SolderSmoke Podcast #229 -- G2NJ Trophy, SDR, HDR, CW! Mailbag

Soldersmoke Podcast #229 is available: 

http://soldersmoke.com/soldersmoke229.mp3

--  G2NJ Trophy is awarded to Pete Juliano, N6QW. 

 -- Get your vaccine shot as soon as you can!  

-- More from "Conquering the Electron" by Derek Cheung. 

-- Bad fire in the chip factory.  Such a shame.  Sad!  I had NOTHING to do with it.  I was home that day.  I can prove it.

 -- Bezos is not such a bad guy.  Turns out he is a space-geek.  

 -- Perseverance was the big space news.  Very cool.  

 

Pete's bench:

Raspberry Pi vs. Microcontrollers

Treedix display

Conversion of the Dentron Scout

CW rigs?

6L6 on a wooden chassis

SHAMELESS COMMERCE DIVISION-  

I NEED TO BUILD UP TIME VIEWERS VIEW MY VIDEOS: So please watch!

https://www.youtube.com/channel/UC20TcdWSSFliMhg3k2A1a5w

--  Our Patreon sponsors get an early look at our YouTube content.  So please, consider

becoming a Patreon sponsor.

--  Please continue to use the Amazon search engine on the blog page (upper right).   

Bill's bench: 

Hodgepodge:   

-- BITX40 Module.  

-- Ramseykit Amp. 

-- San Jian counter,  

-- CW using 750 Hz oscillator. 

-- RF-actuated piezo buzzer.  

-- SDR!  SDR using PC and tablet.  

-- Checking the output with SDR.  

-- Moving the carrier osc frequency.  

 Also, I put the Fish Soup 10 back on the air.  Nice contacts under 200 mw.

Up next:  A rig for 80/75 and 20 meters.  Single Conversion.  Using VFO from a Yaesu FT101 that runs 8.7 – 9.2 Mhz.   Quiz question:  What IF should I use?

MAILBAG

Mark Zelesky sent me wood tokens with power and Ohm's law formulae.  Thanks!

Scott WA9WFA Built a really nice Mate for Mighty Midget RX – getting it going!

Tryg EI7CLB found board of his George Dobbs Ladybird RX.  Rebuild it OM!

Tom WX2J – We talked about “No lids, no kids, no space cadets” nastiness.

Nick M0NTV about sideband inversion.  I like the simple rule about subtraction.

Jonathan M0JGH – Always listen to Pete.  Got married, has mixing product. Leo?

Mike AE0IH.  Dad used a BC-348 in the service. Looking for one.  FB.

Adam N0ZIB – “Silent Shep” site --- with some ham radio shows I had not seen.

Walter KA4KXX in Orlando has a similar subtraction problem with San Jian counter.

Bill N5ALO sent me a really nice KLH speaker.   I’m using it now.

Jason N2NLY – interested in building SSB transceiver.  One step at a time OM…

Trevor in Annapolis sent xcsd cartoon that really hit home. 

Farhan is doing OK in India, diligently protecting his family from the virus.  

Peter VK2EMU also doing well.

Dave AA7EE Casually killed a DC receiver in Hollywood, and disposed of the remains. 

Charlie ZL2CTM doing great things with simple SSB.  Blogpost.

Phil VK8MC in Darwin sends article on "Mend not End" battle against planned obsolescence.

Bob KY3R re my SDR adventures, asked if I’ve had a recent medical/psychiatric evaluation. 

Michael Newton Hopkins, AB5L, Author of the FMLA series

Better than anyone else ever has, Michael Hopkins, in his fictional series about Frank Jones and the Five Meter Liberation Army, captures the spirit of homebrew radio.  There is just so much of us in those articles.  I read them some 20 years ago when they first came out; reading them again recently I appreciated them even more.  

Frank was a bit of a curmudgeon:  There are jabs at the appliance operators, Hiram Percy Maxim, hamfests, SSB, the Collins collectors, the QRP movement,  and even Electric Radio magazine.  Howard Armstrong makes an appearance, as do Carl and Jerry.  It all made me want to put a five pin SAW filter on my lapel.  

