Back to the Barebones (Receiver)

My rehabilitation of homebrew 17 meter gear from the last solar cycle continues. Following the same path that I followed in 2001-2002, I will now move from DSB to SSB. I pulled out the little receiver that I put together way back when. It is a version of Doug DeMaw's "Barebones Superhet" (aka "Barbados Superhet"). I bought it on the net. It had been put together by a skilled builder on a FAR Circuits board. The fellow who built it had changed the IF from Doug's original color burst freq (3.579 MHz) to 5 MHz. He had also put in a varactor controlled VFO using a DC voltage multiplier to get more voltage variation across the varactor. I also think he had it built for 20 meters.

I converted it to a 17 meter receiver. I put in a VXO, using two crystals controlled by a panel switch. I also changed the caps in the filter so as to broaden the response for SSB.

As I was going through all these modifications, I turned to the USENET for help and advice. Dale, W4OP, came to my assistance. Little did we know how DETAILED his familiarity with my RX was:

"Bill N2CQR MOHBR" ...@virgin.net> wrote in message

news:22f6e3ee.0503292244.1b9a1481@posting.google.com...

> Dale: Wow, another Barbados RX builder. That was my first successful
> superhet project. I now have the one I built (still on 20), and this
> morning
> I got another one (the one built by someone else on a factory-made
> board)going on 17 with a VXO. I have a THIRD partially built Barbados
> RX board. If this
> keeps up, I'll soon have a BBRX museum.
>Hi Bill,

Did I sell you mine years ago? I seem to recall using a temp stabilized
varicap in a shielded enclosure for main tuning. It was done on a factory
board. Or was that a 6M xverter I sold?

Dale

Newsgroups: rec.radio.amateur.homebrew From: meara.lon...@virgin.net (Bill N2CQR MOHBR) Date: 30 Mar 2005 22:33:57 -0800 Local: Thurs, Mar 31 2005 1:33 am Subject: Re: Homebrew projects Dale: Wow, small world! Yea I think that is the one I'm working on. I think you also had a DC-DC converter to bring the voltage to the varicaps up. Very nice enclosure for the oscillator. I now have it percolating nicely as a VXO around 23 Mhz (for the 17 meter band). Bill - Hide quoted text -

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

Arduino and the Techno-Hippies

Phillip Torrone over on Maker blog has a good article about the Arduino, and what you can do with it. I especially liked his comments on the "techno-hippie" aspect of the Arduino project (“Arduino: baby-talk programming for the pothead”), and how it might be "Italy's Google."

Check it out:
http://blog.makezine.com/archive/2011/02/why-the-arduino-won-and-why-its-here-to-stay.html

Will we soon see Arduino's working alongside Raspberry Pi computers?

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

Homebrew Hero: Kazuhiro Sunamura, JF1OZL

In case anyone in the SolderSmoke community has not yet visited the site of Kazuhiro Sunamura... Be sure to check out his site. He has a really amazing range of projects:

http://www.intio.or.jp/jf10zl/

Here is the bio of OM OZL. As you can see, he definitely has the Knack, and clearly has the sharing attitude of a true member of the International Brotherhood of Electronic Wizards:

My name is Kazuhiro Sunamura. I am a 50 year old mechanical engineer, born in 1956. I am not an engineer in electronics. I have been interested in electricity and radio from the age of ten. For the last ten years, I have been active on my ham radio station JF10ZL. I have also written articles about my some of my radio projects in Japanese for the Japanese CQ Magazine. Now I have decided to get onto the internet and will take the opportunity of showing you my equipment and ideas. Please have a look at my schematics. I will be very happy if this material helps you with your own radio projects. I am a member of the J.A.R.L. affiliated Tsuchiura Club, the local ham club in my home town.

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

DSB QRP DX on 17

The solar flux index is now above 131 and the effects are very apparent on 17 meters. (I will pull out the telescope this morning to get some direct confirmation of improved solar conditions!) This morning I worked Daniel, F5BBD, with my little DSB rig with the 5 watt JBOT amplifier. Very solid contact. He gave me a 55. I hear Japanese stations in the evening. And I am hearing guys on 17 who I haven't heard since the last solar cycle: My friend Chris SM0OWX seems to be right where he was when we last spoke.

