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Thursday, April 28, 2022

Wednesday, April 27, 2022

The Story of Television (Sarnoff's Version) -- 1956 Film


Of course, this has to be taken with a huge grain of salt.  "General" Sarnoff sits there and claims that Vladimir Zworkyin "invented" electronic television.  But Philo Farnsworth really did that.  Zworykin's claim to invention has about as much validity as Sarnoff's claim to having been a General!  

But still, there is a lot of interesting info amidst the RCA propaganda.  Again, it is really striking how far they had come before WWII put things on hold for four years.  

Tuesday, April 26, 2022

Level UP EE Lab Builds a Superhet Receiver


I was really glad to have stumbled across Darren's YouTube channel: 

Heck, he has an S-38E on the shelf above his bench.  He is clearly one of us.  What is his callsign?  

This morning I watched the first and last of his 10 videos on his superhet receiver project.  Very cool.  Lots of good info in there.  And there is something for everyone:  Arduinos and Si5351s, along with a lot of standard analog circuitry.  The first episode appears above. 

The variable bandwidth filter looks very interesting. And there was a nice shout-out to Charlie Morris and one to Hans Summers. 

I really like his effort in episode 10 to measure Minimum Discernible Signal using commonly available test gear.  This helped me in my effort to get more rigorous and serious about receiver performance measurement.    

Darren has many other excellent projects on his YouTube channel.  My Hammarlund HQ-100 receiver started giving me trouble this week, and I was debating whether or not to fix the old thing.  Darren's channel provided the inspiration I needed.  It will be fixed!   

Please subscribe to Darren's channel.  And spread the word about his videos.  We definitely want him to make a lot more.  

Thanks Darren! 

Words of Wisdom on Which Tools to Buy


Also interesting are Van Neistat's thoughts on workshop design: 

Monday, April 25, 2022

75/20 - 17/12 Two Homebrew Rigs in Scrap-Wood Boxes

 



I moved the 17/12 Rig off the workbench and placed it (as planned) atop the Mythbuster rig.  Now I have four bands easily accessible.  In these pictures you can see all four bands being displayed on the San Jian Frequency Counters. 

I found a kitchen drain screen that is an ideal cover for the 3 inch speaker in the 17/12 rig. 


I reconfigured the Low Pass filters in the CCI .1 kilowatt amplifier.  I put a 12 meter LP filter in there in place of the 40 meter LP filter (that I haven't been using much). 

I have been working a lot of DX on both 17 and 12.   

Sunday, April 24, 2022

Back to the 1970's! Homebrew Keyboards! Don Lancaster's TV Typewriter


Even though it is outside my normal analog comfort zone, I really liked this video.  Farhan sent it to me, along with this note: 

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

As a kid, do you remember Don Lancaster's books? I learnt most of my digital electronics from him. I still have the 7 dollar video generator book on my shelf. He predates the Homebrew Computer Club. In fact, he is probably the reason for the HCC, because he put in the pieces that were used by others like the two Steves to build their own computers.
His most brilliant hack was to build a "TV typewriter" out of standard TTL parts that were just coming out in the surplus market. For $120, you could, if you build etched your own PCBs and managed to pry parts of fellow builder's dead fingers, build a circuit that, if you typed your name, it showed up on the TV screen! Never mind that dad wanted to get back to watching football or mom wanted the kitchen counter to be cleared out. Those days, parents had no appreciation for their kids being on TV, I guess.
In an earlier hack, he encouraged people through his articles in Radio Electronics to build their own Qwerty keyboard. With this in hand, you could, um .. um... well type something and sit back. There was nothing to connect it to. The fun thing was, there were no key switches available. You had to build those as well. Wind your own springs, make your own keytops, Once it was built, you could use a VOM to check that the ASCII bits corresponding to the key you held down would correctly show up on the 7 data lines. I guess the girls were surely impressed. You just needed to carry the power supply with +5, -5v, +12v, the keyboard itself, an ASCII chart and a VOM to school to show off.
Jokes apart, he kept building things and builds them to this day. His TTL cookbook and CMOS cookbooks were the goto books for almost all digital elecctronics hackers. It is a pity that no one acknowledges his knack. He has scanned in a few of his books on his 1990s www.tinaja.com.  Check  https://www.tinaja.com/ebooks/cmoscb.pdf
Why does it concern us? He is K3BYG, that's why.
- f

-----------

 So many things from the video resonated with me: 

-- The importance of building and testing, stage by stage.  The narrator admits "I might have screwed that up."

-- Homebrew keyboards!  Make your own keyboard springs you pathetic appliance operators! 