As I read, I thought about what a great writer Michael was.  When I Googled him, a few of the results led me back to  my own book.  I'd forgotten that Michael was in there, but he is.  On one page he advises me how to power my Mate for the Mighty Midget receiver without using a power transformer (a very Frank Jones approach).  On another page I note that Michael had sent me a kit for the Doug DeMaw "Barbados Receiver."  Wow, that was my first Superhet.  (I also have one that was built by Dale Parfitt.)  Most of the parts were put to use in other projects.  But I still have the board (see above).  Reminded that it came from Michael, I will now have to complete the construction.

Below is a nice article about Michael that appeared in the Flying Pigs newsletter. (Click on the images for an easier read.)   

The articles can be found here: 

http://soldersmoke.blogspot.com/2021/07/summer-reading-for-homebrewers-frank.html

Michael's 2005 Obituary:

https://obits.dallasnews.com/us/obituaries/dallasmorningnews/name/michael-hopkins-obituary?pid=14406223

Thank you Michael.  VIVA EL FMLA! 

SolderSmoke Podcast #233: PIMP, Boatanchors, Novices, MMM, Heathkits, DC Receivers, Mailbag

SolderSmoke Podcast #233 is available. 

http://soldersmoke.com/soldersmoke233.mp3

Travelogue: Cape Cod. SST. Marconi Site.

The WFSRA:   The World Friendship Society of Radio Amateurs.

Pete's Bench:

The Pimp.
The NCX rig.
The Collins.
The many DC receivers built worldwide.
The parts shortages are real! Several key radios on hold. Si5351 sub.
Talk to G-QRP convention

Bill's Bench:

FT-8. Not for me. I tried it.
Novice Station Rebuild.
Globe V-10 VFO Deluxe.
Selenium rectifier removal CONTROVERSY?
Not crazy about my Novice station. Not crazy about CW. 
Mate for the Mighty Midget. Again. 
Mike W6MAB -- Detector problems LTSPICE Check
One more mod for MMM RX. Ceramic filter at 455.
Dropped screw inside tubular cap on Millen 61455 transformer. 
Talk to the Vienna Wireless Society
Thinking of a Moxon or a Hex beam.


BOOK REVIEW Chuck Penson WA7ZZE New Heathkit Book. http://wa7zze.com

Mailbag

-- New SPRAT is out! Hooray!
-- Todd K7TFC sent me copy of Shopcraft as Soulcraft. FB.
-- Dean KK4DAS building an EI9GQ 16 W amp. FB.
-- Jack NG2E Getting close on Pete's DC receiver.
-- JF1OZL's website is BACK!
-- Tony K3DY sent link to cool books. 
-- Sheldon VK2XZS thinking of building a phasing receiver.
-- Peter VK2EMU has joined the WFSRA. FB!
-- Ned KH7JJ from Honolulu spotted the Sideband Myth in the AWA video.
-- Chris M0LGX looking at the ET-2, asks about the variometer.
-- Pete Eaton Nov 64 anti HB rant in november 1964 QST. Wow.
-- Josh Lambert Hurley spreading FMLA stickers in the UK. FB
-- Stephen VE6STA getting ready to melt solder.
-- Got a great picture of Rogier PA1ZZ back on Bonaire.
-- Farhan reading the manual of Hans's new digital rig.
-- Paul G0OER wonders if FMLA getting ready to move on 5 meters.

The meaning of "CM" in the Toyo CM-455 Filter

Photo by ZS1KE

A while back I picked up (from e-bay?) a 455 kc crystal filter for use in my Lew McCoy "Mate for the Mighty Midget" receiver.  I did a quick and dirty installation.  It kind of worked, but I had it in the back of my mind that I had to work on the impedance matching to ensure minimum passband ripple.  But when I learned what the P, B, E, and G pinout designations meant (plate, B+, earth and grid), I realized that this device had been designed with tube impedances in mind, so I probably didn't have to mess around with input and output networks (as I've done with the BITX rigs).  Last week I installed it as the manufacturer intended -- it sounds great.

