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Friday, August 14, 2015

Knack Story: Rupert Goodwins -- SolderSmoke in the Old Smoke (London)



Rupert with some sort of SDR rig
 
In addition to having a very cool name, Rupert Goodwins, G6HVY,  is a for-real tech guru:

I was delighted when Rupert posted some sage advice about how to deal with my recalcitrant amplifier.   He managed to include a reference to Mr. Spock in his message, helpfully noting that some of these amp problems would challenge the Vulcan's logical powers.  That made me feel better.  I sent a few words of thanks to Rupert and got back this really great "Knack Story":  

Hi Bill,
 
Well, all I have on HF amp instability is anecdote and half-remembered theory. But I do like the sort of challenges that building RF on the bench brings up - a problem worthy of one's attention proves its worth by fighting back! 

I've enjoyed Soldersmoke (or should I say Soddersmoke) for years now, and even if I haven't bought the T-shirt, have bought your book. I first inhaled the demon fumes when I was barely into double digits, and the addiction kicked in hard - I fixed my first radio, a valve (tube!) FM 1950s broadcast receiver using a soldering iron that was actually one of my father's wooden-handled screwdrivers heated on the gas ring of the cooker in the kitchen. My parents were mystified but supportive...

London is indeed a hard place to play radio. But that makes it doubly pleasurable when it works: it rather feels like you're operating under cover, a special forces op sneaking the signal out under the noses of the regime. I once had a birthday picnic on Hampstead Heath where I brought my SOTA beam and fishing-pole mast: the local constabulary turned up and were also mystified but not quite so supportive... "What if everyone did it?" they asked. "Oh, if only..." I thought but did not say. 
 
I do hope you can pacify your errant amp. Sometimes these things can be fixed by brainpower, sometimes by just mucking around until they get bored before you do. But normally I find that I've learned a lot when the problem's solved. RF isn't black magic, it's a gateway into another world that's marvellous and enthralling, but ours to know. I read a really good paper by Freeman Dyson, where he said that Maxwell invented modern physics, because his equations were the first to show that the real world of how things work is both beyond our natural experience, but accessible through thought and logic. The real entrancing thing about radio is that it proves this - we can talk across the world by translating our knowledge into a tiny handful of otherwise inert bits and pieces that tap into something utterly beyond our senses. And it's open to anyone who cares enough to try. 
 
How cool is that? (I had to go and find that Dyson paper again - here it is, if you're interested:  http://www.damtp.cam.ac.uk/user/tong/em/dyson.pdf )
 
(I also have an unshakeable and unhelpful addiction for obscure but interesting radios, as my QRZ page confesses. And things I helped design and build when I was an engineer are now in the NSA and Bletchley Park cryptologic museum collections. That, as they say, is quite another story...)
 
Anyway, thanks again for emailing - I'm thrilled to hear from you, and perhaps, who knows, one day we may make contact the way God and Maxwell intended - via QRP on a lively band while dodging the noise and bouncing our photons off the Heaviside Layers. 

Best 73s,
Rupert, G6HVY
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Rupert's QRZ.com page contains additional evidence of his Knack affliction and International Brotherhood of Electronic Wizards membership:
 
Other equipment here includes a Wireless Sets No 19 Mk III, an R1155, a Barlow Wadley XCR-30, an ICR-73, some PMR stuff on 4 metres, some old CB kit (shhhh!) and other obscurities. I like kit that has something different about it the 19 set, for example, is of course famous for its wartime role, but it was also the very first transceiver. The XCR-30 is really interesting, not only for being a high tech product of 60s apartheid South Africa (so a morally complex thing to own), but for having a very esoteric design that provides 0-31MHz coverage without bandswitching, very high stability and accuracy (you can generally pre-tune an AM broadcast station anywhere on the bands from the dial and be within 1KHz on switch-on, and all from a handful of transistors. There are stories to tell about all of my radios. 