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

Find your Estes Rocket Catalog Online

On Wednesday we were all waxing nostalgic about 73 Magazine. (Did anyone figure out how to download ALL 511 of them?) I mentioned that I read many of the early 1970s editions from cover to cover. This morning I found on the Maker blog links to another publication that was burned permanently into my adolescent memory banks: The Estes Model Rocket catalog. Wow, I spent a lot of time studying the tech stats on the various rockets and rocket engines. (A8-3s!) I suspect that many SolderSmoke fans were also Estes enthusiasts.

Here are ALL the catalogs:
http://www.estesrockets.com/customer-service/full-catalog/

I think mine was the 1971 edition (above). I still feel bad about losing my Astron Big Bertha. And guilty about all the frogs I killed in the Astron X-Ray. I forgot all about the rocket with the 8 mm movie camera.

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

73 Magazine -- Online!

Some of my earliest ham radio memories are of 73 Magazine. Perhaps this has something to do with the electro-erotica cover shots of the early 1970s! I used to buy copies at "Electronics 59" in Spring Valley, New York. I remember struggling to understand the magazine: Why were these guys so obsessed about going to Navassa Island? Why was there a column entitled "Never Say Die?" Why was the classified section entitled "Caveat Emptor?" In time, all this would become clear to me. Occasionally, I'll come across an old issue and will suddenly remember it from when it first came out. I must have read these things cover-to-cover. (Jean Shepherd recalled reading even the grommet ads in the old QSTs.)

I really liked 73. It always had a zany, edgy, kind of "out-there" feel to it. Of course, near the end it went too far off the reservation (Bio-electrifiers? Faked moon walks?)

This morning QRP-L brings us the news that all the back issues are available on-line:

http://www.archive.org/search.php?query=collection%3A73-magazine&sort=-publicdate

I'm hoping that somewhere in there we will be able to find that early 70's article about the varactor-tuned DC receiver that I tried to build but couldn't get working.

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

A WWV Trick with the Drake 2-B

I was reading the October 1962 issue of 73 Magazine (we're always on the cutting edge here!). In the back pages a little piece from K4FQU (quite a call!) about the Drake 2-B caught my eye. OM FQU points out that by putting the bandswitch on 40 and the preselector at 10, WWV's 15 mc signal can be heard at the zero position on the 2B dial. It works! The familiar time signal beeps are coming through nicely here. It's fun to teach an old dog new tricks!

If you are looking for a 2-B, Bill KE5VZT alerted me to this one:
http://forums.qrz.com/showthread.php?325222-Drake-2B-with-Q-mult-amp-speaker

On the same page there is a review of a new Double Sideband rig from World Radio Labs -- the SB-175. Sounds like a winner!

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

"The Little Sweetheart" Receiver

Wow, what a beautiful piece of work! And a fascinating story behind it, with hints of wartime romance... Thanks to Mike AA1TJ whose very eclectic reading (Czech tech mags!) led us to this. Thanks also the Crypto Museum. Here is the link:

http://www.cryptomuseum.com/spy/sweetheart/index.htm

With more info here:
http://antiqueradios.com/forums/viewtopic.php?t=96007
And here:
http://antiqueradios.com/forums/viewtopic.php?t=96057

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

Amateur Radio Balloon Crosses The Pond (and the Continent)

Wow, congratulations to the California Near Space team. Their balloon flew from Silicon Valley, across the U.S., across the Atlantic and is now en route to Italy. As a former Azores APRS operator, I was pleased to see the APRS report from those islands. George, KJ6VU, of Sierra Radio Systems, was present for the launch.

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

Have An Oz Knack Christmas with VK2ZAY!

This is not the most flattering picture of our friend Alan, VK2ZAY, but I find myself forced to use it (again!) because of the Christmas light head-gear. Sorry OM.

I was thinking about Alan just the other day as I contemplated my broken Lafayette power supply (scroll down to the test gear article). You see, the meter in that little supply was destroyed by a trivial electric motor that Billy and I built a long time ago after a visit to Alan's amazing site. Don't worry Alan -- the broken meter is not your fault.

Once again proving that he is a true Knack victim and a certified member of the International Brotherhood of Electronic Wizards, Alan is doing an "Advent Calendar" of YouTube tech videos -- one short video each day during the Christmas season. I looked at a couple of them this morning. You guys will love them. Alan obviously has a deep understanding of the circuitry and a great talent for explaining how his creations work.
Thanks a lot Alan! Here is the link:

http://www.youtube.com/user/vk2zay

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

Seeing EM Waves with a Coffee Can

Thanks to Leif KC8RWR for alerting me to this. Amazing stuff, but somehow I think they need to get an Altoid tin into this project. You can sense the enthusiasm.

