FDIM Midnight Mojo Ceremony (Tuna Tin 2)

Tyson Tuna Tin Two

An important message From Rex, 
Transcendental Titan of the Tuna Tin Twos:

 --------------------

Fans of the Ancient Sacred Relic,

If you have a little QRP rebel in you, like me, and are a fan of Ancient Sacred Relic, i.e. The Original Tuna Tin 2 transmitter, and all things housed in round metal containers usually designed for fish products and pineapple, and maybe cats if VERY thoroughly cleaned, then you might want to bring your Tuna Tin 2 rig to FDIM!

Around midnight, after the scrum leaves the FDIM Club night gathering, there will be a Tuna Tin 2 Midnight MOJO ceremony! THE one and only ORIGINAL Tuna Tin 2 transmitter will be on hand for this solemn occasion where major QRP MOJO is transferred from the Ancient Sacred Relic into the tuna can inductees in attendance. Admission is free but you MUST bring a MOJOee tuna can housed rig for entrance to the ritual.

NO rectangular or mint tin equipment will be admitted!! NO unaccompanied minors OR adults OR adults who act like minors will be admitted.

TT2 QRP MOJO will be transferred....FUN will be had.....PRIZES will be raffled off!

If you think you might like to be there for the Tuna Tin 2 Midnight MOJO ceremony remember to pack a tuna can or reasonable facimile (307 (3 + 07/16" diameter) industry standard 2 piece or 3 piece can) housed TT2 style rig in your travel bag!!

REMEMBER: NO rectangular or mint tin equipment will be admitted!! You must have a TT2 inspired rig in you personal possession to gain
admittance! NO exceptions!!

Respectfully submitted,
Rex  W1REX  The TUNA Tinman!
--------------------

 

I will not be at Dayton, but I might be able to lend my TT2 (seen above with Tyson) should some worthy radio amateur wish to participate in the midnight ritual.  Time is short, so if you are interested,  send me an e-mail explaining why you are worthy. 

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

I Too Built a Tuna Tin 2

I didn't plan on doing this.  I didn't even really want to do this.   I've become a phone guy -- I'm not into CW anymore.  I figured I'd just finish the Herring Aid 5 receiver and settle the score from 1976 and that would be it.  But everything I read about the Herring Aid 5 included references to the iconic Tuna Tin 2.  Obviously I was also under the strong influence of my late February encounter with the original TT2 at the Vienna Wireless Winterfest.  That Mojo is powerful stuff!   Then my wife brought home this can of Russian tuna.  The dimensions were perfect.  Then I looked in my junkbox and found 40 meter CW crystals.  That was it. I had to do it. 

I built mine Manhattan style, using several of W1REX's fantastic Me-pads.   I also used as the final a transistor that Rex gave me at Winterfest. Thanks Rex.  Soul in the New Machine. 

I'm getting about 200 mW out.  I;m on 7030 kHz and 7040 kHz and 7110 kHz.   I have the TT2 up with my Drake 2-B (Herring Aid 5 integration will come later).  I can feel the Mojo. 

I just had my first contact with the TT2:  I called CQ on 7110 and AB2RA came back.  Jan was running 20 watts from an old 807 rig, listening with an old Hammarlund.  So it was HB transmitter and vintage receivers on both ends!  FB!





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

The SolderSmoke Team Talks to the River City Amateur Radio Communication Society (Video)

Pete and I had a great time speaking to this really nice California ham radio club (video of the event appears above).  Special thanks to club president Dr. Carol Milano, MD.  Wow, what an impressive person and ham radio operator she is:  https://www.qsl.net/kp4md/#New%20York

This club is doing a group build of a version of the famed Tuna Tin Two.    I mentioned that I had held the original TTT in my hands, and that Rex Harper had conducted a "Mojo Transfer Ceremony" that imparted TTT Mojo to my BITX17 transceiver (which was also discussed).  I promised to share the video of that momentous event.  Here it is: https://youtu.be/9RZRaFUtTcc

Thanks to Carol and the members of the RCARCS.  This was a lot of fun.  

