A Tale of Woe from Mike WU2D, PLUS: The Importance of Band Noise

It was so cool to watch master homebrewer Mike WU2D candidly describe his error (tale of woe) made while building the Simple X Super receiver.  

It was also great to see his joy in hearing the band noise.  Watch his glee as the noise jumps up when he connects the antenna.  "That's the good stuff!"  Indeed it is.  So many younger builders see noise -- all noise -- as a bug not a feature.  Mike obviously sees it as a feature:  Thunderstorms in Brazil!  The weed-whacker down the street!  Remants of the Big Bang!  Hearing this stuff lets us know that the machine we have built is alive, and is inhaling the universe.  

Thanks Mike. https://www.youtube.com/watch?v=T_Mz9HljCys

 

No Bunching Up! It is Possible to Achieve Dial Linearity (and Stability) with an LC VFO

One of the major complaints about LC VFOs is that they allegedly cause "non-linear tuning."  Essentially, this complaint claims that you will inevitably end up with your frequencies all "bunched up" at one end of the tuning range, with frequencies greatly "spread out" at the other end. BUT WE HAVE FOUND THAT THIS IS NOT NECESARILY TRUE.  With a bit of careful design work, you can avoid the dreaded "bunching up."  I have used the calculator in Bob's Electron Bunker to DESIGN VFOs that do not "bunch up" the frequencies.  

Recently, Mike WU2D built a version of the Simple X Super receiver.  It has a VFO in the 5 - 6 MHz range.  And guess what?  There is NO bunching up of frequencies. As proof, I present the tuning dial that Mike made for his completed receiver.  See above.  Note the nice linear tuning.   

So you see, success in this area is possible -- all it takes is some careful design work. 

Similar results are possible with the other major allegation about LC VFOs:  That they are inherently and irreparbly unstable.  Proponents of this theory would have you believe that only by the use of an Si5351 (or something similarly digital) is stability possible.  Again, NOT TRUE!  It is possible to make LC oscillators that are stable.  All it takes is careful design and good construction practices. 

Mike WU2D's Video on the SimpleX Super Receiver -- Part II

 Another FB video from Mike WU2D.   

But you know,  I too find myself kind of opposed to front panel on-off switches.  I power my rigs with small DC supplies.  I just turn on the supply when I want to use one of the rigs.  I don't have or need a switch on the front panel of the rig.  

I especially liked Mike's use of the gate dip meter and, of course, the Q meter.  FB OM. 

I must say I have a preference for the first version, but only because I dislike the regenerative circuit in the second version.  I do like the newer-style coils -- I have one in the BFO of the Mate for the Mighty Midget receiver.   

Thanks Mike for the sideband inversion factoid in Part 1!   The Hallas Rule -- words to live by. 

One word of caution.  I used 6U8s on my Mate for the Mighty Midget receiver.  I had good results, but WA9WFA had a lot of trouble.  We eventually concluded that the 6U8s didn't age well.  And they were quite long in the tooth.  We found (from the tube guys) that 6EA8s aged better and were a good and easy sub for the venerable (perhaps TOO venerable) 6U8s.  I switched tubes in my rig and it did seem to work better.  BTW, this is the receiver that I use to listen to the Old Military Radio Net on Saturday mornings.  

Here is the story of our switch from 6U8s to 6EA8s: 

https://soldersmoke.blogspot.com/2022/02/6ea8s-in-mate-for-mighty-midget-and.html

SimpleX Super Superhet Receiver -- A Great Video from Mike WU2D

Here is another great video (and project) from Mike WU2D.  I'm a big fan of homebrew superhets.  And wow, Mike presents a band-imaging superhet!  Two bands for (almost) the price of one!  I have FIVE homebrew dual-band band-imaging transceivers around me.  Believe me, once you have the experience needed to build an SSB transceiver, a dual-bander is the way to go.  Five bands seems like a bit too much.  But two seems to be at the sweet spot.  

I wrote to Mike reminding him to talk about the sideband inversion problem.  This rig will invert the 75 meter signals,  but this is easily resolved by just shifting the BFO frequency.  I also pointed out that many of today's builders will be detered by the need to scrounge for parts.  Where oh where is the BOM OM? 

Thanks Mike! 

Mike WU2D Does a CCC Camp POTA with 1930's Gear

FB Mike.  CW without sidetone is not for the faint of heart.  

Walter KA4KXX saw Mike on the Reverse Beacon Network. 

Mike's QSO with KN4RRQ was especially interesting.  Tom was running a 1929 breadboard-style transmitter: https://www.qrz.com/db/KN4RRQ 

Mike WU2D POTA CCC Camp Activation (21 October 2024) with 1930s-era Station -- See If You Can Contact Mike!

Frank Jones lives!  See if you can work Mike on Monday.  Let us know if you do! 

--------------------------------

Bill,

 

I’m scheduled to tour the Civilian Conservation Corps. Camp at Bear Brook State Park here in NH on Monday. This is the largest totally intact camp in the country.

I will be activating POTA with the 1930s portable Station. The POTA CCC Camp event is scheduled for Monday around 2:30 ET (if I get everything setup after the camp tour). Primary 7057 kHz Sec 7054 kHz.

 

The station is an internal battery powered, push-pull Jones Oscillator Transmitter at around 3 Watts out, and a two-tube regenerative receiver that is a period ham artifact. So, four type 30 battery tubes in total.

The antenna is a single wire feed Windom with suspended counterpoise so basically an Off Center Fed Hertz (OCFH).