Today I started wondering about the passband characteristics of the device.  What do the skirts look like?  So I started Googling.  There is not much out there, but I did come across a really interesting Epson site that describes the origins of this filter, and what the CM means.  CM is for "Crystal Mechanical."   Wow, this little box combines the characteristics of  a crystal filter AND a Collins Mechanical filter:

http://www5.epsondevice.com/en/information/technical_info/qmems/story2_5.html

An excerpt:  

"While at the Electrical Communication Laboratory of NTTPC, Mr. Nakazawa had had a flash of inspiration: ‘We could develop a crystal unit with a high Q factor by using the wire mount technology I'm studying now. Then, if we can achieve the idea of a mechanical filter that mechanically joins multiple units using quartz material, we should be able to develop a compact filter that achieves both excellent filter characteristics and thermal characteristics.’ Without a pause, he quickly tackled the next development issue, which resulted in the creation of the ‘crystal mechanical filter (‘CM filter’)*5). This CM filter was manufactured by processing the quartz substrate into an ‘H’-shaped filter element and functioned by using the long thin sections on the left and right sides as resonators (Figure 1). The middle portion connecting the two sides fulfilled the role of the coupler. This was precisely the ‘mechanical filter achieved using crystal (quartz)’ that Mr. Nakazawa had envisioned.

This filter was released on the market as a 455kHz intermediate frequency (IF) filter for single-sideband (SSB) modulation in radio communications. The use of quartz material meant that not only were good filter characteristics achieved, but thermal characteristics were also excellent. As this was the first filter to offer properties of this caliber, it sold extremely well throughout the world. Furthermore, this technology received the honor of being granted the Notable Invention Award from the Science and Technology Agency."

Does anyone have the specs on these filters, and perhaps a passband graph?

Three cheers for Mr. Nakazawa!

Soldersmoke Podcast #186 Is Available -- April 1 Rap Up, Pi Talk from Pete, Collins and Raspberries, Bill's Analog RX, Visits and Hamfests, MAILBAG

SolderSmoke podcast #186 is available:

http://soldersmoke.com/soldersmoke186.mp3

-- April 1 WireWrapRap Rap-up.  Feedback from participants.

-- Bench Reports:

   - Pete talks about his Raspberry Pi SDR DSP rig.  

   - Bill talks about on his Mate for the Mighty Midget Receiver and his R2 Frankenstein.

-- A story from Pete's youth: Cruising the "Miracle Mile" with a Heathkit "Ten-er."

-- Why do we need more RF amplification (in receivers) on 20 than on 40?

-- Have you ever tuned the BFO freq in a superhet by the "sound of the noise?"  

-- A visit to Washington by Jonathan W0OX and family.

-- Bill goes to Winterfest Hamfest with Armand WA1UQO

-- Pete on the importance of balance (in life).

-- Great interviews on QSO Today: Peter Parker, Grayson Evans, and Ashhar Farhan.

-- MAILBAG:

- Paul Darlington M0XPD has a new book about life, travel, and the Dayton Hamvention.

- Michael AA1TJ QRV with a tuning fork at its 2,000th harmonic.

- Jonathan M0JGH living dangerously with homebrew QRP in Italy.

- Ben KC9DLM JoO with MMM

- Stefan DL1DF needs 3.579 MHz rock "with mojo." We have it for you OM.

The music for SolderSmoke 186 was written and performed (the bass lines) by Pete's son Tim.  Thanks Tim!

Pete also suggested that we have some rap lyrics for this music, so renaissance man that he is,  he composed some words. We are still looking for a performer.  

Yo we solder no more – its wire wrap and cables

The cables connect to the small  black box

hold on to your pants and pull up your socks

A cable goes here and a cable goes there

Turn on the switch and its Shazam all software

 

VK2BLQ's Two-Tube Regen with a SolderSmoke Dial

 

Thanks to Peter Marks VK3TPM ("a bloke with too many hobbies") for alerting us to this magnificent homebrew receiver with the especially magnificent tuning dial.   

http://blog.marxy.org/2022/03/a-two-valve-regenerative-receiver-for.html 

We have used old CDs as dials for many years.  I have one on my Q-31 Quarantine SW receiver.  But never have we seen one with SolderSmoke emblazoned on it. FB OM. 

Stephen VK2BLQ should make sure that those 6U8s haven't gone old on him.  I recently replaced the 6U8s in my Mate for the Mighty Midget with 6EA8s.  This seemed to rejuvenate the receiver.  

