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Sunday, August 12, 2018

Three Cheers for the uBITX! Keeping problems in perspective...

This morning I was looking at Farhan's uBITX page.   He got philosophical at the end of the circuit description: 

As a fresh radio amateur in the 80s, one looked at the complex multiband radios of the day with awe. I remember seeing the Atlas 210x, the Icom 720 and Signal One radios in various friends’ shacks. It was entirely out of one’s realm to imagine building such a general coverage transceiver in the home lab.
Devices are now available readily across the globe through online stores, manufacturers are more forthcoming with their data. Most importantly, online communities like the EMRFD’s Yahoo group, the QRP LABS and BITX20’s groups.io community etc have placed the tribal knowledge within the grasp of far flung builders like I.
One knows that it was just a matter of breaking down everything into amplifiers, filters, mixers and oscillators, but that is just theory. The practice of bringing a radio to life is a perpetual ambition. The first signal that the sputters through ether, past your mess of wires into your ears and the first signal that leaps out into the space from your hand is stuff of subliminal beauty that is the rare preserve of the homebrewer alone.
So true!   Over on the BITX.io group there is a very interesting discussion of the extent to which the uBITX is in compliance with FCC and ITU specs on harmonic and spur emission. In this discussion, I think it is important to remember the reason Farhan created the BITX rigs:  The goal was to get today's radio amateurs out of their Yaesu-Kenwood-Icom appliance rut, and get them involved with the circuitry, to get them to modify and improve the rig.   And that's precisely what is going on now.  
It was well known that dual conversion is riskier than our old familiar single conversion architecture -- when you throw another mixer and oscillator into the rig you open the door to  problematic spurious signals..  But dual conversion holds out the promise of general coverage.  And the advantage of that is quite evident in the uBITX.  Mine is on right now and I can switch from band-to-band with a press of the tuning control. This is nice.  So a spur has been discovered -- solutions are already being offered.  That's the spirit!   And it looks like the low pass filters might not be as effective as hoped.  This may be a simple matter of board layout and relay use.  That is clearly quite fixable.
So let's remember that this is not plug-and-play ham radio. This is more of a collaborative, homebrew, open-source hardware/software project.   The uBITX may be closer to true homebrew than many hams are accustomed to.  That was the whole idea. 

Patience is a virtue
Possess it if you can 
It is never held by techies
And seldom held by hams  


Tuesday, August 7, 2018

Where it belongs: S38E in a Zoo


Hey fellas,
Hope this finds you well.  Spent the day with my family at a zoo.  They have a neat African exhibit that includes many small huts for shade and to give the feel of the African bush.  Each was outfitted with items kne would expect to find in a distant bush camp... Gear, etc.  Many had semi modern radio receivers. 
But one...  One had a well worn and rusting Hallicrafters S38E.  The rig y'all love to hate... Lol. It is secured to the shelf and as far as I know stays their year round; partially open to all the wonder weather Michigan can throw at it. 
I got a kick out of it, thought you may as well.  
Hope all is well.
John in Michigan 
KE5ETX
--------------------
John:  Finally, a good place for these things.  Museums. Or Zoos.   We should organize a collection campaign, perhaps with free pick-up and tax deductions.  

Here is a no-kidding story.  We had a family reunion last month.  I met a cousin I hadn't seen in 40 years.  I had given him an old S38E so he could listen to SW BC.   I asked him if he remembered that radio.  "Yea, I sure do -- It almost electrocuted me!"  
73  Bill 
------------------



Monday, August 6, 2018

VA3IAW's BITX 40 Box. Ugly? I don't think so.


Al VA3IAW thought he had a shot at the "Ugliest BITX 40" award, but I shattered his dream by declaring it a thing of beauty.  He made it from PC board material and 1/4 inch angle brackets.  That's a paint stirrer supporting the mic element and the PTT switch.   Al might want to use shielded cable for the mic if the waterfall policeman on 40 meters detect RF feedback and freak out. 

Sunday, August 5, 2018

The CHIME Radio Telescope and Fast Radio Bursts



The new Canadian radio telescope is very interesting.  It has a great name for a radio telescope:  CHIME  

And it it always nice to come across a reference to the Parkes Radio Telescope.  