Ralph AB1OP -- A New Receiver (with Mojo) and A New Acronym (with Attitude)

Bill and Pete,

😀 Completed the wiring the LBS Part I (pics attached)

I've said wiring completed but, it's not really done. lt will need some peakin' & tweakin' and I already have made design changes to the power board. 

My Summer Project took ALL Summer, had the usual excuses with Summer activities, family obligations,  interruptions and days of just plain goldbricking. 

At last all the LBS Part I boards were laid out, etched, populated, soldered and installed.  As a novice Toroid winder it took a  while to get the toroids done. (I had to do THREE DBM Transformers to get two  to match.)

Some features of note: 

1. Extensive use of the recycle bin for front / rear panels and feet. (Tin can and bottle caps) Go Green!

2. Extra Mojo was induced with using the 10K pot Farhan supplied with my first Bitx40 Kit that I did not use, (I replaced it because I could not find knobs for 4mm shafts back then)  

3. Junk box speaker (8 Ohm - 0.5 W) from a cheap radio alarm clock my Mom threw away after it stopped working.

4. Use of the RG405 coax for interstage RF connections. (No Murphy's Whiskers)

😞 My tale of woe. Apparently after connecting the LBS Part I stages together I put the AD9850 module back in it's socket upside down --- then applied power,  Awaiting the replacement. HIHI

😜 SITB or Stick-It-To-Bezos.  Again this month my Ham stuff budget was blown on an Amazon order (replacement AD9850 modules being not cheap anymore). I started at the soldersmoke blog web page search bar so there should be a little something heading to your North Virginia QTH from Jeff.

73,

AB1OP_Ralph

Waco Mighty Mite Mojo!

Eric:  Wow, great news from Waco.  JOO indeed!  And I really liked the WAY you did it, liberating crystals and wire from old TVs.   That definitely adds mojo to the Waco M^3.  Bill

 

Hello Bill,

  My name is Eric Melling KD0OXY. I have, as of tonight, officially passed selection for the CLA. My Michigan Mighty Mite began oscillating tonight between 1830 and 1900 CST and I am ecstatic about it! My foray into home brewing began mid-2011 when I obtained my general class ham license (I took Technician and General at the same time taking advice from my late grandfather). The first radio I ever purchased was the Pixie II kit and boy was that frustrating. I meticulously assembled the kit and worked very hard to stuff the transceiver, volume control, options to use the on-board key or a straight key, and maybe an on-board speaker or phones.  But, to my chagrin, I was treated to the sweet wafting smell of the magic smoke long before ever getting on the air. I eventually did get on the air with my aforementioned grandfather's VHF/UHF HT and until recently, this has been the extent of my Ham career.

 

  But on the advent of my starting an MA in applied linguistics at a school in Dallas (hour and a half from home in Waco) and the rekindling of my electronics knack occurring near- simultaneously with my discovery of the SolderSmoke Podcast, I decided to give it another go. First, I got the old pixie kit to oscillate and then ripped it apart for parts to another project (non-radio). Then I procured a second Pixie kit from ebay and built that. It oscillated right away! Still no contacts; my CW is... improving.

 

  All this to say that I still had an itch that wanted scratching Enter: The Color Burst Liberation Army! Not only could I truly build something from scratch, I could follow my true calling and de oppresso liber some crystal. So I pulled some 30 (or so) gauge magnet wire from an old CRT. I had wound and rewound my coil three times (and unfortunately, the third one looks the worst) for 80m then 20m (far fewer turns) and back to 80m with N'JOO (No Joy of Oscillation) in any configuration. I am using a polyvaricon pulled form an old AM/FM transistor radio, the Mitsumi PVC-2FX which has 82 pF, 140 pF,  20 and  40 pF sections which I have wired in parallel giving me ~0-282 pF of range? And finally, I was using a MPS A42 NPN transistor. I had to run some resistors in parallel and some caps in series to get the right values, but I eventually got it all together and looking pretty smart on a 1" x 1.5" piece of perf board. Alas! Nothing!

