Junk Box Ethics -- I Plead Guilty! (video)

I cringed when, at about the 32 minute mark,  during a discussion of the moral necessity of preserving old gear, Michael appeared on the screen with a Heathkit Q multiplier sitting right there next to him.  It was as if he was talking about me.  I felt as if I had been hauled into Ham Radio Court, Judge Michael Murphy presiding. 

I have already REPEATEDLY admitted to sacrificing MULTIPLE Q MULTIPLIERS.  But I did it for good reasons:  

1)  I have some objections to use of regeneration, especially in superhet receivers.  After all, Armstrong created the superhet in part to free us from the tyranny of regeneration (that he had also invented).  

2)  This is a case where the parts ARE greater than the sum.  Specifically that variable cap WITH reduction drive.  And that perfectly sized metal box. Those capacitors are currently in service in at least two of my homebrew SSB transmitters. And as I look around the shack, I see one of those boxes housing an Si5351 VFO, and another holding the dual-digital frequency displays for my DX-100/HQ-100 AM station.    

3)  Mike notes that these Q-multipliers are being sold for TWO DOLLARS at hamfests.  At prices like this, temptation is just too strong. 

So I plead guilty, your honor.  But I ask the court to consider the circumstances under which I dismantled this obsolete gear, and the good uses that I made of the parts that I obtained.  Also, I'd like to make note of the fact that I salvaged from a junk pile a Heath VF-1 (I completely rebuilt it) AND I restored to usefulness a Heath DX-40 -- both these devices appeared in the WU2D video.  Finally, if anyone really needs the remaining parts from the now deceased QF-1s, I'd be willing to donate them (in an effort to redeem myself). 

Thanks Mike!  

How to Generate an AM Signal (and DSB!) in LTSpice

Pretty cool and very useful.   You can also do this by using the Modulator symbol, but I found this technique easier and more straightforward. 

But be sure to watch all the way to the end of the video.  Early on, he forgets the step that causes the carrier to stay in the simulation, but then shows how to correct this.  In the process we learn how to create a DSB (suppressed carrier)  signal in LTSpice. 

Lebanon's First Radio Website

I found this site through Paul VK3HN.  He took the AM detector circuit for his AM receiver from one these Lebanese homebrew radios.  

There is some really great information on this wonderful website.  It has been online for some 20 years -- I wish I had found it earlier.  The author shares his Knack story -- this is a wonderful example of the International Brotherhood of Electronic Wizards (IBEW). 

http://www.midcenturyradios.com/index.html

And he has very cool schematics, really well done.  Click on image to enlarge: 

Wild Woody WARC Keys

From the NAQCC newsletter: "The key is Dave's own unique invention called the WILD WOODY WARC KEY, and each key is consecutively serial numbered. (My key is number 476). WILD WOODY WARC KEYs have a place of honor in the ARRL Headquarters, and in the offices of Kewnwood, Icom and other such places. Dave, as some of you may know writes a monthy column for CQ Magazine and is the author of several books on keys, QRP operation and other subjects. The WILD WOODY WARC KEY is pictured below. Ingenous simplicity -- a true work of wonder. Thank you Dave."

I post this for several reasons.  

1) A friend recently complained that telegraph keys are getting expensive.  "Ha!" I said.  This proves me right.   Clothes pins are not expensive. 

2) I think we should make more use of clothes pins in ham radio.  They were used in my 20/15 meter dipole in the Dominican Republic. 

3) I worked K4TWJ several times -- twice from the Dominican Republic, and once from Virginia using a homebrew transceiver that he had inspired.  He was pleased.  It was cool. 

4) As a little kid, I liked Woody the Woodpecker. 

4) On Thursday morning my wife and I saw a Pileated Woodpecker (just like Woody!) in our neighborhood.  TRGHS. 

Mr. Carlson's Lab Attacked by Dangerous Canadian Snow Static! (Video)

Even when describing something as simple and basic as snow, Mr. Carlson is electronically awesome.   This video made me realize that in the event of an EMP, his will probably be the only lab to survive.

The SolderSmoke Daily News took up the topic of snow static back in 2011.  Be sure to read the comments, especially the one from KC7IT about the QUARTER INCH ARCS that woke him up in the dorm at MIT.  Check it out: 

https://soldersmoke.blogspot.com/2011/10/snow-static.html#comment-form

I've got to get one of Mr. Carlson's 2020 calendars! 

  

Hack-A-Day and Copper Tape

https://hackaday.com/2020/01/15/the-flexible-permanence-of-copper-tape-circuits/

and

https://halestrom.net/darksleep/blog/039_coppertape/

The End Fed Half Wave Antenna and EFHW Tuners

In the SPRAT 179 (Summer 2019) article describing their Peregrino (Pilgrim) transceiver,  Joan EA3FXF and Eduardo EA3GHS recommend the use of an End Fed Half Wave (EFHW) antenna. Their circuit incorporates an EFHW tuner and an SWR indicator.  As I planned my trip to the Dominican Republic with a uBITX, I had this antenna system idea in mind.  I was attracted by the possibility of avoiding having to carry coax with me.  And it seemed that an EFHW antenna would be easier to get up in the air than a coax-fed dipole. 