More info here: 

https://www.theregister.co.uk/2018/08/03/fast_radio_burst/

And here: 

https://en.wikipedia.org/wiki/Fast_radio_burst

Good luck on getting a QSL from the FRB station.

Saturday, August 4, 2018

WA4GEG's Beautiful HB Transceiver


http://www.hamradiobug.com/homebrew.html

Pete spotted this.  Beautiful work. I noted that Byron hasn't used the Manhattan style of construction.  This makes his work look a lot neater, but it makes it harder to modify and debug the circuitry.  On the other hand, OM Byron is obviously so good at this that his circuitry probably doesn't require any debugging or mods. 

The red S-meter and freq counter give it a slightly menacing appearance.  Very cool. 

Monday, July 30, 2018

Wow. Mr. Carlson's New Old-Time Radio and Test Gear Lab. VE7ZWZ -- Homebrew Hero



It has been a while since we last visited Mr. Carlson's lab.  As always, we found it amazing.  The awesomeness just keeps increasing. Previous visits: https://soldersmoke.blogspot.com/search?q=Carlson

As was the case before, this is really almost too much.  THREE DX-100s in the shelves.  A massive collection of tubes, some sorted, some un-sorted.  But don't worry -- Paul has a good memory and remembers where everything is.  I believe him. 

For his amazing shack and workshop(s) and for his willingness to repair old-time test gear, Paul VE7ZWZ clearly deserves homebrew hero status.  

Thanks Paul. 

Sunday, July 29, 2018

On-Board your Arduino Board with an HCC Board



Nice, but the toaster oven is kind of scary. 

Friday, July 20, 2018

A Rig with Maximum Soul: The 5 Band Transceiver of Glenn KU4NO

That's the front panel.  Glenn's kids and grand kids liked sitting on his lap while he played radio and putting stickers on it

This is one of the best HB2HB contacts I've had.   I was just getting ready to sign off on 40 meters when I heard someone calling me. It was KU4NO.  I thought I'd just give the OM a quick report.  Then he said, "My rig is homebrew too."   And wow, it is indeed!  When he said this my first thought was that maybe this was a kit rig, but no, it turns out that this rig is the scratchyist of scratch-built rigs -- true hardcore hardrock homebrew. 

I checked my log.  I had worked Glenn once before, in December 2001.  I was in the Azores.  And he was using this same rig.  Glenn told me that for all these years, this has been his ONLY rig.  A friend gave him a modern commercial rig, but he prefers this one.  I understand completely.  

At first, Glenn made me promise not to share the pictures with anyone. He seemed a bit embarrassed by his creation.  I told him that SolderSmoke readers would appreciate his rig and see the value of it. I explained that we all have soldering iron scars on our fingers, and clothing that has been stained by ferric chloride.  We LIKE ugly.  It took some persuasion, but I got  him to agree to let me share this with the group.  

Glenn reports it is based on a "5 band transceiver" circuit in the 1976 or 1977 handbook. (i don't have one and can't find it on-line -- can anyone get us a copy of the schematic and article?)

So I say THREE CHEERS for Glenn KU4NO and his homebrew 5 band transceiver.   For me, the stickers are the most important feature of this rig.  Please e-mail me your comments on Glenn's rig - in an effort to let him know how much we appreciate and understand his effort, I will pass them on to him. I wish more hams would follow his example. 

Glenn wrote: 

Oh well I'm not too concerned about who sees it. 
I just wouldn't want to cause anyone to follow my example. 
Maybe you could call it "a tornado goes through a junkyard."
Just kidding around ...no restrictions...I'm sure it will be forgotten soon ..... but I will be innocent of any harm caused by it. 
Its the only rig I've ever owned when we contacted before it was with it. 