"Particles? We don't need no stinkin' particles!"

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

The "Snort Rosin" Test Gear Philosophy

Steve Smith, WB6TNL, and I often find ourselves on the same frequency:

Hi Bill,

After reading your latest blog post, I realized that you and I are somewhat kindred spirits. You successfully build and test relatively complex amateur radio equipment using the most basic and inexpensive test equipment.

As part of my business (land mobile radio) I own expensive and complex test equipment, however when I build and test homebrewed amateur radio gear I prefer to use inexpensive home-built or kit-built test equipment because that is what is generally available to most hams. My philosophy is that it is very important to impress upon beginning homebrewers the fact that fancy, complex test gear is not absolutely necessary to be successful in homebrewing.

Perfectly functional test gear can be built using only basic electronic tools. Certainly, homebrewed equipment might not have all the 'bells and whistles' of commercial gear and won't do everything 'automagically' but with careful calibration and learning how interpret the results, homebrewed test equipment can provide very accurate measurements.

One good example is your Palomar R-X Noise Bridge. Most every ham wants a MFJ 259B or Autek VA-1 antenna analyser but an inexpensive bridge like the Palomar or a homebrewed equivalent can provide many of the same measurements. Sure, a ham-band or general-coverage receiver is required to use a noise bridge but, by using -very- simple circuits, a very competent test receiver can be built using the most basic test gear. Even with only a good SWR meter and a little math thrown in, +/- Xj (reactance) measurements can be made (See http://www.qsl.net/n8xpv/ for information regarding "the 3 meter method" ).

One of my favorite resources for simple test equipment is Monty Northrup's (N5ESE} site: 73.......

Steve Smith WB6TNL "Snort Rosin"

From:

"solder smoke"

To:

"Steve Smith"

Great message Steve. Yea, I think the best troubleshooting tool is a real understanding of what is happening (or supposed to be happening) in the circuit and an ability to think logically about what could be causing the problem. Technical detective work. And indeed, that SWR bridge can tell you a lot.
73 Bill

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

Test Gear/Workbench Maintenance

I mentioned in the last podcast that I was going to take a break from construction projects and spend a little time fixing up tools, test gear, and the work bench. First up was my old soldering gun. I bought this thing almost 40 years ago! It is pretty beat up, but I managed to patch it up and it now works fine. Even the original light bulb works.

I use this little AADE L/C meter a lot, but was having trouble getting parts across the test terminals. So I soldered alligator clips onto one of the parts connectors that came with the device. Makes testing easier.

Just a little audio oscillator. Puts out .2 volts at 713 Hz. Useful for testing the phone rigs.

I picked up this little Lafayette power supply at a hamfest and found it quite useful. But then I managed to knock the needle off the meter while fooling around with trivial electric motor. Any ideas on where I could get a replacement meter movement, or on what value I should use?

Here is a wave meter that I picked up at the Kemptom Park rally in London. Apparently at one point all UK radio amateurs were required to have one of these devices. I'm tempted to chop it up for parts. That variable cap with the reduction drive looks promising. And could that meter solve my problem with the power supply (above). If anyone can think of a reason to keep this as a wavemeter, please let me know.

Further proof of my extreme retro-ness. This is what I use as a signal generator. A Heathkit SG-6. Older than me!

This is my scope. HAMEG. Supposed to be good to 10 MHz but of course I can use it at higher freqs (which I do). I need to upgrade. Any suggestions?

A very useful little square wave generator.

I need to make more use of this noise bridge. Lots of potential here.

Obviously a London purchase. Very useful little AF sig generator from the UK's equivalent of Radio Shack. My only complaint: No auto-off. I forget to turn it off and run down the two 9 V batteries.

Long time listeners will remember this device. This is the one in which I soldered in the chip upside down. It works fine on th 5 Hz to 100 MHz range. Dead on the 4 - 600 MHz position.

I bought this power supply at the Kempton Rally, then converted it into a current limited supply using a chip and a circuit provided by Tony, G4WIF. My daughter Maria helped paint the cabinet. Lots of soul in this little machine.

Just three meters. The middle (analog one) is still very useful, and has considerable sentimental value for me -- my wife got if for me when we were back in the Dominican Republic.
My version of the W7ZOI power meter. Mike, KL7R, and I built versions of this device back in 2004 or so.
This is Cappuccio. He joins me in the shack most mornings. I'm not really a dog person, but I'm growing fond of him, even though he occasionally eats resistors and capacitors.