Also, it is shame that Stephen doesn't keep that rig at 12 volts.  250 V?  Yikes.  As I often say, you CAN hurt yourself with 12 volts, but you really have to work at it.  Not so with 250 V.   One hand behind your back Stephen! 

Thanks to Peter and Stephen. 

SSB with Just Two Tubes

Here is the two tube SSB transmitter that Pete was telling me about.  This would be a nice companion to the "Mate for the Mighty Midget" receiver that I built a long time ago.  Another Benton Harbor Lunchbox may have to be sacrificed... 


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

Reduction Redux: Searching for Some Smooth Spin

OK, here is yet another picture of my Mighty Midget's Mate receiver, this time with yet another main tuning dial. I gave up on the large reduction drive on the right -- it worked fine but was very stiff.  I cracked open a smaller version of this very common Japanese-made reduction drive, but in this smaller one I was kind of surprised to find  a Jackson Brothers drive in there.   I now had three of these beauties available -- all of them worked fine but with considerable difference in ease of turning.  I picked the one that was easiest to turn.  

I had to cut the main shaft of the beautiful Hammarlund 35 pf variable cap that I am using. This was dangerous, because of the risk of messing up the delicate bearings.   I stayed out of trouble by putting the tip of the shaft in a vise and then cutting the shaft with a small coping saw.  This prevented any force from being transferred to the bearings.  It worked. 

I was careful to try to line up the shaft and the reduction drive as closely as I could. 

I needed something to serve as the tuning indicator.  I used one of those small CDs that often carry the drivers for cheap electronic devices.  It fit nicely.  A standard sized CD was too big. 

The final element was the knob itself.  I had an old Drake 2-B knob in my junk box (who sent me that?).  It was perfect and added a nice touch of soul to this old-new machine.

I built this receiver in 1998 and when I finished it I thought it was pretty good.  But it is much better now.  It has a nice 455 kc Toyo Crystal-Mechanical filter.  The tuning ranges on 40 and 75 now line up perfectly with the phone bands.  It now has a fuse in the power supply. And the tuning is now SMOOTH.

   

SolderSmoke Podcast 187: 2nd Anniversary N6QW. Dayton. Bench Reports. Mailbag

SolderSmoke Podcast #187 is available:

http://soldersmoke.com/soldersmoke187.mp3

Second Anniversary of Pete Juliano's arrival on the SolderSmoke Podcast.

Dayton and FDIM underway

Bench Reports:
Pete:
-- Repurposing old Circuitry
-- Pete's small Display
-- New Transmitter
-- LBS in Japan and at Dayton

Bill:
-- S38-E   The lipstick has worn off.
-- Reduction drive for the Mighty Midget's Mate
-- Back to the Barbados Barebones Receiver:
    Which LO to use for 40 Meters with a 5 MHz IF? 
    Sideband Inversion and "Lower Sideband" filters.
    Eradicating WWV with parts from AA1TJ
    Improving VFO stability
    A bandspread/bandset arrangement with fixed caps
    Soul in the Old Machine

"The Amateur is FRIENDLY..."

MAILBAG

Radio Items Picked-up at VWS Winterfest 2024 Hamfest

As always, click on image for a better view

Above you can see what I picked up at the Vienna Wireless Society's 2024 Winterfest Hamfest. 

-- On the left in the blue box is an MXM Industries SuperRX/TX 40 transceiver. It is a kit from a Texas company.   Superhet receiver with IF at 455 kHz.  Crystal controlled CW transmitter on 7040 kHz.  The oscillator works, but so far no receive signals.  I will have to troubleshoot.  Does anyone have a schematic? 

-- Behind the MXM there is a nice box marked "Diode Detector" I opened it up and there is just a solid state diode and a 50 ohm resistor to ground.   Box may be useful. 

-- I got a couple of books: "Weekend Projects" 1979 from ARRL, and "A History of QST -- Volume 1 Amateur Radio Technology 1915 - 2013" 2013 from ARRL. 

-- On top of the Weekend Projects book you see a "Crystal Holder" from Gross Radio of New York City.  W1UJR has some good history on this company:  https://w1ujr.com/written-word/gross-radio-company-circa-1931/  This device seem to be intended to hold in place a raw piece of quartz!  Cool. 