The inspiration article in the 76 or 77 handbook is worth a look.  
The VFO tuning cap and mount came from a CB "slider" one of my brother-in-laws gave me  it seems to work well
 
Glenn


Picture Above:  top view upper left power out two IRF 510s from w2eby ( I think) 30+ to 60+ watts across HF love this circuit, small board connected at right angle is 1/2 watt driver from Harrys Homebrew page 2n2222 driving 4 2n2222s beautiful circuit
lower left power transformer 
one of two wafer band switches in middle   ....  under wafer switch is hf mixer and single balanced mixer to generate ssb
 LO from progressive receiver top right ... heat sink just to left and lower unused voltage regulator
  RF amp and wafer switch lower right used for transmit and receive
 

LO tuning cap and hf mixer modulator circuit
 

 RF amp

 Crystals for mixing, BFO, old detector circuit.  Old circuit that repeated CQ call, chip from Radio Shack

Some micro relays ...... audio amp at bottom and two switchable compressor circuits one using an SL 1626 and one lifted from a President model CB radio  and some filter caps
 

New IF AGC audio detector uses three ca 3028As from 67 handbook schematic is wrong can you find the mistakes? it was printed wrong twice i use an s meter with it


Close up of power output and lower left  rf output filters  
 


Thursday, July 19, 2018

Homebrew Juju -- HB2HB


Oh man, last night the Radio Gods were on my side.  I only had about a half hour on 40 SSB, but I had some really nice QSOs.   WB2HJK George in NYC was very interested in the BITX revolution.  W3BT in Philadelphia is a kind-hearted OT who ran an ENORMOUS Yagi atop a row-house in the city -- the antenna extended over the street and TWO of his neighbors houses.  Never had a TVI problems. FB.  SS listener WA3O Mike called in -- Mike is the fellow who gave me my HW-7.  Mike has been running his uBITX into a homebrew 500 watt LDMOS amp. FB Mike.  

Then the real miracle happened.  Just as I was about to throw the switch, Glenn KU4NO called.  I decided to give him a report.  But then he said something I rarely hear:  "My rig is homebrew too!"  I checked the log -- I had spoken to Glenn before, but our last QSO was in December 2001.  I was in the Azores.  Glenn was on the same homebrew rig.  We had a nice talk about his rig.  FB.   

Glenn told me that in all his years on the air, he has only had a few contacts with other homebrew stations.  He had a list of them:  1) W4ZCB, 2) N6ORS (FB! SS Listener!), N2CQR ("No wait -- I just heard you but we didn't talk.") and W2JUQ.  I will tell Glenn that he needs to add CU2JL to the list -- that was me in 2001 and I was indeed homebrew DSB.) 

To top it all off, Dino KL0S was listening and recorded the final part of the QSO.  See below. (The video might take a few minutes to load.) 

In honor of that FB night on 40 I am re-posting the animated GIF of my BITX-17 build.  I hope it doesn't make you seasick!  

Also, I think we need to add a term to the SolderSmoke lexicon:  Juju.   As in Homebrew Juju. See:  https://en.wikipedia.org/wiki/Juju   Right?  What do you think Steve Silverman? 




Saturday, July 14, 2018

Homebrew Tuner for Doublet Antenna



For now, I've put the Moxon project on the back burner.  I will take it up again once Old Sol starts showing some spots.  In its place a 135 foot doublet is going up.  I got at a hamfest a while back.  (It is the only HF antenna that I ever bought!) It is the SPI-RO Manufacturing Company's Model A-10.  It came with 100 feet of 450 ohm window line.   It will be up on the roof soon.  

Today I put the tuner on the wall in the car port right outside the shack. I even built a little shelf for the SWR meter (used one of those Whole Food grilling planks!).  I put a 25 ohm resistor where the feed line will connect.  I was able to tune it up on the two bands I tried: 40 and 17.  

There is a smaller coil inside the big one -- the smaller coil resonates with the lower variable cap. 

You can see all the homebrew rigs in the background -- waiting patiently for the antenna.  

I actually built the tuner back in 2012, but never used it.  Description here: 


I will try to provide a schematic and more details soon. 






Tuesday, July 3, 2018

The Moxon Files from L.B. Cebik W4RNL



I had thought that the Cebik files were lost to us in some sort of legal copyright struggle.  But in my effort to better understand the Moxon antenna, I found a real treasure trove of Cebik's writing.  These should all be saved somewhere safe. 

