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Saturday, September 1, 2018
Lasers. Big Scary Lasers. And a guy with THE KNACK
Here is another young fellow who shows all the signs of having "The Knack." I think his findings would be very useful for those involved in light beam communication.
Labels:
Knack Stories,
Laser,
Light Beam Telephony
Monday, August 27, 2018
Arduino Gets Command Line Interface
Will this make it easier to put programs into the the Arduino? Will this resolve the problems we've had when using an updated Arduino IDE with code developed in an earlier version of the IDE?
https://hackaday.com/2018/08/26/arduino-gets-command-line-interface-tools-that-let-you-skip-the-ide/
https://hackaday.com/2018/08/26/arduino-gets-command-line-interface-tools-that-let-you-skip-the-ide/
Sunday, August 26, 2018
More Homebrew Wisdom from Frank Harris, K0IYE
In Chapter 13A, Frank Harris writes:
The Vanishing Art
The 1986 ARRL Amateur Radio Handbook reported that hardly anyone was building homebrew ham receivers.... Out of hundreds of contacts, so far I’ve worked four guys, George, K7DU, Mike, NØMF, Biz, WDØHCO and Jack, W7QQQ who were using homebrew receivers for the QSO. Three of these receivers were made from vacuum tubes. George's receiver is a beautifully crafted instrument that looks like a commercial design from 50 years ago. All of these receivers had no trouble hearing me on 40 meter CW. I talked to one other fellow, Gil, N1FED who told me he had just finished a vacuum tube receiver. Unfortunately, it was performing so poorly he was still using his modern transceiver on the air. Gil told me he didn’t like transistors. I guess he found printed circuit boards and those pesky oscillations too much trouble. In spite of this pessimism, you CAN build transistorized receivers that work reasonably well. I built mine because I was intrigued by mysterious circuits like “balanced mixers,” “product detectors,” “cascode amplifiers” and “crystal ladder filters.” Before this project, I could recite the purposes of these circuits, but I had no “feel” for how they worked and why receivers are designed the way they are. What better way to learn than to build one?
Aside from the need to shield circuit blocks from one another, a homebrew receiver with a single big board full of discrete components has another problem. If you build the whole thing at once without buying a kit and pre-cut board, I guarantee it won’t work. To make homebrew stuff that works, you have to develop your own technology based on parts you can get and circuits you understand. Learning to think this way was difficult for me. Rather than “building a receiver,” I had to lower my sights and build one circuit at a time, e.g., “an oscillator,” “a mixer,” “an audio amplifier,” etc. Then I put the blocks together to complete my project. Some of these circuit blocks didn’t work the first time so I had to build a new block. There were various reasons the modules didn’t work. Usually, I wasn’t able to buy the exact parts used in the circuits I was copying. Or my craftsmanship or shielding wasn’t adequate. Sometimes I never did learn why one version of a circuit block was superior to another. By building my receiver using separate little shielded modules for each circuit block, I could replace a circuit block whenever I managed to build an improved version. Otherwise, I would have ruined the entire big board.
On rare occasions my circuits didn’t work because there were errors in circuit diagrams in QST magazine or in the handbooks. I found some serious errors in my 1979 ARRL Handbook and a minor one in my 1998 edition. Perfect editing is not possible, so we shouldn’t expect it.
GET THE WHOLE BOOK HERE (FREE!)
http://www.qsl.net/k0iye/
Labels:
books,
construction techniques,
Harris -- Frank
Saturday, August 25, 2018
Thursday, August 23, 2018
W2NBC's AM Boatanchor Video
W2NBC was booming in on 3885 kHz AM this evening. I took a look at his QRZ.com page and found this video. Very nice.
I've been on 75 meter AM with the K2ZA DX-100 and my new 135 foot doublet antenna.
Sunday, August 19, 2018
"From Crystal Sets to Sideband" -- Homebrew Wisdom from Frank, K0IYE (Free Book)
I've had Frank's book on the blog many times over the years, but it is a book that merits repeated mention. It is filled with great advice and homebrew wisdom. I found myself looking at it again recently, and at Frank's QRZ.com page. I came across lots of wisdom that I may have missed in earlier visits. For example:
From the QRZ page:
My version of ham radio is 100% scratch built equipment. I buy nothing manufactured for ham radio except log books...My rig is based mostly on the 1986 ARRL handbook. Modern designs in today's QEX and Handbooks are usually full of mysterious ICs. In my opinion, they don't qualify as homebrewing.
From his book (Chapter 15):
I was fascinated by ham radio, but I didn’t learn much about how sideband worked. I
had the impression that sideband was MODULATION FOR MILLIONAIRES and too
complicated to homebrew. The 1957 ARRL handbook’s opaque descriptions of “phase shifters”
and “balanced modulators” only confirmed my opinion.
If you are like me, you will have a devil of a time getting your SSB drivers to produce
intelligible speech without hissing and noise problems. All I can tell you is to keep your brain
mulling over your difficulties. Shield and filter your prototype until the darn thing works. Keep
careful notes so you don't make the same mistakes twice. Persistence will win in the end.
My sideband transmitters are still in the experimental category. You will find that it takes
a great deal of tweaking and fussing to get SSB tuned so it sounds good and doesn’t radiate on
unplanned frequencies. You won’t believe how many diseases your SSB transmitter will create
for you to conquer! Sideband is not a project for impatient people.
Foreword:
We homebrewers are nearly extinct, but there are still hundreds of us scattered around the world, some are even in the USA. Yes, there ARE American homebuilders! We’re rare, but thanks to the QRP hobby, the number is growing. Even if we homebrewers don't change the world, I guarantee you will enjoy learning radio technology and building your own equipment.
Foreword:
We homebrewers are nearly extinct, but there are still hundreds of us scattered around the world, some are even in the USA. Yes, there ARE American homebuilders! We’re rare, but thanks to the QRP hobby, the number is growing. Even if we homebrewers don't change the world, I guarantee you will enjoy learning radio technology and building your own equipment.
THANKS FRANK! Send Frank a thank you note: Frwharris@live.com
Labels:
books,
construction techniques,
SSB,
troubleshooting
Saturday, August 18, 2018
QSX! Hans Summer's New SSB Rig Revealed in South Africa
I liked this video. I liked Hans' description of his mechanical skills, and the way he has at times become a "human CNC machine."
This seems like a much more sophisticated rig than the QCX. I may be wrong, but QCX seemed to be essentially an analog phasing rig with a narrow CW audio filter. I kind of expected the SSB version to be a QCX with broader filter, but QSX is a different, more sophisticated, SDR rig.
Once again, three cheers for Hans Summers. We should all pay him to go to those summer conventions -- every time he does, something new and important for ham radio comes out of the trip.
Labels:
Kits,
SDR,
South Africa,
Summers-Hans
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