My Mate for the Mighty Midget Thermatron Receiver

A few days ago I received an e-mail from Jan PA3GSV -- Jan is working on a receiver similar to my old Mate for the Might Midget and had some questions about how I'd handled the filter portion of the circuit.  Then on Sunday, while listening to Eric's interview with Farhan on the QSO Today podcast, I got so enthused that I felt compelled to work on a homebrew receiver.   So out came the old Mate for the Mighty Midget.  I built this thing in 1997-1998.  It is described here:

http://soldersmoke.blogspot.com/search?q=Mighty+Midget

In the above  video  I was listening on 75 meters to a very congenial early morning roundtable featuring W4CH, K5KBZ and others.  I know, I know, this is the third or fourth video that I've made of this thing.   This is almost as bad as 2B-mania. Or the Michigan Mighty Mite thing.   I blame Jan.  And Eric.  And Farhan.  And Grayson.  And Lew McCoy!

Here is my e-mail exchange with Jan:

Bill:

I recently build the W1TS two tube xtal controlled transmitter, and am looking for a 80/40m companion for this that has a crystal filter.

At first, I wanted to build the “Simplex Super” and finally got hold of the 1700 kc crystals, but then they got lost in the mail…

Only part of a two box shipment arrived, with 455 kc fundamental frequency FT-241 crystals, so now I am looking for a diagram using a 455 kc IF. Jan

Jan:   In this link you will find the schematic for the receiver I built. 

 http://jvgavila.com/mmrx_3.gif

 I was not able to build the filter with the two 455 kc crystals.  I could not obtain the needed crystals.  I used two 455 kc IF transformers as described in my article.   This resulted in a very broad frequency response but it was OK and quite good for AM. 

 Last year I put in a Toyo 455 kc SSB filter, but I did not match the impedances, so the results were not good.  Your e-mail makes me want to work on this again! 

 Let me know how your receiver turns out. 

 73  Bill  N2CQR

Thanks for your reply.

It is a neat looking little receiver.

And yes, I also have a cardboard box labeled “good junk” which is filled with stuff from ham fests J

Finally it will be put to good use!

I printed the article for some evening reading this week.

It will take me some time building this receiver, as there is some metalwork and mechanics involved.

I will let you know how the receiver turns out, and I am also curious what improvements you make on yours.

 Thanks again, and I will let you know.

 73  Jan PA3GSV

Wow, Jan has the Knack!   Check out his station:

That's the W1TS rig on the left.  More pictures from Jan on his QRZ.com site.  He too uses wood cabinets!  I'm not alone!  Here's Jan, PA3GSV

 

April 1 and WireWrapRap: How to Calculate Your Score

Let's make it official:

APRIL FOOL!

Even though "more involvement in contesting" was just another part of our WireWrapRap hoax, I thought it would be appropriate to offer a scoring scheme for those who participated in our little April 1 special event.  Just answer the following questions and keep track of how many points you earn for each:

When you read the WireWrapRap April 1 blog post, how many paragraphs did you read through before you knew it was an April Fool's Day joke? (Maximum 12 points.  If you knew it was a joke as soon as you read the title, award yourself ZERO points.)

When you read the WireWrapRap April 1 blog post,  were you at any point further convinced of its authenticity by the fact that the title of the blog had been changed?  If so, award yourself 2 points.

If after reading the WireWrapRap April 1 blog post you Googled "Wire Wrap," award yourself 5 points.  Award 15 more points if you even briefly thought that this might be a nice alternative to soldering.

When you read the section about the digital modes, did you at any point question the existence of the "new" SNICKR, Oreo, and Oregano modes?   If not, award yourself 5 points.

After reading the WireWrapRap April 1 blog post, did you  -- in an effort to confirm your suspicions -- go to  the comment section to see if others had declared it an April Fool's joke?  If so, award yourself 10 points.  (Be honest here guys.  We got 41 comments on this post, a new record for the SolderSmoke blog.  For some reason a lot of people were checking the comments section.  I'm just sayin...)  