 

  I was poking around at the circuit and realized that when I keyed the transmitter, the coil would get really hot right at the tap. I still don't know why that was, but I figured it was a good sign as it meant something was happening. I also was getting plenty of pops and clicks on the receiver. Anyway, to make a short story long, I decided that the dark mark under the transistor was a bad sign, found an NTE 123 and plugged it in instead. And oh what a wonderful day to hear the first warblings of my very first all scratch built transmitter hitting the airwaves! And here is the video: https://youtu.be/yq2M1ryMkII

  

  Probably more than you wanted to hear, but there it is. I do plan to build an SSB transceiver someday (hoping sooner than later). I feel you and Pete and your podcast have really set me out on the right foot! I hope to HB2HB with you soon!

  Sincerely,

    Eric KD0OXY

Tuna Tin Mojo Transferred to BITX17!!!!!!

It happened at the Vienna Wireless Society's Winterfest Hamfest today in Northern Virginia.
That is Doug DeMaw's original Tuna Tin. 
This may be the first time TT Mojo has been given to a phone rig. 
Doug DeMaw would, I'm sure, approve.

Thanks Rex!


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

Listen to Rex. W1REX. Lots of Tribal Wisdom in this Ham Radio Workbench Interview

 

https://workbench.libsyn.com/hrwb-193-building-projects-with-rex-harper-w1rex

This week's Ham Radio Workbench podcast features an interview with Homebrew Hero Rex Harper, W1REX of QRPMe fame. (The bulk of Rex's portion starts at about 1:26:30.)

I really liked this talk with Rex.  His enthusiasm for homebrewing is really inspiring -- it is very reassuring to know that there are others like us. Rex clearly has The Knack.  

I got a kick out of Rex's story about the outhouse at Dayton.  FB OM.  

Here is the video of the mojo transfer ceremony in which shared some of the Tuna Tin 2's mojo with my BITX 17.  Thanks again Rex!  

And thanks to George and the gang out at Ham Radio Workbench. 

The Original Tuna Tin 2 (and the Mojo Transfer Ceremony with W1REX)

From the Amateur QRP Radio group on Facebook:‎

Brian Murrey‎to

 Amateur QRP Radio

The Original Tuna Tin II built by Doug DeMaw W1FB (SK)...Ed Hare W1RFI of the ARRL Lab, brought this to FDIM in 2001 and allowed us to borrow it for a night. It was so cool. The little guy was found at a hamfest somewhere on the east coast, and brought back to the ARRL. Bruce Muscolino W6TOY (SK) recieved it from the ARRL and he replaced missing parts and got the thing working again. It's in the museum at the ARRL HQ today. I think we made like 16 contacts using that for the transmitter, and a homebrew receiver from Diz W8DIZ that was part of the MultiPig Rig. Antenna was a dipole we had strung up out the window of the Ramada Inn (FDIM Central).
-----------------------------------
Here is my only encounter with the original Tuna Tin 2 -- In 2014 Rex W1REX conducted this solemn ceremony in which some of the TTT mojo was transferred to my homebrew BITX 17. 

An Enthusiastic Recruit for the Color-Burst Liberation Army



Hey Bill and Pete

Man, I am loving the podcast! 

It is absolutely what I need, and what ham radio needs today!!!

I am at about episode 168 trying to catch up.

I would really like to build a Mighty Mite.

In fact, going on the record,  

I AM GOING TO BUILD THE MICHIGAN MIGHTY MITE.

If you have any crystals left could you please send me one.

I've got a 9 year old boy that's home schooled and I want to make this electronics hobby a stepping stone to a higher learning experience. 

I got in to ham radio to learn electronics and somewhere along the line I just learned how to send and receive CW and how to pass multiple choice question tests. Somehow along the way I lost my love of radio. I still have a nice modern day rig, but it has no "soul". I heard that comment in one of your episodes and it really rang a bell with me and when it rang I said,

 "Oooh, that's Awesome! "

I want a radio experience with soul!

