TV Homebrew 84 years ago -- Tracking Down W9YEI's 1939 Television Receiver -- The CRT He Probably Used -- Please Help Find More Info

From October 1938 QST "Building Television Receivers with Standard Cathode Ray Tubes" 

by J.B. Sherman 

A recent Hack-A-Day article about early television receivers got me thinking about the receiver built by young Johnny Anderson in 1939 and described by Jean Shepherd on WOR in 1973.  In the 1973 program (skip to the 18 minute mark),  Shep gives a good description of the device.  It sounded a lot like the receiver from Peter Scozzari's October 1939 "Radio and Television" article:  Shep described a big chassis with angled pieces of aluminum one of which had a tube socket brazed onto it.  Anderson may have bult the power supply on the same chassis as the receiver.  Shep said that a 1 inch CRT was in this socket.  Tellingly, he described the picture as being green in color.  

Peter Scozzari wrote that oscilloscope tubes produced a "greenish hue."  One month after his first article, in November 1939 Peter Scozzari published another article in which he changed the CRT to to a tube that would produce a black and white (not green) pictures.  See below for the part of the article that describes the shift to the larger black and white tube.  This supports the idea that Anderson was using a tube built for oscilloscopes.  The picture above shows what images from the three sizes of RCA oscilloscope tubes would have looked like (absent the green hue -- this was a black and white magazine).  I find them kind of eerie, considering that the person in the picture was probably born more than 100 years ago.  And in that bottom picture we see an image (absent the green hue) very similar to what Shep saw in 1939, and described so vividly in 1973. 

Scozzari's receiver started out with a 2 inch tube, then a month later, he went with a 3 inch tube.  But Johnny Anderson may have only had the 1 inch tube described by Shep.  The Sherman QST article provided circuit details for all three sizes of RCA tubes. This information would have been very useful to Johnny Anderson. So my guess is that when Shep saw TV for the first time in 1939 in Johnny Anderson's basement workshop, he was looking into an RCA 1 inch 913 CRT. 

Here's a great EDN article on the 1 inch CRTs available in the 1930s: 

https://www.edn.com/one-inch-wonders/

Here's a fellow who recently built a TV receiver using an RCA 902: 

https://www.cool386.com/902tv/902tv.html

Here's the YouTube video of his 902-based receiver in action: 

https://www.youtube.com/watch?v=XI8pYs-MBI0

Previous SolderSmoke blog posts on this topic: 

http://soldersmoke.blogspot.com/2022/04/john-stanley-anderson-w9yei-sheps.html

http://soldersmoke.blogspot.com/2022/04/early-television-jean-shepherd.html

http://soldersmoke.blogspot.com/2022/04/w9yeis-homebrew-1939-tv.html

This is all pretty amazing:  We are gathering details on a television receiver built some 84 years ago by a teenager in a basement in Hammond, Indiana.  

Does anyone out there have more information on what Anderson built?  Can anyone dig up more information on this? Any more info on Peter Scozzari?  Anyone have info on Jack Neitz of California (he recently built the Scozzari TV receiver)? 

W9YEI's Homebrew 1939 TV?

 

I've been thinking about Jean Shepherd's 1973 description of the homebrew TV receiver built by his friend Johnny Anderson W9YEI in (probably) 1939.   Shep said Johnny got the info on this receiver from the IRE Journal.  But I was thinking that there had to have been "how to build" articles in circulation around that time, and -- if located -- these articles might provide some insight on what Johnny Anderson built. 

Asked for info on early TV's Google will send you to lots of sites about early commercial sets.  But you have to dig a bit and refine your search to find articles about the kind of receiver that Shep described as having been built by Johnny Anderson.  

The picture above shows one such possibility.  It comes from an article in the October 1939 issue of Radio and Television magazine.  The author was Peter Scozzari.  

http://www.earlytelevision.org/pdf/rtv_10-39-1.pdf

The picture tube seems to be about the size that Shep described;  Shep said it was a 1 inch tube, and this schematic shows a 2 inch tube, but the image must have been smaller, so this seems consistent with Shep's recollection.  The article presents this as a "Low Cost" project -- that would have been what Shep's teenage friends were looking for.  And we KNOW that Anderson was capable of building something like this:  we have a QSL card from him from the same time period in which he notes that he was using a "9 tube superhet."  Someone who could build a 9 tube superhet in 1938 could certainly build this TV receiver.   