If, after reading the WireWrapRap April 1 blog post you felt anger toward the author for the way he had so selfishly and greedily abandoned the cause of analog, discrete component, Hardware Defined, axial lead electronics, award yourself 5 points.

If, when you noticed that MANY  of the comments on the April 1 blog post had been "removed by the blog administrator," you assumed they were obscene, irate, or perhaps (justified?)  threats, award yourself 15 points. (In fact they all said "APRIL FOOL!" and were removed so that they wouldn't spoil the fun for late arrivals.)  

If one of your comments was among those "removed by the blog administrator"  award yourself NEGATIVE 5 points. 

If your anger about the changes being announced to the SolderSmoke podcast led you to send a complaining or threatening e-mail (or text or tweet!),  go ahead and award yourself 10 points (and please consider enrolling in an anger management program).

If,  on the other hand, after reading the WireWrapRap April 1 blog post you actually sent us an e-mail, comment, text, or tweet congratulating us or wishing us well on the new WireWrapRap podcast, award yourself a richly deserved 25 points. And thanks for the kind wishes.

If this scoring scheme is making you angry now, award yourself 5 points and seriously consider the anger management thing.

If, after reading the WireWrapRap April 1 blog post you actually tried to find out how to get the new podcast from Soundcloud,  award yourself 25 points.

Please send me your scores.  You can put them in the comments section (and I know you know how to do this).  Or you can e-mail them to soldersmoke@yahoo.com.   Or you can text them or tweet them to us or send them to the Soundcloud (just kidding).  Don't worry, we probably won't be announcing the winner.

Possibly the Best Ham Radio Interview Ever: Farhan on "QSO Today"

Stop what you are doing.  Run -- don't walk -- to the "QSO Today" website of Eric Guth 4Z1UG.   There you will find his interview with Ashhar Farhan VU2ESE. 

There is so much great information, inspiration and wisdom in this interview.  I was so captivated by it that -- even with the availability of the pause button -- I was unable stop listening even for the time it would take to walk to the kitchen to refill my coffee cup.  But at the same time, listening to Farhan describe the joy of bringing a new receiver into operation compelled me to go over to the bench -- in mid-podcast -- to tweak a receiver that I am working on.

In this podcast you will hear about how Farhan got started in ham radio, about his Elmers about the origins of the BITX, about the Minima and the new HF-1 rig, about Farhan's spectrum analyzer project and about a new goodwill effort to send BITX circuitry to aspiring hams around the world, especially in developing countries.

Throughout you will hear Farhan speak of the importance of the book, Experimental Methods in RF Design. 

I really do think this is the best ham radio interview I have ever heard.  Congratulations and thanks to Eric and Farhan.

Here is the link:

http://www.qsotoday.com/podcasts/vu2ese

A Major Change For SolderSmoke: Introducing the WireWrapRap Podcast!

A New Direction for SolderSmoke

Introducing Our New Podcast:  “WireWrapRap”

Attentive listeners have probably noticed that for some time now the podcast has been drifting in a new direction.  Some have been concerned by this change.  I myself, as you know, have shared in many of these misgivings.   But I have become convinced that it is time for a major change in direction.  We've been doing this for more than ten years -- we are one of the oldest ham radio podcasts.  It is time for a change.

A number of people have encouraged me to make to this change.   My co-host Pete Juliano N6QW is clearly the main influence.  Pete has made me see the errors of my Ludite ways.  He taught me that it is time to put away the Dymo tape and get with it with glowing numerals.  Whenever I started getting enthused about VXOs or about Permeability Tuned Oscillators using brass screws moving through hand-wound coils, Pete was there to remind me of the beauty, simplicity, and efficiency of Arduino Microcontrollers and Si5351 chips.   Paul Darlington M0XPD contributed an element of old world legitimacy to this push for modernity. Tom Hall AK2B was another influence -- whenever I was on the verge of quitting, he’d Skype in from the Big Apple and get me back on the digital track.  And we can’t forget Farhan over in India – as soon as he started putting Arduinos and Si570s in his Minima, I knew this was really, as the kids say, “a thing.”

