2012 Off to a Good Start: Balanced ATU Success!

2012 is off to a good start here at SolderSmoke HQ. I'm planning on putting up an 80-10 dipole fed with open wire (window) line. So I need a balanced ATU. A very simple link coupled design appears in lots of the antenna books and handbooks (1980 ARRL Handbook page 19-8, RSGB's "Practical Wire Antennas" by John Heys, page 86): Just a series LC circuit in the primary and another tuned circuit with a split stator variable cap in the secondary. The junk box was VERY cooperative: I found a big tuning coil (or might it have been two coils?) probably from an old Heathkit DX-40 or DX-60) -- that would work for the secondary coil. Then for the primary I found a smaller coil that would fit perfectly (with one layer of Gorilla tape) inside the secondary. I also found two really pristine 1000 pF air variables (I know, they can't handle much voltage, but, hey, that's one of the benefits of being a QRP guy, right?) I used the HW-7 as a signal generator and this morning did some experiments with different loads. You have to play around a bit with the taps on the secondary, but the ATU seems quite capable of matching loads from about 50 ohms up to at least 10K, and it works from at least 40 meters to 15 meters.

I found it very pleasing to see that SWR meter go down to 1:1. I'll now -- in the finest traditions of ham radio -- wait until the snow starts falling and the wind starts howling before I try to put an antenna in the trees.

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Homebrew Hero: Ashhar Farhan, VU2ESE

I wanted to start off 2012 with something inspirational, and here it is: Ashhar Farhan's work bench. I was visiting his site yesterday and found lots of good info, good humor and, indeed, inspiration. Be sure to check out his RF generator project. And the page that gives his thought on tools and test gear. All of it is wonderful -- you'll find lots of evidence of Farhan's long-term case of The Knack, his efforts to put "soul into his new machines" (his kids are mentioned frequently in his descriptions of his projects), and his obvious qualification for membership in the International Brotherhood of Electronic Wizards. I really like Farhan's efforts to design rigs that can be built with parts available all around the world -- a JBOT amp of his design is percolating nicely in my 17 meter DSB rig, and has been crossing the Atlantic almost every day.

As we were throwing a football around yesterday, I told Billy about Farhan. I mentioned that he lives in Hyderabad -- Billy thinks that's one of coolest city names on the planet and plans to work it into the plot of a novel he is working on.

Here is the site: http://www.phonestack.com/farhan/

Three cheers for Farhan! Happy New Year to all!

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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.

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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.

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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!

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"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

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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