When searching for schematics for EFHW tuners I came across the QRPguys tuner kits.   

https://qrpguys.com/end-fed-half-wave-sota-antenna-tuner

This looked like just what I needed, so I ordered one.  But I placed my order kind of late, and I started to worry that I might not get the tuner kit in time.  So I decided to homebrew my own (just in case!) 

As it turned out, QRPguys got the kit to me in plenty of time. It went together very quickly and is a really useful piece of gear.  My homebrew version works fine, but I prefer the QRPguys device. 

You can check out the manual here: 

https://qrpguys.com/wp-content/uploads/2019/09/efhw_40m_tuner_assy_090119.pdf

The circuits are interesting.  The EFHW antennas present an impedance not of 50-70 ohms, but of 3000-5000 ohms.   The Peregrino and the the QRPguys circuits use a matching transformer to change the high impedance to 50 ohms.  In both circuits polivaricon capacitors are used to tune for resonance. The QRPguys circuit uses an N7VE LED absorption bridge -- I found it very satisfying to put the circuit into "tune" mode and then just adjust the capacitor until the LED went out.  That means the antenna system is presenting 50 ohms to the transmitter. 

SOTA beams has a good explanation of the EFHW antenna here: http://sotabeams.co.uk/efhw/
I did use a counterpoise. 

The Experimenter

https://www.americanradiohistory.com/The_Experimenterr.htm?fbclid=IwAR2k7bmbXoRXg6rTiy411riH1WfWUvqso1lpGEn8cEEGk2JKb8FKB4OT7zo

I think I have a set of those headphones. 

Thanks to the K9YA Telegraph for alerting us to this.   

Mike WU2D on QSO Today with Eric Guth 4Z1UG

Eric Guth has a great interview with homebrew and boatanchor guru Mike WU2D.  

Listen here: 

https://www.qsotoday.com/podcasts/WU2D

Wow: "My receiver was from a Sherman tank." 

His story about getting in trouble after "borrowing" his friend's callsign was really great. 

I also liked his wise comment about how anyone who homebrews simple gear will collect some "wallpaper" from official observers and the FCC.   Mike is right:  we shouldn't get too concerned about minor transgressions. If we do, we run the risk of becoming so careful, cautious, and fearful that we never BUILD anything.  

There is a wonderful discussion of the Paraset. 

Mike coins a term that we might want to add to the SolderSmoke lexicon:  RetroQRP.  (Over to you Steve Silverman.  Your call OM.) 

Notes From the Dominican Republic on possible uBITX mods

It was really great to have the multiband and CW/SSB capabilities of the uBITX with me in the Dominican Republic.  And even with my large wooden box, the rig and all its accouterments fit into my carry on baggage (and there were no problems with airport security). (In the picture above you can see the cloth case that held the whole station, including the antenna.)  

As I used the rig, I thought about possible mods for future operations.   Here are some ideas: 

-- Filter for CW?  Definitely.  Farhan suggested switching in a more narrow 12 MHz IF filter for CW operations, but that seems like a bit too much work.  I am going to try to use an audio frequency filter.  I've ordered the active CW filter from QRPguys.  I've long been intrigued by these kinds of filters, but they didn't seem very wirthwhile with a DC receiver.  With a superhet like the uBITX they make a whole lot more sense. 

-- Sidetone volume control.   Need it, especially with fellow vacationers trying to sleep nearby.  Should be easy -- just a pot on the side-tone line.

-- Low impedance mono headphones.  Need them.  

-- An LED light for logging.  Would help. 

-- Switch to turn off the 16X2 display to save power?  I thought about this but I checked after we got back and the whole display pulls only about 20 ma.   So it probably isn't worth it to put in a switch. 

-- Internal protective cover for the uBITX board.    I used the extra space in my big wooden box to store the key, the mic, the battery, the tuner, etc.    They all bounce around a bit and could damage the uBITX board.  So I will try to build in some internal physical shielding, perhaps from a BITX plastic box. 

-- Brass contacts for my homebrew CW key.   I think brass is better than the copper foil I am currently using.  I already did this with some brass bolts from the local hardware store.  Mush improved.  Pounding brass is better than pounding copper tape. 

-- I installed an additional stage of microphone amplification but I have this stage running even on receive.  But I checked and the amount of current pulled by this stag is so small that it is not even worth changing the power supply line. 

--  Reduce output to below 5 watts on CW.   To make the rig "QRP Compliant."  

In the pictures you can also see my homebrew straight key, the QRPguys EFHW tuner, my mic (the original SolderSmoke podcast mic!), the 3 amp-hour LiPo battery, the additional stage of mic amplification.   The little relay that you see just above the mic amp allows for the keying of an external amplifier.