Can anyone find more of these kind of articles from the late 1930's? 

Three cheers for Johnny Anderson and for Peter Scozzari. 

More Googling revealed that a Californian named Jack Neitz more recently built the receiver described in Scozzari's 1939 article.  Here is Neitz's build: 

This is really amazing.  We need more info on Jack Neitz!   The only info I have is from: 

https://www.earlytelevision.org/neitz.html

"Patrolling the Ether" WWII Video on Radio Direction Finding Efforts

I heard about this video while trying to track down information on John Stanley Anderson's 1939 television receiver.  "Patrolling the Ether" is kind of hard to find.  It is not really on YouTube.  But there is a good BARC Vimeo video about WWII RDF efforts that includes at the end the full "Patrolling the Ether" video.  

Here it is:  

https://vimeo.com/415926991

Thanks to BARC and to Brian Harrison for putting this together. 

In the video, they discuss the invention of the Panadaptor by Dr. Marcel Wallace F3HM  during World War II.   I set up a very crude Panadaptor using Wallace's principals:

https://soldersmoke.blogspot.com/2019/05/diy-waterfall-quick-and-easy-panadaptor.html

The 17 & 12 SSB Transceiver -- Circuit and Build Info -- Video #4

I REALLY LIKE THIS RIG. IT IS LIKE A MAGIC CARPET THAT CARRIES MY VOICE ACROSS THE SEAS.

Cutting Display Hole sets off smoke alarm. Reverse Polarity Protection. IF and Crystal Filter at 21.470 MHz 50 ohms! TRGHS! Amp for VXO Carrier Oscillator/BFO. Mic Amp from uBITX. Transmit/Receive switching from mic connector. VFO: NO DIE CAST BOXES! HT-37 Variable Cap, Frequency Shift. BP filters from QRP LABS designs (G0UPL). TIA amp boards from K7TFC. Needed RF amp to hear band noise. BITX40 PA design, but RD006HHF1 instead of IRF510. Should I run receiver input through LP filter? Frequency Readout Story: How to use one San Jian counter on two bands.

John Stanley Anderson W9YEI -- Shep's Friend Who Homebrewed a TV Receiver in 1938

 

John Stanley "Johnny" Anderson -- son of John E. and Beda Klarin Anderson, natives of Sweden -- was born on July 19, 1918, in East Chicago, Indiana. He grew up at 6813 (formerly 1439) Arizona Avenue in Hammond, and graduated from Hammond High School a couple of years ahead of American humorist and writer Jean Shepherd. In his WOR radio broadcast of January 24, 1973, Shepherd told of how Johnny was an expert ham who was way ahead of the other kids in town, and how he first saw television demonstrated by Johnny in his basement. Johnny in fact held amateur radio license W9YEI at the time.

After graduation from Hammond High, Johnny went to work as a chemist at the local steel mill. On April 11, 1941, Johnny enlisted at Fort Benjamin Harrison in the U.S. Army, serving through WWII until November 27, 1945. On June 4, 1955, he married Jane H. Vanstone.

Johnny later moved to Munster, Indiana, and continued working at Inland Steel, where he held a variety of technical positions. He passed away on January 29, 1984, at the emergency room of Hammond's St. Margaret Hospital after suffering from neurogenic shock. At the time of his death, Johnny was an electrical technician at Inland Steel's quality control center. He was buried at Elmwood Cemetery in Hammond.  From: https://www.findagrave.com/memorial/173124396/john-stanley-anderson

The Flick Lives web site has an interesting letter that Johnny wrote to his friend Paul Schwartz (W9KPY) in mid 1941.  Schwartz is frequently referred to by Jean Shepherd.  Schwartz was killed in World War II.  

In the letter, Johnny also references another mutual friend who Shep often mentions:  Boles (W9QWK). 

http://www.flicklives.com/files/1941-05-02_093_Johnny_Anderson_to_Paul_Schwartz.pdf

Dorothy Anderson was Johnny's sister and was for a time Shep's girlfriend. 