I think that maybe why folks still use CW. It's a mode with soul. I know you champion SSB, but home brewing a CW transmitter and receiver has got to be a truly soulful experience.  And its one I intend to have as one of my own.

 I too want to enjoy the "Joy of Oscillation ".

With you guys inspiring me, I am sure this will be a wonderful adventure. 

THANK YOU! THANK YOU! THANK YOU!

For your guidance and inspiring work in the field of homebrew radio.

Sincerely,

Paul Hodges

KA5WPL 

P.S.

The chemistry of you 2 guys on the show REALLY remind me of Click and Clack. You guys really work well together! 

PLEASE DON'T STOP!

73

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

Paul:  Consider yourself inducted.   There are, however, some conditions:

1) You MUST build the MMM and make it oscillate (thus experiencing the JoO).

2) You MUST send a picture or (better) a video of your MMM in operation.

3) You have to give me permission to put your e-mail (below) on the SS blog.

4) You have to send me your address so I can issue you a for-real SS 3.579 crystal (with mojo).

Deal?  73  Bill

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

Deal,

I'll do my best to get video, at the very least I'll get pics.

As for making it actually oscillate, well if the "radio gods" let it be then I'll be having some good vibrations going on in the shack. Hope to have it going before first snow...of 2015...

Also, being inspired as I am, I made a CW contact with 5 watts since I emailed you last. 

Thanks for helping me get the fun and excitement and the adventure back in to ham radio!

Sincerely,

Ka5wpl

P.S.

Please send a card if you have one with the crystal. 

PPS  Also why not initial it if you've got a small enough pen :)

73

----------

Paul's Knack Story is here: http://www.qsl.net/ka5wpl/

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 #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

 

Radio Astronomy Knack!

This video has so much of the kind of stuff that interests us:  roadkill antennas.  3D printers.  Arduinos.  Raspberry Pi, And of course, RADIO ASTRONOMY.   

And the Thought Emporium guys have a lot of other great project videos on their YouTube site:

https://www.youtube.com/channel/UCV5vCi3jPJdURZwAOO_FNfQ

I feel myself being pulled back into SPACE.  First there was Farhan's new satellite, now this.  Last weekend I finished a 3 element quad for 146 MHz.   In a fit of nostalgia I used the same copper tube elements that I used to communicate with the MIR space station from the Dominican Republic in 1995. They have good JuJu.  And Mojo.   TRGHS.  More on this later. Tune UP!  

LA6NCA Designs and Builds a Very Hybrid 80 Meter Transmitter (Si5351 and a 12A6 Tube) (Video)

Helge LA6NCA put out a really nice video explaining how he designed and built an 80 meter transmitter. 

I like how he put the Si5351 and the Arduino chip in what looks like a slightly expanded FT-241 crystal box.  Nice.  

I like the box and the chassis.  

I like his testing/tuning technique.  

The homebrew capacitor was a very nice touch.  

Where can I get some of those coil forms?  

And of course, the R-390 receiver adds a lot of mojo to the shack. 

Helge's web sites document an enormous number of great projects:  

Helge's page on the 12A6/Si5351 transmitter: https://www.la6nca.net/homebrew/tx_12a6/index.htm

Helge's main site:  http://www.laud.no/fykse/index.htm

Thank you Helge! And thanks to Hack-A-Day for alerting us to this. 

SolderSmoke Podcast #159: Hamfests, Herring Aids, and Tuna Tins

 

SolderSmoke Podcast #159 is available.