So anyway, it is time for a change.    I know many of you may find this shocking, so it is probably best for me to just go ahead and say it:  We are changing the name of the podcast and we are changing its focus.

n  Instead of SolderSmoke, the new name will be “WireWrapRap.”   Wire wrap is the solder-less wiring technique often used in computer circuitry.  We hope that the “Rap” thing will be especially helpful in attracting young people – especially those Maker Millennials -- to the show.  And, you know, soldering just seems so 20^th century.     

n  Instead of traditional homebrew radio, the show will be focused on Mini Computers (especially the Raspberry Pi), Software Defined Radio, Digital Signal Processing, Microcontrollers (especially the Arduino), and the use of smart phones in ham radio

n  Obviously this implies a move away from minimalist radio and QRP.  So yes, we are going maximalist and we are going QRO. And we are getting more involved in contesting (see below).  

Now I know what some of you are thinking – that this must be part of our long-standing quest for sponsorship and that this is all about money.  But that’s only part of it.  Yes, we have secured a lucrative sponsorship arrangement with a company involved in microcontrollers, small computers and smart phones that is focused on the millennial market.  But we’re really doing this for the good of our listeners. 

Don’t worry, you will find many of your favorite parts of SolderSmoke in the new show.  They will be the same, only different.   For example, instead of the “Bandsweep” segments that we used to do, now we are going to have “Codesweep”  (and it’s not about Morse).  Where we used to have SolderSmoke Mailbag, well, don’t worry -- we are going to continue to have a segment that will allow for listener input.  We going to call it “Pi Hole.”  We’ll only be accepting listener input via TEXT messages or Tweets – we are, after all, trying to be modern.  Along the same lines, we will be distributing the podcast exclusively via Soundcloud.  So get with it gentlemen! Get into the cloud!

In the new and improved podcast we want to explore the new and exciting digital modes.  We plan segments on all the new ones: PSK-99, Opera, WSPR, SNICKR, Throb, Thor, Piccolo, Oreo, Oregano,  you know, all those weird sounds you’ve been hearing near what used to be considered the CW portion of the band.  It will be such fun!  I can’t wait to decode some Oregano!

Smart phones, are, of course, the future of ham radio, and we intend to be fully into those little magic boxes.  I don’t know if you guys realize it, but all of that ugly dusty junk in your shack can be replaced by a few lines of code from the App Store.  That room you used to call “the shack” can be converted into the Yoga studio or knitting room that your wife has been longing for!  Now you can carry your station with you wherever you go and autonomously participate in contests from stations around the world.  Imagine the thrill of learning that while you were playing golf or bowling, you were also WINNING a major DX contest from a “station” in Ulan Bator. And that ALL of your reports were 59!   It’s like owning your own ham radio drone!  Congrats old man.  YOU WON! Welcome to the 21^st century! That’s the kind of operation we are going to explore on WireWrapRap!

For those of you who are worrying that we might be abandoning our microphones, have no fear my friends, Pete and I remain committed phone operators. Only now, it will be DIGITAL VOICE.   We’ll be squeezing our dulcet tones into a mere 800 Hz of bandwidth.  This way we both sound exactly the same.  Heck with this new technology everybody will sounds the same.  How cool is that!   We’ll all sound like a mix of Stephen Hawking’s synthesizer, Apple’s Siri, and MTV's Max Headroom.   The AM guys and the Enhanced SSB crew may need some time to get used to this, but c’mon fellas, it is time to get with it!  There will be no more need to tweak all those menus for “presence” and “brightness” and “mid-range.”   Heck no, we’ll all sound the same!  Progress my friends, PROGRESS!

As I said, I had my doubts about this.  But over the weekend I walked into the TV room and Elisa happened to be watching one of those “inspirational self-help” speakers on Direct TV, and you know what?  He made a lot of sense. Change IS good!  We have to EMBRACE the future!  Impossible = “I’m possible!”  Yea!  So thank you Deepak Chopra!  Thank you Pete Juliano!  And welcome --  all of you -- to the WireWrapRap!

From Wayne and Garth in San Diego: EMRFD Joy of Oscillation Part 2

Oh great and mighty masters of the SolderSmoke:

We've continued on with this project and it has been a lot of fun.