Rcvr: "9 tube Superhet"  FB OM

Early Television, Jean Shepherd, Homebrewing, and Hack-A-Day

It may have been something like this 1947 receiver.  But with a smaller CRT.

Hack-A-Day has an article about early (1930s) television.  I was immediately reminded of a January 1973 Jean Shepherd show on WOR New York in which Shep talks about a kid in his neighborhood who built a very early television receiver.  You can skip to about the 18 minute mark for the homebrew radio and television stuff. 

In the 1973 show, Shep identifies the builder as John Anderson.   The Flicklives web site lists the hams who lived around Shep in Hammond Indiana.   Among them is John Stanley Anderson W9YEI.  That's him. 

Shep was born in 1921 and in the show he says this all took place when he was 16 or 17.  So that would place these events around 1938.  We see that on February 2, 1939  W9XZV -- the experimental station of Zenith Chicago -- went on the air with television.  In August 1940 W9XBK, the experimental TV station of WBKB Chicago went on the air.  That station was the one Johnny Anderson used to demonstrate TV to Shep and other friends.   

Once again, Shep really captures the spirit of homebrew radio and the way it really captivates teenagers. He also explains -- very well I think -- the difference between true homebrew radio and kit building.  

I really wish we had more details or pictures of W9YEI's TV receiver.  I tried looking in the IRE Journal, but I couldn't find anything.  Anyone have more info on this receiver or ham homebrew TV projects from the late 1930s?

EXCELSIOR!   73   Bill  

https://hackaday.com/2022/04/10/retrotechtacular-a-diy-television-for-very-early-adopters/

https://soldersmoke.blogspot.com/2008/07/best-jean-shepherd-ham-radio-episode.html

http://www.flicklives.com/index.php?pg=318

https://www.earlytelevision.org/w9xbk.html

WD-40: Not Quite the Pope's Pee

This is the second time that Todd K7TFC has sent in a comment that is so good that it gets elevated to the main blog page.  When I was typing yesterday's post about how WD-40 had restored life to the hard drive in my old Tandy 1000 computer, I knew that this would stir up anti-WD-40 sentiments.  I'm grateful that Todd weighed in with such a thoughtful response.  

What can I say?  I was young and foolish.  I thought WD-40 was the answer.  Now I know better.  I have can of DeOxit D5 on my shelf.  I only use the WD-40 on my bicycle.

Todd K7TFCApril 9, 2022 at 7:49 PM wrote: 

I think even the Pope would argue his pee has already served its only real purpose: to remove unwanted substances from the body. WD-40 is useful for that purpose as well--it's pretty good at dissolving and blasting away dirt and grease from tools, hardware, or small mechanisms. That's no doubt why it worked to get your hard-drive spinning again. As a lubricant, though, it is deeply flawed.

If you have nothing else at hand, it can also substitute as an penetrating rust buster. The purpose its developers intended is coded in the name itself: "WD" stands for water displacement, and its very good at doing that. It's not so good at many of the other uses to which it's commonly put.

A very-long time ago, I worked at a company that made its own PCBs, and they had some very-precise NC machinery (programmed with punched tape in those days) for drilling and routing the boards. After a series of baffling and costly shutdowns, the culprit was discovered and WD-40 was banned entirely from the plant. The plant-maintenance guy and janitors couldn't even have any.

It was found that once completely dry, the oils and waxes in it would slowly polymerize (as they were intended), leaving behind a sticky film that protected from moisture and rust just fine, but it gummed up precision machinery. The Chief Production engineer (my father) got the company brass to ban WD-40 entirely.

Why ban it from even plant-maintenance and janitorial work? Because you couldn't keep the PCB-production crew from resorting to it in a "crisis" if they could find any at all in the building. It meant they weren't careful enough to keep the proper lubricants in stock. You could either fire them for their shade-tree-mechanic mentality, or you could ban WD-40.

