JBOT Amplifier Installed in Azorean DSB Rig

I've been remiss in posting to the blog, but I have a good excuse: I've been melting solder. I have working on the installation of my new Farhan-designed JBOT amplifier in my old Azorean DSB transceiver. I'm really enjoying this project, and I now see it as the first in a series. My shack has a number of creations that were built during the peak years of the last solar cycle, but have since fallen into disuse. Many of them were partially cannibalized -- usually it was the RF amplifier that was taken out. The JBOT was just what I needed. I plan to refurbish all of these rigs, adding a bit of India to each one of them. This is very much in keeping with our "International Brotherhood of Electronic Wizards" ethos.

The installation went fairly well, but with all of the ups and downs that accompany this kind of project. The amp worked fine on the bench, fed with a signal generator and into a dummy load. But of course, life got more complicated when I installed it in the rig. Yes, it took off on me. This was no fault of the amplifier -- I just needed to add some additional shielding. It is working fine now. See above. I moved it out of center stage and put it off in the corner to avoid feedback problems. More discussion of this in the next podcast (maybe this weekend).

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Tony Sale and the Re-Building of Colossus

Steve "Snort Rosin" Smith sent us this, noting that "Tony Sale definitely had The Knack." As the Brits would say, "indeed."

http://mathdl.maa.org/mathDL/?pa=mathNews&sa=view&newsId=1195

Amazing info on Tony Sale's work here:
http://www.codesandciphers.org.uk/lorenz/index.htm

I got a kick out of this bit:

One reason for wanting to get Colossus working in 1996 was that for far too long the Americans have got away with the myth that the ENIAC was the first large-scale electronic digital calculator in the world. It was not, but they got away with it because Colossus was kept secret until the 1970s. As 1996 was the 50th anniversary o the switch-on of ENIAC I made sure that Colossus was rebuilt and working in Bletchley Park, just as it was in 1944.

There has been a stunned silence from across the water!

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

21st Century Ham Radio -- EDN Article

A few listeners sent this in. Thanks! Note the mention of AA1TJ's CFL light bulb rig!

http://www.edn.com/article/519742-Ham_radio_in_the_21st_century.php


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

First Flight in Electric Multi-copter

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Recreational Engineering

I like that term! "Amateur Engineering" always seemed to sound kind of scary, conjuring up images of bridges that don't quite stay in place. "Recreational Engineering" has a nicer, less ominous ring to it. I found this phrase at the end of this newspaper article on the Maker movement:

http://www.csmonitor.com/Innovation/Tech/2011/1101/Maker-Faire-Mad-science-for-the-masses/%28page%29/2


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Happy Birthday Arecibo! A Tour of the Radio Telescope

Yesterday I was listening (as I do each morning at 0635) to Garrison Keillor's "Writer's Almanac." (I use a beautiful old FM broadcast receiver that Rogier out in California sent me for my birthday.) Garrison announced that it was the birthday of the Arecibo radio telescope (it opened on November 1, 1963). I wanted to post something about this on the blog, but was running a bit late and didn't get to it. This morning I was greeted by an e-mail from Ken, KG6PO, alerting me to a really magnificent video tour of the Arecibo facility. Wow. This is truly amazing. You guys are going to love this one. Three cheers for Bob Zimmerman! As I watched, I got the distinct feeling that we were visiting Bob's shack, and that the dish was his antenna!

Please spread the word about this video -- it is a real shame that it has only received 757 views. Three cheers for the guys who filmed this. Beautiful work.

Links:

http://youtu.be/kQJawfbjpxw

http://www.youtube.com/watch?v=kQJawfbjpxw

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Pumpkin Pi and JBOT Gremlins

Maria wanted to go with a mathematical theme for this year's Jack-0-Lantern. Pumpkin Pi!

I have been chasing some gremlins and banshees around my old Azores 17 meter DSB rig. The JBOT Amp worked fine into a dummy load, but of course things got a bit more complicated when I put it into the rig and connected it to an antenna. It would take off (like a banshee!) if the load was at all reactive. I think this is the result of inadequate shielding and inputs a bit too close to outputs. But it all settles down nicely when I put a transmatch in the antenna line and tune out the reactance. I may just leave it this way.

Output is a bit low -- only about 1 Watt. I realize that at 18 MHz output should be dropping a bit, but I think I should be getting more. I THINK I'm giving it the recommended 1 milliwatt input. At some point I think Farhan mentioned the possible need to experiment with the number of turns on the secondary of the output transformer....

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20