Started in radio when I was too young to get my ticket, so was forced - forced, I tell you - onto CB radio, in the days when it was very popular and very illegal. Had a couple of crystal-TX, super-regen RX walkie-talkies (QRPp and RX so wide I could pick up Radio South Africa on the BC 11m band) to start with, thence bought a 'for conversion to 10m' populated CB PCB from a batch at Plymouth ARC Rally and just bunged a set of toggle switches on the PLL-02 divider inputs. This was the mid-late70s, when skip was high... Did the RAE ASAP after my 16th birthday, first legal amateur rig (I may have built things with 6V6s that may have made odd noises on the local Top Band AM Sunday morning net) was an Icom IC-2E. My richer friend, who was a G6E, had an FT-290R, which was obv. nicer but obv. deafer. "FT-290. IC-2E. I can hear him. He can't hear me." Used 19 sets at school, so have that addiction too. Since then, the hobby has been in and out of my life (like QTHs, wives, jobs and money), but the love of radio never has. 
---------------------------
I also understand that he once worked at a dodgy TV repair shop in the back streets of Plymouth and can still swap out a gassy PL509 with the best of 'em.

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

Thursday, August 13, 2015

W1JSB's Very Cool Portable Rigs -- RadioSet-Go!


Brad Smith alerted me to this.  Very cool.   Hanz W1JSB is churning out some amazing trail-friendly rigs.   I really like the tinted-translucent front panel. 

Here is the site for Hanz's company:  http://radioset-go.com/

Here is his YouTube Channel:  https://www.youtube.com/user/w1jsb/videos


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

Friday, August 7, 2015

Amplifier Woes! Instability at Low Drive Levels! (Video)



I have to keep reminding myself:  This is not "plug and play." These are not appliances. 

After I got my 40 meter problems squared away,  I was doing some testing on my beloved 17 meter BITX.   I noticed something weird:   With the CCI EB63A amp feeding my 17 meter Moxon antenna, as I raised the output of the BITX17 driver, at one point (at about half the max input power) the SWR would suddenly spike. Then, as I raised the drive level above that point, the SWR would go back to normal. 

I looked at it on the 'scope.   I can see the signal go very ugly at the mid-level drive point.  In the FFT display, I can see that there is a strong signal at around 435 kHz.  The 18 MHz signal seems to be riding along on top of it.  Take a look at the video above.

Additional clues: 

I see no signs of the 435 kHz signal at the output of the BITX 17.  It seems quite clean.

This problem disappears if I replace the Moxon with a dummy load. 

This problem does not show up if I feed the EB63A with my almost identical BITX20.   And I use the same LP filter on both 20 and 17 in the CCI amp.

Any suggestions?  Has anyone had this kind of problem? 

Allison and Pete have been helping me with this.  Thanks to both of them.  

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, August 4, 2015

The 1Watter


There are currently only 2 in the universe.  And they have been talking to each other.  Soon there will be more.  Many more.

http://www.kitsandparts.com/1watter.php

http://www.1watters.com/

http://www.k7qo.net/onewatter.html

Chuck Adams explains (via the qrp-tech mailing list):
 


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

Monday, August 3, 2015

Amateurs and the Search for Extra-Terrestrial Intelligence



Interesting article.   The author mentions a connection between SETI and the Homebrew Computer Club:


We had a SolderSmoke "SETI at Home" team.  Anybody know how are we doing?   

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

Saturday, August 1, 2015

Video of Curiously Strong Altoids Tin Frequency Counter



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

Pete is Having Antenna Project Problems -- Can you Help?




Our friend Pete, N6QW, has run into some difficulties in his antenna project.   The push-up/tilt-over mast he is working with doesn't seem to be up to the task.  Just look at what this is doing to him!  

Does anyone out there have suggestions on how Pete might easily get his 2 element beam up to about 30 feet without spending kilo-bucks?

The project is described on Pete's blog:


You could leave suggestions or ideas on Pete's blog, or in the comments section here, or e-mail them to soldersmoke@yahoo.com

Thanks.


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
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