Needless to say, I've kept my congenital anti-WD-40 animus alive all these years, but I do have a can I use for cleaning and water-displacement purposes. When tempted to use it otherwise, though, the memory of my father sniffing the air suspiciously for its distinctive odor flashes in my head, and I reach for something else. --73, K7TFC  

WD-40, a Hard Drive, a Coat-Hanger Antenna, Dumpster Diving, and Amateur Radio Satellites from the Azores

 

Last month I was talking to Ira VP2EIH on my new 1712 SSB rig.  Ira is interested in satellites.  Talking to him caused me to dig up some old material about satellite operations.   Here is a 2003 QST article about working the satellites from the Azores: 

http://www.gadgeteer.us/AZORESSP.HTM

Regarding the usefulness of WD-40, during my time in the Azores John EI7BA once told me that WD-40 is, "the Pope's pee!"  Apparently that is high praise in Ireland.  It is indeed good stuff. 

Messias CU2BJ is a Silent Key.  I hope Ray CU3GC, WL7CDK is doing well.  

The Vacuum Tube's Forgotten Rival: The Magnetic Amplifier

The video above shows one application of the principal, but be sure to check out the IEEE article:  

https://spectrum.ieee.org/the-vacuum-tubes-forgotten-rival

The First Commercial SSB Trans-Atlantic Radiotelephone System

These guys didn't just complain about QSB -- they DID SOMETHING about it!  

Thanks to AWA and Hack-A-Day for disseminating this great video.  

Tim Hunkin's (The Secret Life of ...) New Series , and First Show (on Sensors) (Video)

Lots of Tribal Knowledge from Tim, the guy who brought us "The Secret Life of Radio" and other wonderful "Secret Life" shows. 

Tim's YouTube channel:  https://www.youtube.com/c/timhunkin1/featured

The Next Time You Hear Someone Complaining About Winding Toroids....

... send them this video. 

Lin is in Hong Kong. What a great job she does with very simple tools.  Notice how she casually mentions that for those parts that have been lost, she will make them herself.  Three cheers for Lin! 

This video reminded me of the people in Santo Domingo 25 years ago who rewound the transformers and RF chokes from my HT-37.  These parts still work.  

Chuck KF8TI recently told me that when he was a Peace Corps Volunteer in the Philippines (1965-1967) he visited a transformer re-winding shop there, seeing piles of insulation and wire on the floor.  Apparently business was good!  

Lin's YouTube channel: https://www.youtube.com/channel/UCpPt42tLH5FRk__ytvMsejw

Video of SolderSmoke Podcast #236

SolderSmoke Podcast #236 is available!

Podcast Posted on 1 April 2022:

http://soldersmoke.com/soldersmoke236.mp3

Winterfest!  Many Boatanchors.  Lots of old good analog test gear.  Talk with Dean KK4DAS.  Met up with Armand WA1UQO and Charles AI4OT. 

Pete's Bench: 

-- Looking for help in software development for MAX2870 board.  

-- Tapped Capacitance Impedance Matching

-- The Pea Shooter (See N2USD's version in videos

 below).

-- Tribal Knowledge on Making Enclosures

Bill's Bench: 

-- 17-12 Band Imaging SSB Transceiver.  It works on both bands. 

-- Plan for Glowing Numerals (N6QW has been there and done that!)

-- WU2D's videos on VFOs.  

-- Temperature Compensation:  HT-37 capacitor.  FT-101 VFO,  even in the ARC-5 receiver! 

-- Trying to get more rigorous about receiver design.  Gain distribution, IMD, Dynamic Range, etc. 

-- Do I need a true RMS audio voltmeter?  Or can I get the same info from freeware audio spectrum analyzer and soundcard?

-- 6EA8s replace 6U8s in MMRX 

SHAMELESS COMMERCE DIVISION:   We have a sponsor!  

PARTS CANDY out of Chicago produces quality test leads for your bench.  The guy who runs the company is Carlos, and he is one of us.  He is an electronic tinkerer. See the ad on the left hand column of the SolderSmoke blog.  Just click on the picture of the test leads and you will be taken to Carlos's ebay store.  Go for it. 

Mailbag

Walter KA4KXX in Orlando -- Diodes in BITX Bilats -- Why?  Farhan says To prevent reverse junction of off transistor from conducting and clipping waveform. 

Tony G4WIF -- Audio test gear and G3ROO paraset

Todd K7TFC Pine boards, TIAs and 12 meters

Dean KK4DAS  Ceramic Variable Oscillators on 40.   Juliano Criteria? 