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

Homebrew Ferrari

Speaking of homebrew motors, a number of people sent me this YouTube video about another intrepid European with amazing workshop skills. Great stuff. (It reminded me of the title of one of Jean Shepherd's books: "Ferrari in the Bedroom.")

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

The Woz's Early Exposure to Electronics

Here is what I was trying to --- hic-- say about Steve Wozniak --hic-- in Podcast #139:

From "Steve Jobs" by Walter Isaacson:

"One of Steve Wozniak's first memories was going to his father's workplace on a weekend and being shown electronic parts, with his dad "putting them on a table with me so that I could play with them." He watched with fascination as his father tried to get a waveform line on a video screen to stay flat so that so that he could show that one of his circuit designs was working properly. "I could see that whatever my dad was doing, it was important and good." Woz, as he was known even then, would ask about the resistors and transistors lying around the house, and his father would pull out a blackboard to explain what they did. "He would explain what a resistor was doing all the way back to atoms and electrons. He explained how resistors worked when I was in the second grade, not by equations, but by having me picture it."

This is clearly the approach to electronics that we see in the book "From Atoms to Amperes" by F.A. Wilson.

Mike, KC7IT, gave Woz a new title "the uber-knack-master of all time":

Woz is the uber-knack-master of all time, and always has been in my book. His Apple II design is a work of genius in getting ten pounds of function out of five pounds of parts.

One of many examples: Apple II was the first personal computer to use DRAM memory chips, which were brand new then and kinda scary even for us pros. DRAMs store data as charges on tiny leaky capacitors. Every 20 milliseconds or so they have to be refreshed.

Everyone else had counters and logic just for refresh. Woz arranged the Apple II's display memory, so reading out the pixels to the TV screen 60 times per second did the refresh too, at no cost in circuits or performance. The elegant design of a pure knack genius.

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

Hiccups in SolderSmoke 139

First there was the whistling of my SSS sounds (a speech defect that I had been blissfully unaware of due to a nullifying case of tinnitus!) Then, in SolderSmoke 139 the long-suffering SolderSmoke listeners had to put up with hiccups. Yea, around 53 minutes into the show there began an annoying series of hiccups. Being an essentially analog kind of guy, I'm sort of pleased to point out that these are DIGITAL hiccups, apparently introduced by the Audacity software during the actual recording (not when I converted the show to mp3). I've been having more than my normal share of road-kill computer problems lately. The laptop I'm using to record the show ate a couple of the recent episodes before I had a chance to upload them (I had to do them over -- that's very frustrating). So this time I was recording the show on a thumb drive. Apparently it was filling up as we got close to the end, which led to the hiccups. The worst part was that a hiccup came just as I was delivering a key quote from The Woz. (I'll post it.)

If anyone has any gear laying around that might with these problems, please send it my way. Obviously I could use a bigger thumb drive. An external sound card might be nice. I could probably use another laptop also...

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

30% off on SolderSmoke, The Book. December 7

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"
http://soldersmoke.com/book.htm

Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke

Our Book Store: http://astore.amazon.com/contracross-20

Messaging ET (METI), and Silicon-based Life Forms

My fellow beacon fans will like this one. The ultimate (REALLY ultimate) beacon! http://www.newscientist.com/article/dn21236-lets-build-a-beacon-to-tell-aliens-who-we-were.html?page=1

And then there is this article about silicon-based life forms. (At first I thought they were talking about us!) http://www.universetoday.com/91449/why-silicon-based-aliens-would-rather-eat-our-cities-than-us-thoughts-on-non-carbon-astrobiology/

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

SolderSmoke Podcast #139

December 3, 2011

http://soldersmoke.com/soldersmoke139.mp3

Halloween, Thanksgiving, and Billy's Birthday (on the range!)

Astro-Knack: CCD camera in the telescope. Solar astronomy.

Winter approaches: Shack heating by Heath, Halli, Hammarlund and Drake.

2B troubles on 17 meters.

Rig Re-Cycling: Rebuilding 17 meter rigs from the last solar cycle.

Azores DSB re-build: Oscillator troubles then adding a JBOT.

Manhattan style construction and the need for urban renewal.

Book Review: Steve Jobs. (Woz has the Knack!)