-- To the right of the books there is a serious-looking VFO.  One dollar!  Deal!  It is a CB VFO, but the markings say it puts out 5.44 to 5.99 MHz.  So it should be useful.  The dual speed dial is very nice.  

-- Above the VFO is a nice step attenuator from the "Arrow Antenna" company of Loveland Colorado. 

-- Further to the right are some Electric Radio and Antique Wireless Association magazines that Armand WA1UQO gave me.  Really nice.  The AWA mags have a very thoughtful piece (warts and all) on Jean Shepherd.  And the ER pile has an article by Scott WA9WFA that mentions my work on the Mate for the Mighty Midget receiver.  Thanks again Armand! 

-- I also got some ADE6+ surface mount mixers.  The price was right! 

Thanks to VWS for putting on this great hamfest! 

Nate KA1MUQ's Amazing Thermatron Receiver

https://natesbasement123.blogspot.com/2024/02/thank-you-bill-dean-grayson-pete-and.html

Wow, some really wonderful work is taking place in Nate KA1MUQ's basement in California. 

-- I really like the pill bottle coil forms.  I wonder if Nate faced suspicion (and possible arrest) in the pharmacy when he asked for the pill bottles.  (I got some suspicious looks when I went I asked for empty pill bottles while building my thermatron Mate for the Mighty Midget receiver back in 1998.) 

-- The variable capacitors are also quite cool, as is the big rotary switch.   Is that for band switching? 

-- Oh  man, all on a plywood board.  Frank Jones would approve!  

-- Indeed Nate, that beautiful receiver NEEDS an analog VFO.  And we need to hear it inhaling phone sigs, not that FT8 stuff. 

-- Please keep us posted on your progress.  And of course, one hand behind your back OM.  Lots of high voltage on those thermatrons.  

Thanks Nate!  

Radio History Question: Why 455 kHz as the IF frequency?

My work on the S-38Es, on the HRO-dial receiver, on the Mate for the Mighty Midget,  and on various mechanical filters has caused me to think (once again) about why we ended up with 455 kHz as the  IF frequency for so many radios.  I've heard many explanations for this, but unfortunately I've forgotten the explanations and lost the sources.  I started digging into this again today.  I found the below e-mail from Al N3FRQ on the Boatanchors mailing list (2008). 

I contacted Al to find out if he had learned anything else on this topic.  He has not.  So if anyone out there has answers to Al's questions, or anyother info that would shed light on why they went with 455, please let us know. 

------------------------------- 

Every so often the question comes up: Why are all the IF’s 455 KHz? I’d 
like to get an article together that solves this riddle while the people 
who know are still with us. I know parts of the story, but I need help 
with a couple of issues.

There are two major consideration is the choice of the intermediate 
frequency used in a superheterodyne receiver. The lower the frequency, 
the easier it is to attain high selectivity. Also, in the early days, 
before tetrode and pentode tubes, it was easier to achieve a high degree 
of amplification at lower frequencies. Conversely, a higher IF frequency 
results in better image rejection.

Early superhets had the IF at 100KHz or lower in order to get adequate 
gain from the available triode tubes. They suffer severely from 
“two-spot tuning” (images). By the early 1930’s, broadcast set had 
settled in at 175KHz, and automobile receivers would later adopt 262KHz 
as a standard.

The advent of the short-wave craze, and multi-band broadcast receivers 
dictated a higher IF frequency to achieve adequate image suppression on 
the short-wave bands. The broadcast band occupied 550-1500KHz at this 
time, and the designer encounters sever problems if his radio tunes 
across it’s own IF. Some shortwave sets used 1600-1700KHz for better 
image rejection, but one couldn’t go higher if the 160-meter ham band 
(1800-2000KHZ) was to be covered. Most multi-band receiver settled in 
near 450KHz, a comfortable distance from the first broadcast channel at 
550KHz.

Questions:

Odd multiples of 5KHz, 455, 465, etc., were usually chosen so that the 
image of the carrier of a broadcast-band station could be zero-beat with 
the carrier of the station being tuned to achieve minimal interference. 
(This assumes 10KHz channel spacing. Did the Europeans (9KHz) do 
something else?)

