10 story Tesla coils separated by 260 feet to study lightning. Find more information at the Lightning Foundry website. To make a living, I have to work on practical devices to sell to consumers but this would be a sweet and crazy gig.

Saturday, October 5, 2013

Keys, Bugs and Paddles

When I first became a ham, I somehow acquired a J-38 hand key. This was a top of the line WWII surplus telegraph key that was extremely well built. Some of us got rid of the bakelite base and mounted the key on a nice piece of wood or brass (beware RF burns on conductive bases). I still have mine, decades after I quit being an active amateur.

After I graduated from being a novice, I still had a love for CW (Morse code). Not having the bucks for an electronic keyer in 1970, I acquired a used bug, the Vibroplex Original model, as shown at the right. These had a spring loaded weight that made dots automatically but it was up to the operator to make the dashes and spaces correctly. It took a lot of practice, almost as much as playing a musical instrument. I actually went to the local telegraph office and got tips on how to use a bug from the operator there. They used teletype by 1970 but the guy had been there for so long that he remembered how to use a bug and the trick of soldering a ball bearing to a screw to add more weight for use below 20 WPM.

Finally, after college, I could afford nice toys. Electronic keyers made dot and dash strings very well, and were easy to use to make perfect code. The Bencher paddle, shown on the left was the best of the best for use with the electronic keyer. I still have one of these in my closet. Both the Vibroplex bugs and Bencher paddle could be ordered gold plated if you had the money. I miss them all.

W8JK Antenna

The W8JK antenna design is a clever beast. Invented by Dr. John D. Kraus, W8JK, in 1937, it uses two dipoles, both driven and out of phase with each other, to create a directional antenna (no front to back ratio, though) that works on six bands (20-17-15-12-10-6 meters) and as a top loaded vertical on 40 meters (with a counterpoise ground). I used one of these at two locations and had excellent luck with it. The wire beam version, as shown in the top photo, is the cheap method (which I used) and you generally pick the direction that you want to work, which in WA is towards Europe, of course. In real practice it straddles the house so mine always pointed north-south and north over the pole to Europe worked for me. You need a balanced antenna tuner with this antenna and open wire or a low loss twinlead feedline. Here is a good article on the W8JK antenna by ZR6TXA. Dr John D. Kraus was an amazing physicist, inventing antennas for radio astronomy, building cyclotrons and working on anti-radar measures and ship de-gaussing during WWII.

Friday, October 4, 2013

1920s Shipboard Radio Station

This is a cool picture of an Italian shipboard radio station as seen on uv201.com

I guess they didn't worry much about electrical shock back then.That's the biggest knife switch that I've ever seen!

Click on image to enlarge.

Mother of All Radios

This is one awesome AM pre-WWII radio. The 1936 Crosley WLW Super-Power Radio was built to answer a challenge from Zenith who had just built the similar Stratosphere radio. Crosley also owned the radio station WLW, a 50KW AM station in Cincinnati, OH.

The Crosley radio had 37 tubes, six loudspeakers and 75W of power in a cabinet 58" tall, 42" wide and 22" deep. The chassis's were all chrome plated and the unit weighed 475 lb. There was an 18" woofer, two each 12" midrange speakers and three tweeters with frequency response form 20-20,000 cps. A microphone with a 25' cord was included so the radio could be used as a PA system. The radio tuned 540 kc to 18,300 kc.

The radio cost $1500 at the time. A new Ford then cost $652. This radio now sells for $55,000 on E-Bay.

For more details visit Radio Magazine Online.