 



http://soldersmoke.com/soldersmoke159.mp3

April 1, 2014
Vienna Wireless Hamfest
BITX Talk
W1REX speaks
Tuna Tin 2 Mojo Transfer Ceremony
After 38 years -- finishing my Herring Aid 5 receiver
Feedback, Phasing Dots, Rotational Sense, and Oscillation (or not)
Motorboating (when you don't want to)
Building my Tuna Tin 2 with parts from W1REX
On the air with Tuna Tin and Herring Aid
More Minimalist Meanderings:
An (Almost) All Altoid Crystal Radio!
Tek 465 dies (again) :-(
MAILBAG

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

Help! Can You Write the Software to Control the MAX2870 Board?

 

It is not every day that you get the chance to help a master homebrewer like Pete Juliano N6QW.  But today is just such a day.   Pete asks for some coding help: 

https://n6qw.blogspot.com/2022/03/march-18-2022-help-software-programmer.html

The Radio Gods would be pleased if you help.  The Mojo and Juju levels of all your projects would increase.   If you can help, please do so.  

"That 70s Show": Steve "Snort Rosin" Smith Restores a 70's era Tuna Tin 2

Hi Bill,

Your recent stories about your TT-2 and original TT-2 "mojo transfer" prompted me to resurrect my TT-2 'resto' project. 

The attached photos show my 70s era TT-2 obtained for $5 from a QRP-L member.  This is how I received it and you can see that it's almost a duplicate copy of the original, complete with 'phenolic' substrate PC board material and hand-scrawled traces. 

I have collected most of the components necessary to convert it to a look-alike of Doug Demaw's 1976 item.  I already have 1 or 2 of the proper Radio Shack RF chokes but lack one more to have the complete set and I'm about to grab some original Radio Shack 276-1617 transistors.  The rest of the missing/incorrect parts I can drag out of the ever expansive Snort Rosin junque box. 

By hand selecting the two transistors for max. power gain I hope to eek 300 mW out of the thing.

Anyway, hope you enjoy the shots and I'll send more when it's finished.

73.......Steve Smith WB6TNL
          "Snort Rosin"

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

A Beautiful Variable Capacitor (from Pete)

Is this a thing of beauty, or what?   Pete sent this to me back when I was having trouble finding a "smooth running" variable cap for my HRO dial receiver.  It has a standard Jackson Brother's reduction drive attached to the shaft, followed by a really cool gear arrangement.  Note the spring loaded teeth on the big gear -- that is to keep the gears tight when turning in both directions.  

As was the case with the HRO dial that Armand sent me, the beauty of this part will cause me to build something with it, really just for the purpose of putting it to use. We've been talking about double or triple conversion superhets with 100 or 50 kHz final IFs.  At those frequencies you can get good selectivity with LC filters.  As with the Drake 2-B.    Steve N8NM is sending me a dial that will go well with this part.  That will add to the already abundant mojo/juju.  I feel a VFO in the works.    Thanks to Pete for being so supportive of my luddite analogism.  

YAMMM! Yet Another Michigan Mighty Mite! From KC0ZIR in Northern Virginia

Bill,

Thank you for the podcast and the loads of tribal knowledge from you and Pete! I recently started going through the SolderSmoke backlog, and I am just getting to the Colorburst Liberation Army episodes. I had some crystals for 40m laying around, so I started reading up and winding on a film canister.

Later, I thought I'd hop up the current episode of the podcast while I work, and I heard you guys talk about another push for the Michigan Mighty Mite. I happened to be salvaging bits from an recycling-pile VCR at the time, and I came across this crystal with a familiar label: 3.579545. The radio gods have spoken, so I will be winding a new coil for 80m.

I heard you mention the anonymous benefactor, but I have some aluminum foil, and I plan to brew the cap as well, there are a few options here: http://www.instructables.com/howto/variable+capacitor/

I thought I'd tell you a quick story anyway, because I just want to be a part of the fun. When I was little, our radios all had retractable antennas, and the TVs all had rabbit ears or loops. I would spend nights trying different materials and orientations to try and get better signal. At one point, I ran as much wire as I could in my brother's room (he had a big garage-sale cabinet tv), and we were getting channels from all over the place. We knew when each channel would be showing reruns of Star Trek, so we could catch an episode or two almost every day of the week. We even got some channels that I thought were only available on satellite. I had read in my box of Popular Mechanics magazines that some dish setups re-broadcast their signal on VHF/UHF frequencies with low power, I always suspected that's what we were picking up. 