Mike WU2D   VFOs and Temp compensation. ARC-5s

Chris KD4PBJ   A really nice parts care package -- Thanks Chris! 

Steve M0ECS.  Inspired by SS, moved something off the Shelf or Box of Shame. 

Jason KD2RKN Building a DC receiver.  It is all our fault. 

Chris Mannon in Indiana joining the CBLA

KC4GMH is listening! 

Ed N2XDD has been armed with a 3.579 MHz crystal.  

Harvey Wa3EIB working on his museum 

Tim AG4RZ is BACK IN THE SOLDERSMOKE! 

Fred KC5RT -- an old friend -- recommends Bangood RF sig gen for 88 bucks. 

Shlomo 4X4LF listening and homebrewing from a Kibbutz in Israel. 

Chuck KF8TI was a Peace Corps Volunteer in the Philippines. 

SolderSmoke Podcast #236 -- Bill's 17-12 Rig, Pea Shooter, VFO Wisdom, Temp Compensation, Need Code for Max2870, Making Enclosures, MAILBAG

ARC-5 R-23 Nav Receiver Parts

SolderSmoke Podcast #236 is available!

http://soldersmoke.com/soldersmoke236.mp3

Winterfest!  Many Boatanchors.  Lots of old good analog test gear.  Talk with Dean KK4DAS.  Met up with Armand WA1UQO and Charles AI4OT. 

Pete's Bench: 

-- Looking for help in software development for MAX2870 board.  

-- Tapped Capacitance Impedance Matching

-- The Pea Shooter (See N2USD's version in videos

 below).

-- Tribal Knowledge on Making Enclosures

Bill's Bench: 

-- 17-12 Band Imaging SSB Transceiver.  It works on both bands. 

-- Plan for Glowing Numerals (N6QW has been there and done that!)

-- WU2D's videos on VFOs.  

-- Temperature Compensation:  HT-37 capacitor.  FT-101 VFO,  even in the ARC-5 receiver! 

-- Trying to get more rigorous about receiver design.  Gain distribution, IMD, Dynamic Range, etc. 

-- Do I need a true RMS audio voltmeter?  Or can I get the same info from freeware audio spectrum analyzer and soundcard?

-- 6EA8s replace 6U8s in MMRX 

SHAMELESS COMMERCE DIVISION:   We have a sponsor!  

PARTS CANDY out of Chicago produces quality test leads for your bench.  The guy who runs the company is Carlos, and he is one of us.  He is an electronic tinkerer. See the ad on the left hand column of the SolderSmoke blog.  Just click on the picture of the test leads and you will be taken to Carlos's ebay store.  Go for it. 

Mailbag

Walter KA4KXX in Orlando -- Diodes in BITX Bilats -- Why?  Farhan says To prevent reverse junction of off transistor from conducting and clipping waveform. 

Tony G4WIF -- Audio test gear and G3ROO paraset

Todd K7TFC Pine boards, TIAs and 12 meters

Dean KK4DAS  Ceramic Variable Oscillators on 40.   Juliano Criteria? 

Mike WU2D   VFOs and Temp compensation. ARC-5s

Chris KD4PBJ   A really nice parts care package -- Thanks Chris! 

Steve M0ECS.  Inspired by SS, moved something off the Shelf or Box of Shame. 

Jason KD2RKN Building a DC receiver.  It is all our fault. 

Chris Mannon in Indiana joining the CBLA

KC4GMH is listening! 

Ed N2XDD has been armed with a 3.579 MHz crystal.  

Harvey Wa3EIB working on his museum 

Tim AG4RZ is BACK IN THE SOLDERSMOKE! 

Fred KC5RT -- an old friend -- recommends Bangood RF sig gen for 88 bucks. 

Shlomo 4X4LF listening and homebrewing from a Kibbutz in Israel. 

Chuck KF8TI was a Peace Corps Volunteer in the Philippines. 