MAILBAG

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

An Inspirational Homebrew Motor from Spain

Bruce, KK0S, alerted me to this inspirational masterpiece from Spain. It is, as he points out, one of a number of really great videos about top level homebrew craftsmanship from Europe (remember the French homebrew tubes?).

Other comments from Bruce:
Did you notice that the calipers and micrometer this guy was using were seriously old-school. Totally manual readout. Not even a dial on that set of calipers! On top of that, his little lathe was manually fed. Notice in one of the shots, he is shown turning the cross slide feed wheel. No CNC anywhere. I can't be positive, but I don't think the lathe had a digital position readout either. This man is a machinist in the truest sense of the word. The Knack not only lives - it thrives!

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

Secret Listeners -- The Voluntary Interceptors

Jim, AL7RV, and several others sent me the link to this really interesting video about the British radio amateurs in WWII. Real "stiff upper lip" spirit in this video. Musn't grumble! Great stuff from Great Britain: http://www.eafa.org.uk/catalogue/5108

That regen receiver they showed looks a lot like the beast that I brought back from the UK with me. Once again, I am hearing the siren song of the diabolical regens....

Progress continues on my Indian-ized Azorean DSB transceiver (with JBOT amp). I now have the amp nicely stabilized (thank God!). Now I just need to get the output from the balanced mod close to the 1 mW PEP level needed by the amp. Should be done soon. And my cold seems to be going away, so maybe I'll be able to share my tales of JBOT derring-do in a podcast this weekend.

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

30% off on SolderSmoke, The Book. Cyber-Monday Sale. November 28

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

A Re-balanced Modulator for my Re-cycled Rig

My effort to bring my Azorean 17 meter DSB rig back to life continues. This is proving to be harder than I thought. I'm still taming my version the JBOT amp. It still seems to break into oscillation -- I think the oscillation freq is around 1 MHz. But I am making progress.

I had to go back and work on the balance modulator circuit. I really like the simple two diode singly balanced mixer circuit. But my original Azorean board had, like the oscillator board, been through a few too many rounds of modification and repair. I decided to start over. See above. I even came up with my own little innovation on this circuit. Doug DeMaw's original design called for a 100 ohm pot at the junction of the two diodes, with the signal coming off the tap. You adjust the pot to balance the circuit and null out the carrier. But I didn't have a 100 ohm pot. Lots of 1K controls were available, so I put in two 50 ohm resistors in place of the pot, then put the 1k pot between the diodes, with the tap to ground. This balances things out nicely. See below.

I hope to get a podcast out next week, but I've been suffering from a nasty headcold that would have introduced all kinds of weird audio effects.

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

The Bar of King Arduino

I'm not sure what I would do with an Arduino, but articles like this definitely make me want one! Here's one passage:

To make the board, the group had a specific, student-friendly price as their goal: $30. "It had to be the equivalent of going out to dinner at a pizza place," Banzi says. They also wanted to make it quirky, something that would stand out and be cool-looking to erudite geeks. If other boards were often green, they’d make theirs blue; while some manufacturers economized on input and output pins, they’d add plenty to their board. As a final touch, they added a little map of Italy on the back of the board. "A lot of the design choices are weird for a real engineer," Banzi says with a knowing laugh, "but I’m not a real engineer, so I did it in a silly way!"

Here's the article. Note the origin of the name of the device.

http://spectrum.ieee.org/geek-life/hands-on/the-making-of-arduino/0

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

Steve Smith (on the left) and Bill (with the filter)

Steve "Snort Rosin" Smith has been keeping me on the side of the angels (and the FCC regs) in the area of harmonic filtering. Today he sent me this Steve and Bill cartoon. Thanks Steve. Just what I needed as I prepare for my next attempt to get my JBOT (with filter!) to behave. Wish me luck!

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

Amplifier Woes -- Help me! Help me!

When I look in the mirror and I see a haunted, obsessed look in my eyes. My wife senses that there is something wrong in the ham shack. She is right. I have an amplifier that wants to be an oscillator. Help me exorcise these gremlins! Guys, this problem is holding up the production of the next SolderSmoke podcast.

My JBOT amp works fine into a dummy load, but when I connect it to an antenna, it gets unstable. Here are some more details of the symptoms:

I am running the JBOT with a 5 element (two toroids, 3 caps) low pass filter (designed by Doug DeMaw and approved by Steve Smith).