I didn't know much (or really anything) about the theory behind antennas at the time. I'm still a bit hazy, like with the 75 ohm / 50 ohm cable thing. I thought resistance was a function of length, how can different lengths of coax be the same ohm rating?

Anyway, I just wanted to let you know I'm new to homebrewing, and you guys are a big part of that!

73,

Dan, KC0ZIR

Northern Virginia (a little to the left of you, it sounds like)

..............................

Excellent Dan! 

Getting the 3.579545 MHz rock out of a dead VCR definitely adds mojo to the rig.  Indeed, TRGHS! Thanks for sharing your Knack Story.   I hope to meet up to you, perhaps at the hamfests of Northern Virginia.  In my capacity as Grand Poohbah and Arbiter of Capacitor Eligibility, I hereby deem you  ELIGIBLE for a variable capacitor.   Our secret benefactor will be contacting you.  

73  Bill   

Switching to a Mechanical Filter from 1967 for my HRO-ish Receiver (with video)

From RSGB Handbook 1982

Having overcome the difficulties with the National NPW Dial and Gearbox, I turned my attention to the 455 kHz filter.  I had been using this old Toyo CM - 455 kc filter (Date stamped August 1969).  CM stands for "Crystal-Mechanical."  These filters are hybrid with some of the features of a crystal filter and some of the features of a mechanical filter. For more details go here: 
https://soldersmoke.blogspot.com/2016/04/the-meaning-of-cm-in-toyo-cm-455-filter.html

I was disappointed by the CM filter.  It seemed very lossey, and it just didn't seem to be of sufficiently high Q -- it seemed very broad. I could hear the other side of zero beat.  It was barely a "single signal" receiver,  and being "single signal" is the whole point of a superhet. 

I remembered that Pete Juliano had sent me a Japanese-made 455 kc mechanical filter. Maybe this would do better.  Last night I did a quick comparison test and -- wow -- Pete's filter was much better.  The Fifth Edition of the RSGB Handbook seems to agree with my assessment, noting that mechanical resonator filters were superior to the Crystal Mechanical hybrids (see pages 4.17 and 4.18) 

Pete's filter is from the Kokusai Electric Company.   Part# MF 455 ZL.  (Date stamped May 1967). "ZL"indicates lower sideband.   I checked and indeed the passband goes from just above 452 kc up to about 454.5 kc.  This is a 40 meter receiver and SSB on 40 is LSB, so this filter would work perfectly right?  Not so fast!  Sideband inversion had to be considered.  

I was running my VFO from about 7455 to 7755 kHz.  This means that the modulated incoming signal would be SUBTRACTED FROM the VFO signal to get to  the 455 kHZ IF.  And when that knd of subtraction happens, we have sideband inversion.  The LSB signal will look like a USB signal when it reaches the filter. 

My BFO was running right at 455 kHz, using a ceramic resonator at that frequency. I briefly considered just shifting it down to 452 kHz, but this proved to be difficult.  Then I got a better idea. 

I could just shift the VFO down to 6545 to 6845 kHz.  This would mean that the VFO frequency would be subtracted from the incoming modulated frequency.  There would be no sideband inversion.  I had been thinking about doing this frequency shift anyway, thinking that VFO stability gets better as you go lower in frequency. 

REMEMBER THE RULE:  If you are subtracting the modulated (signal) frequency from the frequency of the local oscillator or VFO, only then will you have sideband inversion.  See: 
https://soldersmoke.blogspot.com/2015/05/sideband-inversion.html

Moving the VFO was easy. I am using a variable capacitor with several variable caps on the same rotor.  I just moved from the smallest variable cap to the middle variable cap -- this added capacitance to the system and lowered the frequency.   I also added three additional turns on the coil.  This put me very close to where I needed the frequency to be.  I added one additional 9 pf cap and this put the VFO freq right where I wanted it. 