Mike WU2D Looks at the "Dream" SW Receivers of the 1960s and 70s (Video)

Wow, I really liked Mike's walk down memory lane. I saw several of my own dream receivers: 

S-38E.  Indeed, this little monster did add some danger to your life.  AKA "The Widow Maker," I gave one to my cousin's husband so he could listen to what the commies on Radio Moscow were saying.  He later told me that the receiver had given him a shock.  I now have TWO S-38Es in my shack (two more than I really need).  I have installed isolation transformers in both of them, so they have lost the one element (danger!) that made them attractive.  

HA-600A. I got this one for Christmas in 1972.  The A model is MUCH better than the plain vanilla HA-600.  I recently got another HA-600A and found serious deficiencies in the Product Detector.  Has anyone else noticed these problems?  BACKGROUND INFO AND A PLEA FOR MORE INFO HERE: https://soldersmoke.blogspot.com/search?q=HA-600A+Product+Detector

HQ-100.  Got one in the Dominican Republic.  Fixed it up, repairing damages caused by radio life in the tropics.  Disabled the goofy audio amplifier circuitry.  I now wonder if this receiver might benefit from the insertion of a 455 kc ceramic filter. 

NC190.  Wow "Cosmic Blue"  Perhaps this was an early influence that led to "Juliano Blue?" 

HQ-180.  "18 tubes and almost as many knobs!"  FB!  

HRO-500.  Love the dial. 

Transoceanic.  Never had one, but built a BFO for the Transoceanic that W8NSA took with him to SE Asia during the war. 

R-390A.  I don't have a crane for the workbench.  

Thanks Mike -- that was a lot of fun.  

Vienna Wireless Winterfest Hamfest 2022

After a two-year pandemic hiatus, yesterday the Vienna (Virginia) Wireless Society's annual "Winterfest" hamfest was back.  And the weather was in fact COLD -- it definitely felt like Winterfests of years-gone-by. 

Club President Dean KK4DAS kindly invited me to participate in a forum on homebrewing.  You can watch the presentation STARTING AT 2:04:06 (hours:minute:seconds) here: 

https://www.youtube.com/watch?v=s48of3uS9tM

It was especially cool to be able to tell the audience about Pete N6QW and Farhan VU2ESE. We talked about Pete's Simple SSB transceiver, the Michigan Mighty Mite and the BITX rigs. 

Some observations on the hamfest scene: 

-- There are lots of boatanchor radios out there, and it seems like a buyer's market.  These old rigs do not seem to be selling nearly as fast as they did a few years ago. 

-- There is a lot of older analog test gear on sale too, and it too seems to no longer be as in demand as it was a few years ago.  Perhaps the availability of cheap, small, and very effective digital oscilloscopes is affecting the sale of these once sought-after items. 

My purchases: 

-- A really old beat-up (crashed?) ARC-5 R-23 receiver.  I have already extracted the variable capacitor. 

-- A nice box of smaller variable caps. 

-- 100 feet of 550 parachute cord. 

-- Two nice metal chassis/boxes 

-- A bag of shaft adapters/connectors

With Armand WA1UQO (left) and Steve Boles W4SB (center)

With Charles AI4OT 

Thanks to Dean KK4DAS and the entire VWS team for a great event. 

Getting More Rigorous About Receiver Design (Video)

As I finished up the receiver on my 17-12 SSB transceiver, I started to wonder -- how good is it?  

Sure, I could hear stations on both bands, and when I got started as a homebrewer that was enough for me. But now, I find myself wondering about receiver performance.  Did I get the gain distribution right?  Do I have too much gain ahead of the mixer?  Ahead of the crystal filter?  Is the receiver generating too much noise?  Can I hear the band noise?  If not, why not?  Do my circuits lose linearity in the presence of strong signals?  What is my dynamic range?

This is a big complicated subject that takes time to master.  

I am just beginning.  I found the video above to be very helpful. 

I was jealous of this fellow's audio spectrum analyzer, but then Tony G4WIF told me that the the analyzer that this fellow was using was really just a sound card and some software.  I quickly found a similar piece of free software that lets me do the same thing he did:  Look at the audio output of my receiver and watch what happens as I put an RF signal of varying levels into the antenna port.  