With the antenna connected, all is well UNTIL I raise the power out (by varying the input) beyond about 1 watt. Below one watt, the amp is working fine, and it stable. As soon as I hit the 1 watt point, the amplifier seems to break into oscillation. This does not happen into the dummy load.

The antenna is a simple dipole fed by coax. It shows a low SWR. Even when I put an antenna tuner between the amp and the antenna and bring the SWR down to negligible levels, the instability problem persists.

With the amp disconnected from all other circuitry other than the antenna and the power supply, if I just touch the input capacitor, it breaks into oscillation. This does not happen when the amp is working into the dummy load.

I've bolstered the power supply filtering and decoupling. No luck. I tried some de-Qing of the transformers. No luck.

Any suggestions?

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

Backyard Solar Astronomy

Over the weekend I took a break from JBOT amplifiers and did something I've been meaning to do for a long time: solar astronomy. I pulled out my old 4.5 inch Tasco reflector telescope and aimed it at old sol. I know, I know, this can be dangerous, but we were careful -- note that Billy is standing on the other side of the business end of the telescope. In his hands is the paper onto which we projected the solar image. I'd always wondered how I would get the sun into the telescope's field of view without risking my eyesight by using the finder scope. This turned out to be no trouble at all: I just looked at the shadow cast by the tube of the telescope and --using the shadow as my guide -- moved the tube until it was lined up with the sun. We snapped a picture of our results. I think our crude effort compared very favorably with the picture from NASA's Solar Dynamics Observatory. You can see the same sunspots in each image (ours is reversed because we were using a reflector). These images are from 12 November 2011.

Our picture

NASA's picture

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

"The Knack" on a Mysterious Island

Paul, W2IOG, sent a nice e-mail about a very early use of the term "The Knack": 1874 by Jules Verne. (What word did he use in French?). I took a look at the Wikipedia page and discovered that there was indeed quite a bit of "The Knack" on Lincoln Island:

"With the knowledge of the brilliant engineer Smith, the five are able to sustain themselves on the island, producing fire, pottery, bricks, nitroglycerin, iron, a simple electric telegraph, a home on a stony cliffside called "Granite House", and even a seaworthy ship. They also manage to figure out their geographical location."

Hello Bill,

I have been a listener to your Soldersmoke pod-casts for a couple of years now. I am also a regular reader of the blog as well as a long time victim of "The Knack". I was browsing an old book store the other day when I came across a beautifully illustrated copy of Jules Verne's book "The Mysterious Island" copyright 1920. I couldn't resist, and when I reached chapter nine of part one of the book I was really glad I had made the purchase. In the story, which takes place in 1853, castaways on an apparently uninhabited island are trying to make fire for the first time. After trying and failing to make sparks by striking stones together, two of the castaways try the following:

"Pencroft, although he had no confidence in the proceeding, then tried rubbing two pieces of dry wood together, as [primitive people] do. Certainly, the movements which he and Neb gave themselves, if they had been transformed into heat, according to the new theory, would have been enough to heat the boiler of a steamer! It came to nothing. The bits of wood became hot, to be sure, but much less so than the operators themselves.

After working an hour, Pencroft, who was in a complete state of perspiration, threw down the pieces of wood in disgust. 'I can never be made to believe that [primitive people] light their fires in this way, let them say what they will,' he exclaimed. 'I could sooner light my arms by rubbing them against each other!'

The sailor was wrong to despise the proceeding. [Primitive people] often kindle wood by means of rapid rubbing. But every sort of wood does not answer for the purpose, and besides, there is 'the knack,' following the usual expression, and it is probable that Pencroft had not 'the knack.' "

Congratulations on getting that 17 meter rig back on the air!

Paul W2IOG


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

Sunspots! QRP DSB contacts on 17 meters

You can see here why I had so much fun in the summer of 2001 with my Azorean Homebrew QRP DSB rig. And why I am now re-CYCLING (get it?) and refurbishing the 17 meter gear that I built last cycle.

I've had the DSB rig on the air yesterday and have worked seven stations (2 watts peak DSB to a dipole).

Back to the Future! Someone on QRP-L said the SFI was recently at 180! Go Sol!

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

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).

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

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

Snow Static

Related to our post about my new (old!) all-boatanchors heating system (see below), yesterday I had some really horrendous static. I think it was caused by the snow. A Google search on "snow static" brought me to this video (which Gregg in Finland found "shocking""). I liked the tuner and the neon bulbs too.

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