The Radiotron Designers Handbook, Third Edition, p. 159, states “A 
frequency of 455 Kc/s is receiving universal acceptance as a standard 
frequency, and efforts are being made to maintain this frequency free 
from radio interference.”

(1) Do FCC and international frequency allocations reflect this?

(2) I’ve heard the term “Clear-Channel IF.” Can anyone cite references?

(3) At lease one news group posting claims that broadcast frequencies in 
a particular market are assigned to prevent strong inter-modulation 
products from falling near 455KHz. Is this factual? Need reference.”

(4) Was this (3) at least part of the reason for “Radio Moving Day” in 
1941? See: http://www.dcmemories.com/RadioMovingDay/032341WINXFreqChange.jpg

(5) Many National Radio sets used a 456KHz IF’s and I think I remember a 
437 somewhere. Why? Are there different considerations for short-wave CW 
operation?

Further input, corrections, and elaborations are greatly appreciated. 
Scolarly reference will be looked upon with great favor.

Regards,
Al

-- 
Al Klase - N3FRQ 
Flemington, NJ 
http://www.skywaves.ar88.net/

SolderSmoke Podcast #191 RIGS! REAL RIGS!, BITX40 Module, EMRFD, MAILBAG

SolderSmoke Podcast #191 is available:

http://soldersmoke.com/soldersmoke191.mp3

TRAVELOGUE AND FAMILY DOINGS:   Pete son's wedding, Billy's Birthday, Gonzalo safely home in the Dominican Republic, MORE BEARS IN THE SHENANDOAH WOODS

BIG NEWS:  EMRFD LIVES ON!   Three cheers for Wes and for Tom Gallagher of the ARRL.

BENCH REPORTS:

PETE:   FPM Rig.  Some Halli history.  A TRUE RIG!  Working Japan. 

             WITH 600 WATT LINEAR AMPLIFIER!!!!!!!!!!!!!!!!!!!!!!

               New FEELTECH  Sig Gen.  

BILL: Farhan's BITX Module

           Built to Mod, built to get you started in homebrew

           Very impressive.  BITX in miniature.  But completely recognizable.

           REMARKABLY stable.

           Farhan personally checking each one.

           Ladies collective doing toroids.  DONATION money bought them some Diwali candies!

           VFO Drift:  Will NP0 SMD caps and lower current help enough?

           My Analog VFO -- BANDSWEEP

QRPppppppppppp  with REX's Hamfest Buddy.   Thanks Rex and Bob Crane.

HB2HB with KW4KD

MAILBAG

Jan's Netherland Mate Mighty Midget

Charlie's Kiwi DSB

Steve, Donald Fagan, and Jean Shepherd

Rob VK5RC repairs Tek Tube 'scopes

Colin M1BUU Si5351 superhet

Denis Klipa and NRL 3538

Jonathan M0JGH Wizard of Wimbledon Matchbox rig

JH8SST Simpleceiver

Peter Parker Vk3YE Reviews Book

Peter GW4ZUA Welsh LBS

Michael Rainey helping hobbyist in Germany with tuning forks.

A New Jersey Battalion for the CBLA? The NJQRP SNAP on 3.579

Back in 2000, the NJQRP club came up with a nice little transmitter called the SNAP. It was designed by Chuck Adams K7QO.   Dave K5YFO alerted us to it and suggested it as an alternative to the Mighty Midget.  One advantage over the MMM is that the SNAP needs no variable capacitor.  But it does need a couple of coils wound on toroids.   The SNAP design includes a low pass filter, something that has to be added on to the MMM.  Check it out.   Even if you've already built the MMM, you could easily take the crystal and use it in a SNAP build.  

More info on the SNAP here: 

http://www.njqrp.org/atlanticon/atlanticon%202000/snap.html 

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

Update on the PA3GSV M4MMRX -- And a Mystery

Note the establishment of a new acronym (M4MMRX) for Lew McCoy's Mate for the Mighty Midget receiver.  We  have needed this acronym for a long time, and SolderSmoke HQ is proud to have come up with it.  We do our part my friends.

Jan has made more progress on his amazing Dutch M4MMRX and has produced a short video showing the receiver in action with SSB and CW signals. 