I especially liked his description of the evolution of the Moxon antenna.  Les Moxon was apparently very unAmerican in his emphasis on reception (not transmit gain)  as the main benefit of the beam antenna.  He also sought to avoid superfluous luxuries like rotators, but Cebik hints that rotators have become an important part of our American way of life.   Indeed.   
Before I found these files I had been on the verge of giving up on efforts to replace my storm-damaged Moxon.  After all, solar minimum is still ahead of us.   But after reading OM Cebik's articles I have decided to build a 20 meter version and place it above the center point of a 130 foot doublet.  I will have the best of both worlds.  

http://www.antentop.org/w4rnl.001/mu0.html

http://www.antentop.org/w4rnl.001/mu2a.html

L. A. Moxon, in his HF Antennas for All Locations, provides the essential clue: "the main benefit [of a beam] accrues from the reduction of interference during reception, though the 4 to 6 dB gain provided by typical amateur beams is an important bonus and probably the reason which carries the most weight with the majority of amateurs."(2)Here is a theory of beam operation quite unAmerican is style: instead of gain, Moxon strives for front-to-back ratio as the most crucial aid to ham operation. His statement is an affirmation of the "good ears" theory of operation. Even more, it forms the basis for his rectangular improvement upon the VK2ABQ square.
...
 Moxon prefers matched elements, tuning each of them to optimum performance remotely. That way, he can reverse the beam and do away with expensive and maintenance-intensive rotators. However, rotators are a way of life in the U.S. (a TV rotator will likely handle a 3-band Moxon beam), and there are many uses for portable beams that are hand-rotated or fixed in the field. Thus, I decided to continue the exercise in unequal element lengths.

http://www.antentop.org/w4rnl.001/mox20.html

Finally, a treasure trove of Cebik's writing: 

http://www.antentop.org/w4rnl.001/radio.html


Sunday, July 1, 2018

VU3XVR's Assembly Language 1K AtTiny-Si5351 VFO



Although Ram VU3XVR's project is in the digital realm, his barebones approach to the bits and bytes is, for me, very appealing. He takes a Si5351 and runs it with ATtiny13 with only 1k of space.  He makes intelligent use of every bit of that space.  He reveals his overall approach to rigs when he states in the video that his VFO will NOT have the traditional glowing numeral frequency readout because those bright lights can be so annoying and distracting.  I'm with your Ram!  Well done OM. Simplicity is a virtue. No more trouble with the Arduino and its fickle IDE.  No more agonizing visits to the Si5351 library.   

I see lots of applications for this little circuit.   Ram mentions beacon transmitters.  

He provides details here: 

https://vu3xvr.blogspot.com/2018/07/si5351-dds-clock-generator-using.html   

Saturday, June 30, 2018

Tom Swift had The Knack


Thanks to Richard for alerting us this important piece of Knack history.  Not bad for 1910.  You can see Tom's shack and antenna in the cover image (above).  I don't think he was going for a fan dipole.  He built the kind of multi-wire antenna that was in fashion in the early days of radio. 

The full text of the book is avaialble free on-line.  The radio fun begins in  Chapter 20: 

Bless my door knob, this was a lot of fun! 

Bill, 

I am certain I missed the origin of “the knack” as used on your blog. I, wonder, however, if in your youth you read Tom Swift novels? Although now they seem somewhat politically incorrect, I feel that the word may have, for our purposes, evolved there.

In the first novel, “Tom Swift and His Motor-Cycle” (sic) Tom repairs a butter churn’s “system of  cogs and handles.” When praised for his abilities he declares, “It’s just a knack.” Stick with me.

In a later novel, written around 1910, “Tom Swift and His Wireless Message” Tom is shipwrecked on an ebbing volcanic island. He saves the day by constructing a transmitter and receiver from the wreckage of his plane,  even though he “did not have the magnets, carbons, coherers and needles” needed. He strings “ wires from the top of the dead treed, to a smaller one, some distance away, using five wires, set parallel, and attached to a wooden spreader, or stay. (Fan dipole?) The wires were then run to the dynamo, and the receiving coil, and the necessary ground wires were installed.” Then,”once the impulses, or electric currents, are sent out into space, all that is necessary to do is to break, or interrupt them at certain intervals to make dots, dated and spaces.” He sent “C.Q.D. (come quick—danger) even though a “new code has been instituted for them, but I am going to rely on the old one, as, in this part of the world, the new one may not be so well understood.” Needless to say, a ship hears, responds and rescues the crew.

That”s “the knack", alright!