-- Wood box. 

-- Origins of ASCI

-- The scary 1970s.  Indeed.   I started High School in 1972. 

-- Schematic errors!   Oh the humanity!  Erratas. 

-- Appeals to the Digital Gods. (Not as powerful as The Radio Gods.)

-- A Gimmick Twin Lead. 

-- "So many different disciplines went into building this thing..." 

-- A taste of the home computing revolution of the 1970s. 

-- Farhan is right -- he was K3BYG.  But that call now seems to belong to someone else. 

Don Lancaster's unofficial autobiography: 

https://www.tinaja.com/glib/waywere.pdf

Clearly, Don Lancaster has The Knack! 

Saturday, April 23, 2022

Looking at the World Through a 1 inch Cathode Ray Tube (the RCA 913) (videos)


Joh DL6ID sent me the above video.  We have been e-mailing each other about the W9YEI Television Receiver built in 1939 or so.  We have kind of concluded that the builder used an RCA 913 tube as the CRT.  This was an oscilloscope tube and was often described as looking like a metal 6L6 with a tiny screen on top.   This is kind of neat -- like using something from the old days to peer into the new world of video.  

We wondered about the image persistence of this tube.  Fortunately for us, we found several YouTube videos showing recent builds or repairs of oscilloscopes with RCA 913 tubes.  

Of course, Mr. Carlson has a video on one of these devices (and -- as expected -- has another in his junk box.  Mr. Carlson has at least two of everything.) 

Here are a few other videos showing RCA 913 tubes in action. 


https://www.youtube.com/watch?v=IfN2mmEIfTE   (with Men at Work audio)

https://www.youtube.com/watch?v=TJF22Ra2kIM    (Summertime.... And the Livin' is Easy)

Here's a nice video from Tektronix on CRTs: 

Friday, April 22, 2022

1942 (?) RCA Film on Tubes, Radio, Research, and Television


Here is a very interesting video from RCA.   It was released in 1942,  but it looks to me as if it was produced BEFORE the Pearl Harbor attack and the U.S. entry into World War II.   There is no mention of the war nor of RCA's support for the war effort.  All films like this that were produced during the war have a lot of material about how the company was contributing to the war effort.  So I think this is really a pre-war film. 

Early in the film they link the origins of RCA Labs to a decrepit "radio shack" at Riverhead, Long Island (NY) in 1919.   Here is some background on this: 
and

In this film we see Vladimir Zworykin (boo, hiss) of TV fame (no mention of poor Philo Farnsworth),  and we also see Harold Beverage, the creator of the antenna that bears his name.   There is what must have been one of the first "electronic clocks."  

At the end, the segment on television is really interesting.   It is amazing how far they had gone with TV before the war.  

Wednesday, April 20, 2022

Conclusions About W9YEI's Early (1940?) Homebrew Television Receiver

It may have looked something like this.  Recent build of the Scozarri receiver by Jack Neitz

Joh DL6ID and I have been exchanging e-mails in which we compare notes on the early homebrew television receiver of Johnny Anderson W9YEI.   In 1973 on WOR New York, Jean Shepherd described a very memorable demonstration of TV  conducted some three decades earlier by Anderson for teenage friends in Hammond, Indiana.  Shep provided a lot of detail, but some of his recollections seemed a bit off;  Shep was known for exaggerating or changing details to make a story better.   

We have arrived at some conclusions about this project (but if anyone has more info, please let us know): 

DID ANDERSON ACTUALLY BUILD A TV RECEIVER?  

Yes, he did.  This was a homebrew project, not a kit build and not the use of a receiver built and loaned for test purposes by the transmitting station.  Anderson was an accomplished homebrewer whose basement, according to Shep, was filled with devices he had built.  A QSL card sent by him in 1938 shows him using a "9 tube superhet" as a receiver.  Shep describes Johnny -- over a period of perhaps six months -- gathering components  in Chicago's electronics parts market, and building something in his basement.  That sure sounds like a real homebrew project.  A TV receiver kit was available, but it was very expensive, and Shep would have immediately denounced it as a non-homebrew project.  Anderson homebrewed the receiver. 

WHY DID HE DO THIS? 

Why would a ham build a TV receiver at a time in which there were only a few experimental transmitters on the air, and no possibility of using the receiver to "work" other amateur stations?  We tend to think of TV as a post-war commercial phenomenon.  But in fact there was a lot of "buzz" about TV in the 1930s.  Magazines were filled with TV articles, and with ads for courses that promised to prepare people for what seemed to many to be "the next big thing."  The World's Fair in Chicago in 1933 and 1934 featured a demonstration of television -- Anderson, who lived in a close-in Chicago suburb,  may have seen this demonstration.  Television must have seemed like a do-able but difficult technical challenge, and would  have attracted the interest of an advanced homebrewer like Anderson.    

