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Tuesday, March 10, 2015

Shep on Parasitics and Troubleshooting: "That way madness lies"


You guys really have to listen to this.  This is culturally important.   And it is a great follow-up to SolderSmoke 173.
 
In this 1965 radio broadcast, Jean Shepherd describes his teenage struggles with parasitics and other technical problems in his homebrew 160 meter transmitter.

He describes the sound of parasitics on a signal, saying that they sound as if the signal is being attacked by "debauched erotic locusts."

He really nails it in describing the scornful, dismissive tone that many hams use in telling their fellow radio amateur that there are problems with his signal. ( I have recently been on the receiving end of this kind of treatment.)

He observes that no one is more worried, "than a man who has built something and can't get it to work." Indeed.

During a date with a girl from his high school, he is so obviously pre-occupied with his transmitter trouble that she tells him that something is wrong with him and that his mother "should take him to a doctor."

And he describes the joy that comes when you figure out the problem and get the thing to work.

The REALLY good stuff begins at about the 25 minute point.

http://ia310115.us.archive.org/2/items/JeanShepherd1965Pt1/1965_01_29_Ham_Radio.mp3

Shep was quoting from King Lear: "O, that way madness lies; let me shun that; No more of that."  In other words: "BASTA!"  That is what I have said about my 40 meter troubles.  My BITX 20/40 is now a BITX 20. 

EXCELSIOR!



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Monday, March 9, 2015

The Original BITX 20 -- Designed at 35,000 Feet in 6 hours, Built in India in 3 Days


 I came across what appears to be an early version of Farhan's description of the design and initial construction of the BITX 20  (see below); this version has some interesting information on the origins of this important rig.  The picture below shows the designer himself working on that first BITX20.  It is from a CNN video.  I know Farhan is sick of seeing this old video, so I present here only the shot of the designer's hands at work on the original transceiver.
 

Some thoughts from the designer, Ashhar Farhan, VU2ESE: 

    This transceiver was designed during a six hour flight from Europe with paper, pencil and the basic calculator built into my cell phone. It was soldered in three sittings over three days. Very little went wrong during the construction. It was one of those easy designs. The only mistake that I made during construction was that I soldered one of transistors in reverse. The design worked as ‘advertised’. I guess that extensively using feed back amplifiers provides designers with greater repeatability. Also, I realized, a little late in life though, that detailed forethought and ‘mental’ home-brewing is important for a clean design.
    The linear chain was initially unstable. It tended to oscillate in the 14MHz band as well as around 500 KHz. I traced the 14MHz oscillations to a choke that I was using at the output of the balanced modulator. It has been removed. The 500 KHz oscillations were because of excessive gain in the driver and pre-driver stages. From 5 ohms, the emitter degeneration has been increased to 10 ohms and better bypassing on the power rail has eliminated the oscillations.The receiver is as hot as I need it to be on 20 meters. Signals from USA, Europe, South Africa and of course India were heard with clarity reminiscent of a clean Direct-conversion receiver on the first evening. The transmitter is powerful enough for local rag chew and it is a modest challenge for DX. VU2PEP has an excellent two element beam at 20 meters at about 40 feet height. DX is easy for OM Paddy who uses the rig regularly. We netted LA2FKA within the first 20 minutes of firing up the rig.
    No, I don't offer PCBs. I don't repair rigs. I don't offer kits. I might do a PCB for this rig (I hate PCBs, they hamper experimentation).
    This transceiver is dedicated to the memory of OM Juggie, SK (VU2JH) who was a great organizer of India hams, he wrote technical articles in Electronics For You magazine about amateur radio, spurring many to take on ham radio as a hobby. He organized the Millennium Ham Meet in the year 2000. He was always searching for a good and simple homebrew SSB transceiver. He died young. He gave me my first morse key.