Never give up, and 73.
Richard, KD0NPM


Friday, June 29, 2018

Two Videos from Other Kinds of Workshops -- Dobson Makes a Telescope, Peter Builds an Airplane


Above you can watch a video showing the legendary John Dobson making a big telescope. Born in Beijing, Dobson is the former Hindu monk who left the monastery to show people how to make big telescopes out of shipping tubes and port-hole glass.  Think of it as the BITX of amateur astronomy.  Dobson is the founder of the "sidewalk astronomy" movement -- that's when you set up your 'scope on an urban sidewalk and show the wonders of the universe (or at least the solar system) to passers-by.  We did this in London with Saturn.  (Some of the cynical Londoners couldn't believe it was real -- they thought I had a transparency in the scope tube.) Dobson developed a very simple and popular method of mounting telescope tubes -- the "Dobsonian" method.   

More on Dobson here: https://en.wikipedia.org/wiki/John_Dobson_(amateur_astronomer)

Below you can see a short update on Peter's homebrew airplane. 

Monday, June 25, 2018

Dust Storm on Mars


Damn.  Just as Mars gets close enough for me to see something with my 6 inch reflector telescope, a massive dust storm hits.  I was out there this morning at 0430 local.   Mars was bright and red in the southern sky, but when I got it in the telescope's field of view it was like looking at a red version of Venus -- just the disk, with no surface features visible.  The before-and-after pictures above (taken with far better equipment than mine) shows the extent to which the dust has obscured things on Mars. 

But Sky and Telescope reports that the Martian skies may soon be clearing.  Hooray!  


Sunday, June 24, 2018

On Field Day: The Marine Corps Antenna Manual


Don't let it be said that SolderSmoke made no contribution to Field Day!   Here is the USMC Antenna Manual.   Looks like there is lot of good info in there.   

https://www.marines.mil/Portals/59/Publications/MCRP%208-10B.11.pdf?ver=2017-03-15-092827-423

Saturday, June 23, 2018

SolderSmoke #205 Solstice, Mars, Antennas, Displays, Phasing Fix, VFOs, Lexicon, MAILBAG


June 23, 2018

SolderSmoke Podcast #205 is available:  

http://soldersmoke.com/soldersmoke205.mp3

-- Summer solstice.  Mars Observations.  Graduations.  Internships.  Fathers Day.

-- Antenna Angst:  Pete's tribander and Bill's Moxon.  Insulation and resonance?

-- Pete's work on color displays. 

-- Bill goes back to fix up older projects:  

-- Fixing the Frankenstein Phasing RX.  Found an open choke!

-- Tightening up the HRO Dial. 

-- Achieving Juliano Criteria stability on a BITX20 VFO. 

-- Lexicon additions:  "Scratch Built"  "Hardrock Radio"  

https://english.stackexchange.com/questions/39551/where-does-the-saying-made-from-scratch-originate

-- PastaPete:  http://www.pastapete.com/

MAILBAG: 
Bob Crane W8SX Corrspondent at FDIM
Ralph AB1OP  Building LBS
Bruce KC1FSZ  Digital Pot
Jason W5IPA uBITX in Juliano Blue
Rogier KJ6ETL  ON THE AIR WITH A uBITX
Special thanks to Tim Walford for 25 years of Hot Iron.  






Thursday, June 21, 2018

"Hot Iron" #100 -- Thanks Tim Walford!


Tim Walford, G3PCJ has put out issue #100 of Hot Iron, the Journal of the Constructors Club.  That my friends is a long time publishing a quarterly.  25 years!   And it is a wonderful publication, filled with ideas and inspiration.  

Tim tells us in #100 that he is passing the baton (the Hot Iron?) to Peter Thornton, G6NGR who will keep the iron hot from here on out.   Peter is looking for contributions for issue #101.  Please try to help him out.  

Thanks again to Tim.  Good luck with the farm and the house moves.  


Tuesday, June 19, 2018

Digital Pot


No, this is not some on-line mail order thing.  Bruce KC1FSZ has done something that I find both amazing and horrifying:  he using a "digital potentiometer"  as the AF gain control in his BITX.  Remember when pots were simple and pure, when they were just a metal wiper that ran across a crescent of carbon of increasing resistance?  Well, those happy days are apparently behind us my friends.   What now?  Will we have endless discussions about where to find the driver for the 10k pot?   Will Facebook or Amazon or Microsoft secretly seize control of the data on our AF gain, perhaps to sell us hearing aids?   But enough of my ludism.  Good going Bruce.  AGC beckons. 