WHEN DID ANDERSON BUILD THE RECEIVER? 

Shepherd describes a demonstration of TV in which Anderson tuned into experimental transmissions of WBKB in Chicago.  WBKB's experimental transmitter W9XBK did not go on the air until August 1940.  And Anderson told Shep that he had been calling in reception reports for a month or six weeks.  That would push the date of the demonstration to September 1940 at the earliest.  In September 1940 Anderson was 22 years old, and Shep was 19. (Here is one area in which Shep's recall is questionable -- he claims that the event took place when he -- Shep -- was 16 or 17.  In fact he was older, but having the protagonists a bit younger made the story more intriguing.)   If we assume that it took Anderson six months or so to build the receiver,  that would push the start date of Anderson's build to around March 1940.  

There was another experimental station on the air in Chicago: Zenith Corporation had W9XZV doing experimental transmissions starting on February 2, 1939.  If Anderson had built the receiver a bit earlier, he could have been tuning into W9XVZ before W9XBK went on the air.  But I think it was more likely that he started building in early 1940.  I get the feeling that the Scozzari articles of October/November 1939 influenced his build.  

WHAT PUBLICATIONS GUIDED ANDERSON? 

Shep, in extolling Anderson's advanced, self-taught knowledge of electronics tells us that Anderson was at his young age already reading the IRE Journal, the monthly publication of the Institute of Radio Engineers. Joh DL6ID notes that Shep said that this publication was being sent to Anderson, indicating that he had some form of subscription.  He may have also had access to back-issues in a Chicago library.  Anderson was a serious consumer of technical material. 

The IRE Journal had many articles about television, but they were highly theoretical.  Typical of this was the December 1933 issue.  Anderson probably also benefitted from more practical, build-related articles that appeared in publications like QST, Shortwave and Television,  and Radio and Television. 

In December 1937 QST began a series of articles on television my Marshall Wilder.  

In March 1938 CW Palmer launched a series of build articles on TV receivers in the Gernsback magazine "Shortwave and Television." See photo below. 

In October 1938 QST started a series of practical build articles on TV by J.B. Sherman.  This series provided circuit details on how to use three different sizes of RCA oscilloscope CRTs, including the small 1 inch 913 tube. 

In December 1938 QST continued with the television theme,  presenting the first in a series of build articles by C.C. Schumard. 

In October 1939 Peter Scozzari launched a good series of build articles in Radio and Television magazine.  See photo below. 

WHAT CATHODE RAY TUBE DID HE USE?  

Many of the publications of the era carried projects using 2 or 3 inch CRTs.  But it appears that Anderson had a smaller, 1 inch oscilloscope CRT in his project.  In his 1973 broadcast, Shep repeatedly called the CRT "tiny" and refers to it as a 1 inch tube.  Shep said the image produced was green, indicating a tube built for oscilloscopes.  He may have used a 1 inch RCA 913 CRT Tube. See the Sherman article in the October 1938 QST

THE DEATH OF ROSS HULL

In the middle of all this, on September 13, 1938 radio pioneer Ross Hull was electrocuted while working on his homebrew television receiver. 

The Palmer Receiver

The Scozzari receiver -- Power supply on separate chassis

Previous SolderSmoke Daily News posts about this project: 

Tuesday, April 19, 2022

Young Jean Shepherd Gets Hung-Up On Ham Radio

Oh man, we've all been there:  OBSESSION with ham radio.  Shep went over the top and didn't sleep all weekend when his homebrew transmitter was finally neutralized and started to put out a decent signal on 40 meter CW.  

One of my favorite lines in this episode is about how, before the neutralization, the transmitter had had so many parasitics that it would continue to transmit for two hours AFTER Shep turned it off, "and all on the wrong frequencies."  

I found this while searching for other Shep references to Johnny Anderson, the guy who built the TV receiver.  Please let me know if you know of any other Shep references to Johnny. 

Here is the program.  Skip ahead to 20:50 

https://www.radioechoes.com/?page=play_download&mode=play&dl_mp3folder=T&dl_file=the_jean_shepherd_show_1963-03-07_hung_up-ham_radio.mp3&dl_series=The%20Jean%20Shepherd%20Show&dl_title=Hung%20Up-Ham%20Radio&dl_date=1963.03.07&dl_size=8.87%20MB

EXCELSIOR!  


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