Here is a bit of intriguing homebrew mystery:  Jan has gone to a LOT of trouble to create that semi-circular opening in the center of the front panel.  He even cut a corresponding semi-circular hole in the sewer pipe cap that serves as the large wheel in his amazing homebrew reduction drive.  But he won't tell us what he plans to do with that space.  So I ask you, dear SolderSmoke readers:  What is that space for?  Why the see-through panel and sewer-pipe cap?  What is Jan's plan? 

From Jan:

Hi Bill,

 The rattle is gone, so I made a little video of the MMMRX in ssb and cw mode.

 https://www.youtube.com/watch?v=Ye6myxY11LA

In the text, a ch327 and a ch45 crystal is mentioned, but I can’t get this to work.

The ch45 has a 453.6 kHz fundamental, for ch327 can’t find one.

The ch327 is a FT-243 one, tested several, but no fundamental somewhere around 455 kHz.

For ssb there is a ch45 and a ch46 crystal in, which should provide a bandwidth of about 2kHz.

(Still not totally in the clear how this should work with the very narrow resonance response of the crystals.

One should expect two peaks and nothing in the middle?)

For cw I found two ch45 crystals about 130 Hz difference in frequency, which seems to work well.

Still need to correct the 40m oscillator coil, then move on to finishing the receiver.

This is my first home brew tube superhet.

The project isn’t finished yet, but it sure is fun to build, and learned a lot during the process.

73  Jan

SolderSmoke Podcast #209 SKN, Old Rigs, Movie Review, Safety Tips, Mail Bag

SolderSmoke Podcast #209 is Available: 

13 January 2019

http://soldersmoke.com/soldersmoke209.mp3

An HT-37 "With Presence!"  Even on CW!  A Straight Key Night Story
Saving a much-loved HT-37 
Drake 2-B Alignment
Tweaking the Mate for the Mighty Midget
Fixing a Deaf DC Receiver
A Wobbly National HRO-ish Gear Box 
Minimum Discernible Signal Tests
Pete's Festive Holiday Transceiver in a Bottle

Movie Review:  "First Man"  Neil Armstrong goes to the moon. 

Safety Tips for 2019:  Fuses, Hard Drives, Flu Shots. 

MAILBAG: 
Dave G6AJW builds Pete's Sudden Transceiver
Rogier KJ6ETL builds a new shack
Steve N8NM Helps save the HT-37
Jim AL7RV W8NSA builds Parasets
Dave AA7EE puts a beacon on the air -- Please Listen! 
Jan OM2ATC builds and documents an Si5351 VFO
Bruce KC1FSZ Homebrew's a BITX
KB1GMX's Tip on IRF-510 Oscillation Prevention
Ryan W7RLF Homebrews a DC Receiver

Listening to August K5HCT from the East and West Coasts on 40
Tim WA1HLR rebuilding his 1968 transmitter.  

Mighty Midget RX on a Key Chain

The key chain device will soon be carried to 1200 feet by our new rocket.

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

SolderSmoke Podcast #164 Ancient Tribal Knowledge: Tube and Tube-like Radios

SolderSmoke Podcast #164 is available:

August 16, 2014

http://soldersmoke.com/soldersmoke164.mp3

ANCIENT TRIBAL KNOWLEDGE -- TUBE AND TUBE-LIKE RADIOS

Workbench Updates: 
-- Pete's Arduino Keyer Project
-- Bill Builds (and LIKES!)  a REGENERATIVE RECEIVER
-- The Joys of Regen Shortwave Listening
-- Grayson Evan's Tube (Thermatron) Book
-- Book review:  "The Joy of X"  (It's about math).
-- Shameless Commerce:   A Plug for Bill's Book
-- Pete discusses tube projects
-- Making your own enclosures from Home Depot flashing
-- Amplitude Modulation
-- Compactrons, Nuvistors and other unusual tubes
-- BANDSWEEP:   Radio Havana on Bill's new regen 


Bill's Mate for the Mighty Midget Receiver
3 6U8 Tubes on a Benton Harbor Lunch Box Chassis


Nuvistor 2 meter down converter


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

KG7TR's Magnificent 75S-2B Receiver -- Tubes, an Si5351, an Arduino, a Bit of Collins, and a Bit of a Drake 2-B

 

Oh man, I share this with much trepidation because the last time I posted something about the work of Mike KG7TR,  Pete N6QW said he felt like putting all of his own work in the dumpster, so much better was the artistry of KG7TR.  This receiver is so cool and so well-done that we now  might have to post a guard outside the N6QW shack -- heck Mike even has an Arduino Uno and an Si5351 in there!  Don't do it Pete!