Hi:

I've built a few BITX rigs from scratch now and I'm starting to move to a modular approach using fabricated PCBs to make it easier/faster to build/mix/match the stages.  My audio amplifier module is based on the LM386.  I know others have moved away from this chip, but it still works for me.

I've added one feature to my audio amp stage that opens up some good possibilities.  Instead of the traditional potentiometer between the AF preamp and the LM386, I've inserted a digital potentiometer (MCP4131-103) that is controlled by three extra pins on the microcontroller.  The digital pot lists for $0.81 on Mouser so it's no more expensive than a physical pot and it's way more versatile.

Why do this?

  • The module is quick to make if you're building a lot of rigs.
  • AF gain can be controlled via the CAT port.
  • AGC control can be done in software.  This enables all kinds of fancy AGC "attack" and "release" controls that can be seen in the docs for commercial rigs.
  • This is an enabling feature for remote ops, which is why I did this in the first place.
  • AF gain can be controlled using the same encoder (different mode) as is used to control frequency, etc. if you wanted to build a more compact rig.
The board is shown below.  This is one of my first forays into KiCAD/PCBs/etc. so it's probably not as "tight" as it could be.  Also, I'm using through-hole components so it's old-school building.  But the board only costs $7 on OSHPark and it's pretty quick to wire up.  Anyone who wants to order one from them drop me a line and I'll send you the link.

Schematic below.

73s,
Bruce KC1FSZ




Sunday, June 17, 2018

Peter's New Airplane



Again.  Amazing.  What a great workshop.   Note his comments on the importance of DESIGNING FIRST, THEN BUILDING.  Words to live by my friends, words to live by.  Read and heed.  

Tuesday, June 12, 2018

Video on PCB Factory in China



This factory is a LONG way from Manhattan -- both from the island and from the technique.  

How about some Juliano Blue PC Boards?   

The machine that automatically checks for bad connections was especially amazing. 

And the boards are made in 24 hours, with 3 day shipping to the U.S. 

Sunday, June 10, 2018

"First Man" Neil Armstrong Movie Trailer



I think Ryan Gosling is a good choice to play Neil Armstrong.  It looks like this movie will deal with the "right stuff," a concept somewhat related to "the knack." 

Saturday, June 9, 2018

Another Wood Box BITX! KC1FSZ Abandons Al-Fresco but Continues with Wood


'Tis a thing of beauty.   I like the wood.  And I like the hood.  The handles are a nice touch.  A fitting follow-up to its al fresco organic origins.  

Hi Guys:

I know there was a view that my giant BITX was supposed to be left out in the open, but I’m going to try to attend my local club’s Field Day festivities this year and the 4 foot long “planker” was pressing the limits of portability.  So I moved from the shack to the wood shop and built myself some custom cabinetry.  I think it looks a bit like an IC-73000 now don’t you think?  OK, maybe not.  

There is a hinged door at the top and shelf levels inside for the different parts of the circuit. The power supply and PA section are mounted on the bottom which can be removed for accessibility/serviceability.   The whole thing weighs about 10 pounds!!

73s,

Bruce KC1FSZ




Sunday, June 3, 2018

Understanding Antenna Directivity -- Help from Canada



I am in the process of repairing my beloved 17 meter fishing-pole Moxon.  It was taken out of service by the last Nor'easter of the winter.  This repair has caused me to review the theory behind antenna directivity.  I find there is a lot of "hand waving" in the explanations of how directivity happens:  "You put a reflector element next to the antenna.  And it REFLECTS!"   You are left wondering how that reflection happens.  

The Royal Canadian Air Force made a video that does a pretty good job of explaining how the reflector reflects.  See above.  Thanks Canada!  

While we are talking about antennas,  I wanted to alert readers to a really nice antenna modeling program that is available for free.  It is called 4nec2.  You can find it here: 
http://www.qsl.net/4nec2/   There is a bit of a learning curve, and I am still climbing it, but I can see how this software would be very useful.  It has an optimization feature that runs the antenna through many versions and tells you how to optimize for F/B,  gain,  SWR, or whatever you want to prioritize.  