I am using Visual Analyzer, a free program out of Italy: 

https://www.sillanumsoft.org/   

 The author of the software seems very cool" 

My name is Alfredo Accattatis; I love electronics and software, and I have been working for years in commercial companies as software/firmware engineer and software designer. I've been writing programs for embedded systems (with DSP and MICROCONTROLLERS), for PC, for Avionic Computers and even for Mainframes, using C, C++, Pascal, Ada, REXX and assembly. I starting write VA during my free time just for fun and using (also) my DSP experience. The program was and is completely FREE.

More info about Alfredo here: 

https://www.sillanumsoft.org/about_the_author.htm

Do you folks think I need to buy the kind of True RMS Audio Voltmeter that is being used at the end of the above video? 

First Ever Contact on 12 Meters: Homebrew, QRP, SSB, DX (Video)

I've recently finished most of the circuitry on the 17-12 meter dual band SSB transceiver. I have had contacts with it on 17 meters, but until yesterday morning (March 22, 2022) I had not had any contacts on 12 meters. This morning I talked to Paul EA5JZ in Valencia, Spain. I was running the 17-12 rig barefoot at about 5 watts with the final being one RD06HHT FET. The antenna was my 75 meter doublet fed with window line -- I had to modify the tuner to get it to work on 24.9 MHz. It was very cool to have my first 12 meter contact be QRP, HB and with Spain.

There is a LOT of soul in this new rig.  Here is a partial list of contributors: 

-- Overall BITX design:   Farhan VU2ESE

-- Termination Insensitive Amplifiers (TIA):  Wes Hayward W7ZOI and Bob Kopski K3NHI.  

-- TIA boards from Todd K7TFC

-- ASK-1 Mixer from Armand WA1UQO

-- VFO design parameters from Joe Carr K4IPV (SK) 

-- VFO stability ideas from Frank Harris K0IYE and Mike Murphy WU2D. 

-- HT-37 Tuning Capacitor bought from e-bay at suggestion of Pete Juliano N6QW. 

-- Pine board base of the rig:  Frank Jones (SK) W6AJF's preferred building technique. 

-- DTC Band-Pass filter circuits from Han Summers G0UPL. 

-- Low pass filter values from G-QRP web site. 

-- Idea of using RD06HHT instead of IRF-510 in the final:  Pete Juliano

-- Heat sink from Chris KD4PBJ

-- Trifilar Toroids used in many places from Farhan VU2ESE.

Thanks to all.  73  Bill  

Receiver Dynamics -- How Good is my Receiver?

OK , so I've finished building my new 17-12 Dual Band SSB Transceiver.  I am now testing it out on both bands.   A big question I have is this: how good is my receiver?   Did I get the gain distribution right?   Is it generating too much noise?   Are any of the stages too vulnerable to distortion in the presence of large signals?  

These kinds of questions are at the heart of receiver design.  Many of us have for years just thrown together amplifiers oscillators and mixers, and have been pleased if we could copy signals on the ham bands.  But could we have been doing it better?   

This is a very complicated issue, and unfortunately much of the literature is plagued by jargon and unnecessary complexity.  Rarely do we find something that goes from the general to the specific and explains what it is we are trying to achieve:   We want the receiver to be sensitive, but we don't want it to be so sensitive that it distorts with strong signals.  It will make some noise, but we don't want the receiver's internal noise to be stronger than the noise coming in from the antenna.  The "front end" stages are very important because any flaws there will be amplified by the follow-on stages and will "cascade" down through the receiver.  Bandwidth is very important. 

This morning I found (again!) a document that defines terms in a very clear way.  Be sure to check out the footnotes mentioning Dave Newkirk and Wes Hayward!  FB!  Here it is:

https://www.nsa.gov/portals/75/documents/news-features/declassified-documents/cryptologic-quarterly/Receiver_Dynamics.pdf

17 - 12 Dual Band SSB Transceiver On-The-Air

 

It is still completely al-fresco, with all the guts exposed, but I got it on the air this morning.  I was 17, running it through my CCI  .1kW  100 watt amp to a tuned doublet.   Four QSOs so far: HP3SAM, K5BM, N4ZUL, and II3WRTC.   

The structure of the rig is basically BITX. 

The blue boards you see are TIA boards developed by Todd K7TFC. 

No major problems to report.   I will try it out on 12 meters  soon.  The receiver was working well on that band.