Jagdish, VU2JH




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Saturday, March 7, 2015

SolderSmoke Podcast 173: Pete's LBS Triumph and Bill's Tale of QRO Woe

SolderSmoke Podcast #173 is available:

http://soldersmoke.com/soldersmoke173.mp3

7 March 2015

Bench Report:   Pete's Progress on the Let's Build Something Rig:
http://www.jessystems.com/LBS_Detail.html
Ben's cool case for his LBS rig
Bill's Tale of Woe:  QRO troubles with the BITX 40
    -- QRO amplifier taking off on 40 (but not 17)
    -- Criticism and public humiliation on 40
    -- Troubleshooting
    -- Suggestions from Allison
    -- A sad realization about my VFO frequency selection
    -- Exorcism needed
    -- Pete suggests a digital solution
    -- Wow, my 'scope has an FFT!  Almost a spectrum analyzer!
    -- Some thoughts on trouble shooting
    -- On the meaning of "BASTA!"
The Spring 2015 Issue of Hot Iron http://www.walfords.net
More on Pete's KX3
Encouraging other hams to build
 
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Wednesday, March 4, 2015

Video of The Moment Colin Made his First Homebrew Contact With Australia



Our British cousins are not a wildly emotional people.  The word "phlegmatic" is sometimes used when describing them.  Stiff upper lip and all that. But as you can see at the 51 second mark in this short video, contacting Australia whilst using a new scratch-built homebrew BITX20 on battery power from a windy English hilltop WILL get those English fists pumping and those thumbs up.  The wind drowns out Colin's voice, but his gestures say it all.  Well done Colin!  Brilliant!  

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

Tuesday, March 3, 2015

Colin's BITX DX From the Field


That has to be one of the best-looking scratch-built homebrew BITX20s.  Pete and I agreed that it looks almost too good to take out into the field.   But that is where Colin took it.  His BITX was designed for Summits on the Air, and the radio gods rewarded him for his efforts with VK DX.  Well done Colin! 
 
 
Hi Bill and Pete.
Well it just worked out that weather was going to be bearable this morning but getting worse through the weekend. I'm really want to ramp up my SOTA score so I'm trying to get out as much as I can. I switched my plans to an early morning activation on one of the local hills. The hill, called Sharp Haw, is a little lump on the edge of the Yorkshire Dales, it's not very high at all, but it is worth 1pt for SOTA.
The early morning time window brought the possibility of VK QSOs via long path on 20m. I looked at the VOACAP prediction for propagation and it suggested a peak at 0800utc.
I was actually late getting up, my alarm clock batteries have decided they've had enough. Despite the late start, I still managed to get on the air by 0725, hearing a strong Australian accent on the power up frequency of the BITX, 14.200, was a good sign.
At 0737, I was called by VK1DI. I had to turn the AF gain up, but sure enough, the signal was workable and we exchanged reports, 55 for him, 33 for me. Within the space of less than 20 minutes, I had 4 VKs logged, the strongest being VK3DET, giving me a 56. The other two stations were VK3CAT and VK2IO. I also worked an Asiatic Russian station amongst others.
I'm over the moon, I might even apply for my SSB thousand miles per watt wallpaper!
I still find it magical that 25 volts into a bit of 7/0.2 wire can transport your voice across 15,000 miles! Amazing!
73, Colin, M1BUU

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Monday, March 2, 2015

Patrick, F6AWY, The SSB Carpenter (Homebrew Hero)

 
There he is:  Patrick, F6AWY, the builder of the beautiful wooden-case SSB transceiver featured here two days ago.   Born in 1945, Patrick has been melting solder since age 15. This picture made me think that there must be some connection between string instruments and homebrew genius:  Farhan plays guitar.   So does Pete Juliano.  I think it was Rick Campbell who was strumming the banjo at FDIM...  More about Patrick here:  http://www.araccma.com/f6awy-p821004 

 
 
Here is another of Patrick's projects.   He completely rebuilt an old Geloso AM transmitter.   Note the  markings on the front panel.  Signed with a dash of F6AWY panache! 
More about this project here:
http://www.araccma.com/emetteur-am-pas-a-pas-avec-f6awy-p820986

Translation tip:  Open these pages in Google Chrome.  Then, simply RIGHT CLICK on the page and select TRANSLATE TO ENGLISH.  


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Sunday, March 1, 2015

Homebrew Heroes at Rickreal Hamfest: W7ZOI and WA7MLH



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
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column