I have discovered that my Moxon was resonant below the 17 meter band.  In other words, the antenna elements were too big.  About 3.6% too big according to my calculations.  This may be the result of my using insulated wire for the antenna elements.  Apparently the MOXGEN software assumes the use of uninsulated wire.  I'm thinking that an easy way to deal with this would be to use the frequency 3.6% above my target frequency and then use the dimensions given my the MOXGEN program.  Any thoughts on this plan? 

What a shame that Cebik's web sites have all disappeared.      

Friday, June 1, 2018

INTERVIEW: Bob Crane Talks to Jack Purdum W8TEE at FDIM. Definition of "Homebrew."


Jack Purdum has been making enormous contributions to the radio art.  His background with digital technology has opened many doors for homebrewers, especially through his books on the use of the Arduino microcontroller.   I think his new "JackAl board" is really going to shake things up.  I was glad that our correspondent in Ohio, Bob Crane W8SX, caught up with Jack and interviewed him for soldersmoke: 


But I have one small disagreement with Jack.   It has to do with the definition of "homebrew."   Jack seems to define true homebrew as "designing and building your own rig from scratch."  My problem is with the "designing" part.  By this definition, those intrepid heroes of days-gone- by who saw a schematic in QST, ripped apart some old broadcast radios, and used the parts to build a 50 watt CW transmitter with a regen receiver were not true homebrewers.   I would maintain that they were.  I agree with Jack that kit building is a bit different, and of course designing the rig yourself earns you the coveted "designer" designation.  But for me, if you start with a schematic and an article, gather the parts and build the thing yourself, that is a homebrew project and you are a homebrewer.  After all, even the designers are very often making use of standard blocks of circuitry (Colpitts oscillators,  common emitter amplifiers, power supply circuits, etc.)

I think we will have to turn to our lexicon expert Steve Silverman for a ruling.  

In any case, thanks to Bob Crane and to Jack Purdum. 




Wednesday, May 30, 2018

Hans Summers and his QCX -- G0UPL Cracks the Code on Si5351A Quadrature


Pete,  Brad WA8WDQ and I were recently e-mailing about our admiration for what Hans G0UPL has achieved with his QCX rig.   I cc'd Hans -- we got this nice and very informative e-mail.  Be sure to click on the link provided by Hans, and from there go to the link to his FDIM proceedings article.  I think that article is a real masterpiece -- there is a lot of very valuable information in there.  For a long time, getting quadrature output from the Si5351 seemed like an impossible dream.  But Hans has obviously figured out how to do this, opening the door to much better and simpler single-signal phasing receivers.   Thanks Hans!  


Hi all

Thanks for the nice feedback on the QCX and the FDIM conference proceedings a article, which I have published on QRP Labs web page along with other Dayton trip miscellany. See


My seminar presentation audio was recorded by Ham Radio Workbench podcast and they will be publishing it on 5th June.

The QCX kit has indeed been unbelievably popular, almost 5,000 kits have been sold since the launch on 21st August. It seems to have itched an itch that needed itching, in the QRP world. Sales continue to be strong and I'm currently preparing another batch of 1000 more. 

I'm very proud of my 90-degree quadrature Si5351A and it helped me towards my low cost, high performance target for QCX. Abandoning the 74AC74 saves a part, reduces cost, reduces complexity, reduces board area (and hence more cost) and even seems to provide better performance (higher unwanted sideband rejection when using the Si5351A in quadrature mode). Getting the Si5351A to do this is one of those things which look easy afterwards. But at the time, and faced with SiLabs un-useful documentation, it took an awful lot of headscratching, trial and error!

I'm not sure of the answer to the question about noise figure. Certainly radios such as QCX and the NC2030 which use the QSD architecture seem to have very high sensitivity without an RF amplifier ahead of them. This must indicate a low noise figure. 


73 Hans G0UPL 

Monday, May 28, 2018

VK2BLQ's Beautiful uBITX in a Wooden Box


Now that, my friends, is a BEAUTIFUL uBITX.  Stephen VK2BLQ put that one together.  Peter VK2TPM helped him get the KD8CEC software into his Raduino (Stephen had trouble  getting it to compile on his Raspberry Pi).  