I was led to this magnificent receiver by the very humble 6U8 tube.  Scott  WA9WFA and I have been learning (mostly from Grayson KJ7UM) that the much used and sometimes loved 6U8s (three of them in our "Mates for the Mighty Midget")  might be a bit long in the tooth, old even by Thermatron standards.  I was worried when I remembered that my Drake 2-B has a 6U8 in it -- V2, the first mixer.   So I Googled for more info and was led to this amazing receiver, a 2018 creation by KG7TR.  How did we NOT see this for almost four years?

Here is more info and pictures: 

http://www.kg7tr.com/75s-2b-receiver.html

Here is Mike's write-up of the project: 

http://nebula.wsimg.com/c2281e9bdf3b54da42ca4b0b541b4ec9?AccessKeyId=D18ED10DA019A4588B7B&disposition=0&alloworigin=1

Mike KG7TR's web site:

http://www.kg7tr.com/ 

As for the 6U8s, well Grayson says the tube has been getting something of a bum rap.  And  KG7TR has two of them in this receiver, so I will obviously have to give the 6U8 another chance.  

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

I didn't know that Lew McCoy had his own crystal and crystal filter company: 

http://www.kg7tr.com/the-real-mccoy.html

Glowbug Christmas

My "Mate for the Mighty Midget" receiver (with 6U8s)

Some excellent Christmas verse from Brad, AA1IP:

The Glowbugs' Christmas
******************************

T'was the night before Christmas
And all through the shack
Not a heater was glowing
In all of the rack.

Sitting totally silent and quiet that night
The old HRO shed nary a light.
The Johnson exciter and its homebrew final
Felt cold as leftovers, or seat-cover vinyl,

I drowsed at my workbench feeling tired and weary,
The print in the Handbook looked fuzzy and smeary.
I thought, "I'll make coffee", and groaned to my feet
When I heard a loud clatter outside in the street.

What the--? I wondered and turned on the lights
And there I beheld a wondrous sight:
A battered old van heaped high with components
And a grizzled old ham with a bagful of doughnuts.

I noted his callsign-- can't recall it today--
But a patch on the side read "FMLA".
I opened the door and hollered "Come in!
The coffee pot's heating, and we'll sit down and chin!"

He spoke not a word but whistled in Morse
A "GE OM", and "By golly, I'm hoarse.
Too many contacts, and hot rosin smoke."
I nodded and poured him a mug of jamoke.

He emptied the doughnuts in a pile on a plate
And explained in a whistle, "I'm running real late.
I've new 6L6s and fine 211s, 6146s and good 'SN7s.
And 866s and 0B2s, type 45s and mil-spec 807s."

"For the regennie crowd, 201s by the score
And good ol' type 30s and 19s galore.
I haven't neglected the passive-parts run
There's lots of good iron by old Thordarson."

I nodded and smiled, suppressing a chortle
As he reached in his pack and left me a 304TL.
He whistled, "I'm leaving, the coffee was great,
But I'm overdue in the neighboring state."

"Keep everyone building the rigs of their choosing
Or we'll lose the bands that we're lazy in using.
Transistors or tubes-- any project is fine--
Just keep on constructing and sharing on line."

He leaped to his feet and waved a gloved hand
As he sprang for the door and his rusty old van.
I heard him exclaim as he drove away from me,
"Merry Christmas, you Glowbugs, and to all 73!"

****************************

(With apologies to Clement Clarke Moore, who surely would have
been a ham had radio existed in his time. Alas, all he had
to build with was words.)

For new readers: the FMLA (Five Meter Liberation Army) appeared in a
series of short stories written by Michael N. Hopkins, AB5L (sk). If you have never
read these, you're in for a fun evening!

For QRP fans: the numerical references in the poem are for classic
vacuum tubes, several of which operate at QRP levels (whether or not that was the
original builder's intention) and (mostly) within the amateur bands.