I was really  glad to include Pete's filter in this receiver.   The mechanical resonator technology fits very well with the very mechanical old-tech theme of this project (it already had a gearbox -- a mechanical filter seemed to fit right in).   It is a fascinating device -- it is almost like having a set of tuning forks all tuned to 455 kc (see above for the RSGB description of how it works).    And having it from from Pete adds a TREMENDOUS amount of mojo, juju, and soul to the new machine. 

Icing on the cake: As I type this, I am listening to Fred K3ZO converse in Spanish with hams all through South America.  Fred preceded me by three decades at the U.S. Embassy in Santo Domingo, but when I got there the local hams were still talking about him  -- he was much loved and admired by the Dominican hams.  TRGHS. See Fred's story here (scroll down a bit): http://www.gadgeteer.us/DRDISP.HTM 

W7RLF Homebrews a Receiver -- FB!

Ryan W7RLF has joined the small and elite group of radio amateurs who have homebrewed a receiver.  And it is a receiver filled with soul, juju and mojo; the project was inspired by Wes Hayward and Farhan, and used components from Hans Summers.   Congratulations Ryan and thanks for all the work you did in documenting your experience. 

Who will be the next intrepid ham to join the homebrew receiver club? 

Hello Sirs!

This month I read Wes Hayward's post on the history and heritage of DC receivers in ham radio and it brought a lingering interest to a head. I had to build one. I run the BITX40 and uBITX group on Facebook, and I posted to the other hams there: Which DC receiver should I build? Farhan recommended his DC40. Mind you, I've never homebrewed a radio before, so this is all new territory for me. 

I did build it, and it does work. It also uses QRP Labs stuff from our friend Hans Summers. This thing has a lot of QRP heritage :) I documented it every step of the way including all of my dumb moves and things I got wrong, and my desire is to inspire others to try homebrewing the way Wes, Farhan, Hans, and you YOU GUYS have inspired me to try it. I am hooked, of course! Here's a link to my blog to Part 1:

https://miscdotgeek.com/building-direct-conversion-receiver-part-1/

It's a four part series (unofficially 5 really) with 8000 words to it, and I hope you guys enjoy it and I'd be ticked pink if was worthy of mention on your show. Here's a video of it too:

https://www.youtube.com/watch?v=ju3kOEyCMYM

73 to you both and I wish you the best!

Ryan Flowers W7RLF

https://miscdotgeek.com

KE5HPY's 12AU7 Quarantine Regen -- FB!

Bill and Pete:

Thanks for upping the frequency of your podcasts.  Each one is a welcome note to break-up the COVID monotony.

Following on to Bill’s 31m rx, I am pleased to have a new regen on the air and performing well.  This started as the 12AU7 Hartley circuit found on the web; however, the original circuit needed some further work IMO.  I made a number of modifications – outboard 30 MHz LPF (to remove our local Spanish FM station), inductive antenna link, variable cap for antenna coupling adjustment, up to 24V on the plate, extra by-passing, NE5532 audio section vs LM386 and a switched cap for a lower “band”.  It’s still a starved triode oscillator/audio amp and it has that regen presence.  Best DX is Singapore (BBC) and Madagascar although it’s ideal for easy listening on 19-60m to Romania, Greece, Cuban music, Spain, etc.  As Bill said, there is still plenty worth listening to on a homebrew AM rx.  40, 30 and 20m copy OK, but bandspread is tricky! Adjusting regen is good for +/- 1 kHz, kind of a poor man’s BFO adjustment.   I heard a TI station calling CQ on 20m and called him back on my Icom for a QSO. 

By the way, this rx has some serious vintage mojo – Hammarlund varicap, National coil form, Millen dial and an RCA tube.  The all-star team plays great together! It’s a kick seeing the filament glow while putting RF through recycled parts made decades ago.

73,

Chuck

KE5HPY