For me there is good news and bad news here.  The bad news is that I can no longer tell people that mine is the only "wooden box" rig that they will ever work.   The good news is that I am no longer alone. 

Sunday, May 27, 2018

INTERVIEW: Four Days in May 2018 -- G0UPL Hans Summers talks to Bob Crane


Once again, our correspondent Bob Crane W8SX has gone to the Four Days in May event and has sent back some really great inteviews with those who made presentations there.  

First on the list was Hans Summers G0UPL.   Hans is a justifiably famous Homebrew Hero, and a member of the QRP Hall of Fame.   The latest of his many contributions to the hobby is his amazing QCX transceiver.  Like the BITX rigs, the QCX refutes the idea that hams need to spend kilobucks to get on the air with a decent rig.  Priced at around $50,  the QCX offers excellent performance.  And it comes with built in test gear:  the signal generator you need to align the rig COMES IN THE RIG!  FB Hans.  

I think it was Pete who noted that the price range for rigs like the QCX, the BITX, and the uBITX is in the $50 to $110 dollar range, meaning that "One hundred bucks is the new three thousand bucks."  We owe a lot gratitude to Hans and Farhan for this very positive paradigm shift. 

Listen here for Bob Crane's 2018 FDIM interview with Hans: 

http://soldersmoke.com/G0UPL-18.mp3

We all also owe a debt of gratitude to the QRP ARCI folks who did all the hard work that goes into organizing Four Days in May.  Special thanks to QRP ARCI Preston Douglas WJ2V, and to FDIM Chair Norm Schklar WA4ZXV.  FDIM is one of the most important events on the Homebrew/QRP calendar. 

More info on the QCX (and order yours) here:  https://qrp-labs.com/qcx.html

Thursday, May 24, 2018

An Epic Evening on 40 Meters


I had a good night on 40 meters last night.   The Radio Gods were obviously with me.  

First I called CQ and VP2EIH on Anguilla responded.  Nice to start with a whiff of DX.  

Then Jason W5IPA called in and said he wanted to try out his uBITX! See the pictures below.  FB!  

Then I got a call from K5WDW on Hilton Head Island -- Dexter runs Collins gear from an ocean-front shack (see above).  Check out his QRZ page.  

Then WA4PUB called in.  Dave has been on the air since 1948 and was a student of legendary ham and radio astronomer John Kraus.  Dave has directional antennas on 40 -- when he switched the pattern he went from LOUD to barely detectable.  FB.  Check out Dave's homebrew rig below. 

Finally Gary W7DO joined us.  He has a big 4 Square on 40 that also has some really impressive directional properties.  See below for a look at his 80 meter 4 Square. 

TRGH







WA$PUB
W7DO 80 meter 4 Square



Monday, May 21, 2018

BITX Night on 7277: First N6ORS and then Canadian BITX Builders

 I was about an hour late for the Eastern time zone meet-up at 7 pm local on 7277 kHz Sunday night (my wife and I watch 60 Minutes at that hour). but I figured I could work some guys if I got on at 8 pm.  Sure enough, I was called by Keith N6ORS on his MIN-X rig.  I was on my QRO DIGI-TIA.  It was great to catch up with Keith. 

Then I got a call from VE3THR.  Last year I'd talked to Tom when he was using his BITX40.  This time he was on with his uBITX.  FB.   Tom's club in Barrie, Ontario is obviously melting a lot of solder and having a lot of fun.  Here are some pictures of their rigs. 




Sunday, May 20, 2018

F5LVG's Nail Board Receiver -- Names for the Technique


Pete WB9FLW reminds us that Olivier F5LVG has LONG been using copper nails and wood boards to build amazing rigs.  See above for one magnificent example.  That, my friends, is a superhet receiver.  Inspirational! 


A few posts back we asked for nominations for the official name of this technique.   We still have to consult with Steve Silverman on this, but the nominations are: 

Armand WA1UQO (perhaps reflecting his proximity to Washingotn DC)  "Wire-Tapping" 

Gary Hinson:  "Coffin Dodging"  (sounds a bit dodgy to me). 

And the front runner so far, from Melbourne, Australia -- drum roll please: 

Peter Parker:  "NAILBOARDING."  (Peter thinks he nailed it with that one.  I tend to agree.)  
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