 

Between the weather, running the station, logging, and doing camera work, and of course, MURPHY - this should be nuts.

1930s Regen with Transmitter – Fully Self-Contained Portable. Note Charger that is attached to top off the internal battery on transmitter. I did not buy the proscribed 25 9V Batteries and make a TX HV pack up! I used a DC-DC converter and a LiPO drone battery! The Receiver is 100% Dry Cells However.

 

73’s Mike WU2D

----------------------------

More info here: https://www.youtube.com/watch?v=N2Pdprx0ItY

And many other great videos on Mike's YouTube channel: https://www.youtube.com/@MIKROWAVE1

A Paraset and the Heathkit SG-6 Signal Generator (Video)

Mike WU2D put out this nice video (above) about whether or not he should part out his Heath SG-6 signal generator, using the parts in a Paraset construction project.  I faced a similar question years ago: 

https://soldersmoke.blogspot.com/search?q=SG-6

I just solid stated the SG-6.  I was influenced by Farhan and the drinking straws that he picked up with his kids at a McDonalds in Hyderabad. 

As with the QF-1, I say to Mike: GO FOR IT OM!  You need those parts for other projects.  Don't feel bad about the SG-6.  But keep that switched coil assembly -- it is quite useful. 

Electronic Toys and Their Influence on Us

Mike WU2D recently put out this interesting video.  I vaguely remember the springs on the Radio Shack kits -- I also remember (bitterly) not being able to get their shortwave receiver to work.   I really wanted to tune in HCJB and Radio Moscow.  This probably led me to ask Santa for a Lafayette HA-600A receiver in 1973 or so. 

An earlier influence was the little intercom kits.  I think they worked over the AC lines?   We took some of them to the beach bungalows we had in Lavallette NJ.  With them we were able to speak clearly to similar units in nearby bunalows.  Wow, that was cool. That got me interested in radio. 

Cassette tape recorders were another early influence. I still have a recording I made with a tape recorder I got for Christmas, probably in 1972.  I used this recorder to practice CW for the ham exam. 

I managed to escape the CB madness.   But I came close to falling into the groovy psycho stuff of the early 1970s.  I remember the Transcendental Meditation gizmos.  I never built one, but if I had I may have been better off with CB. 

I kind of wish I had followed the example of the Woz and Jobs by making telephone blue boxes.  This could have led me to riches.  But as Jean Shepherd used to say, young men often come to a fork in the road: one path leads to wealth, the other to ham radio flea markets.  I got on the second path.  

Thanks Mike! 

 

A Contact with my Old Azorean DSB Transceiver

I've been thinking about balanced modulators, and I wanted to see how some of my early circuits performed.  So I pulled this OLD Double Sideband rig off the shelf and fired it up. The balanced modulator -- and everything else! - worked fine,  and I soon made contact on 17 meter SSB with Gene, AB9GK. 

This was the first DSB transceiver that I ever built.  I made this out in the Azores, probably in 2000 or 2001.  Years later I had replaced the RF power amplifier with a "JBOT" (Just a Bunch of Transistors) designed by Farhan.  

Over on my YouTube channel a comment came in from my friend Jack:  

@dhakajack

"Looking inside and seeing the o-scope probe in place while the radio was on the air reminded me of neurosurgery where the patient is awake and talking while the surgeon probes different brain regions soliciting feedback. Sure, ham radio isn't neurosurgery, but it's not too far at times. Also, you already have rocket science covered."

Here is an article about my build of that first rig:

https://www.gadgeteer.us/17METER.HTM

I think the article captures well the trials and tribulations faced by new homebrewers, perhaps with the twist that comes from being out in the middle of the Atlantic ocean.  

Mike WU2D is having similar fun with his homebrew 10 meter DSB transceiver: 

https://www.youtube.com/watch?v=uZt1LTGyoHc

I was struck by how similar Mike's early QSO experiences were with mine.  We both put our DSB transmitters on the air before they made their way into real cabinets or boxes. 

Here's mine from 2001 in the Azores: 

Retro QRP Rigs of the 1960's, 70's, and 80's -- Video by Mike WU2D

It is time to put aside (again!) all of the heated ideological arguments about the power level that defines "low power."  Just sit back and enjoy this wonderful trip down QRP memory lane. 

Mike's description of the simple, single-transistor QRP transmitter was really nice.   I recently made something similar: https://soldersmoke.blogspot.com/2023/02/first-qso-with-high-school-receiver-100.html  And Mike does a nice plug for our beloved Michigan Mighty Mite.  Go CBLA! 

The modular idea:  words to live by my friends. 

40673!  TT2!  And G3RJV's PW Severn - indeed, bow your heads!

Wow, the Ten Tec Power Mite (or Might!) -- I still want one.  Same for the Argonaut -- what a great name (sounds like a "magic carpet), and with SSB to boot!  I want to join the Argonaut cult! 

I have both the HW-7 and HW-8 (the HW-8 is heading to the Dominican Republic).  This video makes me want to fire up the HW-7.  Maybe on 40.  

My 40 meter homebrew rig (Digi-Tia) has in it the filter from that old Yaesu FT-7 rig.  The filter was given to me by Steve "Snort Rosin" Smith.  https://soldersmoke.blogspot.com/2015/05/bitx-digi-tia-build-update-2-installing.html  

Thanks to Mike for including me in the credit roll at the end.  What a great group of people -- it is a real honor to be listed with those folks.