Sure, there's

THE JOY OF OSCILLATION

but we've progressed to

THE JOY OF MODULATION (added a keyed buffer)

THE JOY OF AMPLIFICATION (added driver and PA, not threatening QRO, yet)

THE JOY OF RADIATION (perhaps my favorite)
THE JOY OF RECEPTION (picked up by RBN, yeah!)
last on the list is to experience
THE JOY OF COMMUNICATION

for that, we'll try out a number of different receivers.  Cheap SW
portable.  Softrock Lite.  websdr.org.

Does one try to count all the joys?  :-)

Here's a few snaps:

0.jpg - RBN evidence
1.jpg - lashup on the lid of a tupperware container
This worked great for throwing the work in progress in a backback for
our build session meetups.
2.jpg - Fig 1.34 less output LPF.
3.jpg - The missing LPF.  THE JOY OF FILTRATION  (OK, that's taking it too far.)


4.jpg - Fig 1.35 amp with BD139 transistor.
5.jpg - "breadboard" and a front panel to hold the T/R switch.  Key
and cheap SW portable for RX.  Waiting for DX contest to end, so I
have a chance.  :-)

6.jpg - simple breadboard chassis

Our fun has certainly been cheap.  The parts cost, including PCB and 1
BNC jack, was about $13 in low quantity from Mouser (and Diz) for all
but the amp.  The amp portion was $4 in low quantity from Mouser (and
Diz), and most of that was the expensive heatsink.  The "chassis" was
just a piece of cheap 3/4" hardwood and lexan from home depot.  I
drilled and tapped the holes in the wood for the #4 screws.  (Seems to
hold quite nicely.  I thought I might have to harden the threads with
CA adhesive as is done sometimes with balsa.)

If there are any of those air variable caps left that you are meting
out to the worthy, well, like Wayne and Garth, "we are not worthy."
If you do have between 1 and 4 and find it in your heart, we'd be very
grateful.

Best regards,

Drew
kb9fko
San Diego

Renewed Hope for Divide by 2 I and Q

An anonymous reader posted this interesting message in the comments section yesterday.  Very interesting.   A potentially important tip that may help in the quest for 90 degree phase shift with divide by 2 Flip Flop circuits.  What do you guys think?   And who is that masked man?

I wanted to make a comment regarding your Frankenstein R2 Clock divider, but did not come around to do it until now and fear if I were to put it below the appropriate post, it would be so many pages away nobody sees it. Please forgive me for posting this here if my assumption is wrong. I had a play with two edge-triggered JK - Flip Flops (74HC109 & HC107) and tied the J and K to the appropriate rails to use them as T- Flip Flops. Because of one being positive, the other one being negative edge triggered, this behaves as a divide by 2 IQ clock generator. The HC107 has an inverting clock input, so as with the other design, some kind of inverter is involved. And as Bill has reported, I initially measured the Phase shift on the scope to be off. But while playing around, I realized this was a function of the signal level. I could tune the phase shift by adjusting the signal level of the driving clock! When the clock and power supply levels were almost equal, the phase shift was very close to 90° and pretty stable with frequency (tested with 1-10Mhz). Later I thought about it some more and suspect it might have to do with the exact time the inverter "flips" on different signal levels in relation to supply voltage level. Aside from the exact cause, I believe one could vary the supply voltage of the gates with the same effect on the phase shift as with varying the signal level. I hope my observation helps to somewhat make the advantages of divide by 2 IQ clock generators more accessible.  

Grayson Evans TA2ZGE on "QSO Today"

Eric 4Z1UG has a really great interview with Grayson Evans TA2ZGE.  I'm writing this as I listen.

My reactions:

I sympathized completely with his reaction to EE professors who insisted that current flows from positive to negative.  Indeed.  Let's turn those arrows in the diode and transistor symbols around!

I too stripped down a Heathkit VFO and rebuilt it from scratch.

I share Grayson's aversion to metal work.  Viva Manhattan!  

Here is the interview:

http://www.qsotoday.com/podcasts/ta2zge