Podcasting since 2005! Listen to Latest SolderSmoke

Showing posts with label UK. Show all posts
Showing posts with label UK. Show all posts

Wednesday, November 1, 2023

Basil Mahon is an Author for Us -- He explains Faraday, Maxwell, and Heaviside

 

Armand WA1UQO has sent me two of Basil Mahon's books.  They are both really great.  He is a wonderful writer who has the rare ability to present not only the people who made the discoveries, but also the technical details of the discoveries themselves.  There is so much to learn from Basil Mahon's books.  I put a link to one of them on the column to the right >>>>>>>>>>>>>>>>>>>>>>
I bought his book on Maxwell so I can read it on a long flight our to California.   

PERSONAL:

Born May 26, 1937, in Malta;  married Ann Hardwick (a teacher of chemistry), April 1, 1961; children: Tim, Sara, Danny. Education: Attended Royal Military Academy, Sandhurst, 1955-57; Royal Military College of Science, B.Sc., 1960; Birkbeck College, London, M.Sc., 1971. 

Check out his career: 

British Army, career officer, serving with Royal Electrical and Mechanical Engineers in Germany, Aden, and United Kingdom, 1955-74, retiring as major; Government Statistical Office, civil servant, 1974-96. Consultant and trainer on censuses and statistics, including work for clients in Russia, Estonia, Croatia, and Republic of Georgia.

And his thoughts on writing: 

Basil Mahon on writing: "To me, the joy of writing is simply the chance to give readers the joy of reading—to share one's thoughts and passions with them, hoping to leave them with a feeling of pleasure and well-being. By the time I came to write The Man Who Changed Everything: The Life of James Clerk Maxwell, careers in the army and the civil service had given me plenty of practice in writing instructions—where crispness and clarity were the cardinal virtues—so the big test was to try to hold fast to these qualities and to entertain the reader at the same time."

From the Netherlands, Manu Joseph explains why he loves Mahon and Forbes' book on Faraday and Maxwell: 


Thank you Armand, and thank you Basil Mahon. 

Sunday, October 15, 2023

Spy Rigs, Para Sets, Bugs, and Enigma Machines -- Dr. Tom Perera W1TP (video)


This is a really amazing presentation by Tom Perera W1TP to the Fairlawn (NJ) Amateur Radio Club. 

There is so much great info in this presentation.  Some of the highlights for me: 

-- The U.S. Civil War telegraphic (wired) spy set was just mind blowing.  I had never heard of this.  

-- The way the Nazis transmitted a signal 1 kc off the BBC frequency, so that Germans who tuned their Nazi-issued receivers to the BBC could be detected by neighbors (from the resulting 1 kc tone!) and turned in to the Gestapo.  

-- "Things don't land gently when dropped by parachute." Indeed.  This was a reminder of the courage of the young women who parachuted into Nazi-held territory during WWII.  Like Paulette.  It was great to see her with her Paratrooper wings on.  AIRBORNE!  And the picture of the operator with the bicycle generator was of Virginia Hall.  See: https://www.npr.org/2019/04/18/711356336/a-woman-of-no-importance-finally-gets-her-due  That portrait hangs in the hallway of the National War College. 

-- How they put the schematic of the PRC-5 right into the box.  Great idea.  But it had a terrible receiver.  One of the schematics showed a 455 kc IF and a BFO.  So they sent in superhets, not just regens. 

N2CQR operating the Para Set of G3ROO around 2009

This video makes me want to build a Para Set. 

Thanks a lot to Tom W1TP and the Fairlawn ARC. 

Saturday, August 19, 2023

Valveman -- The Story of Gerald Wells


Don't be deterred by the annoying test patterns at the start of this video.  Just skip past them.  The rest of the video is quite good.  Or you could just click on this link and avoid the first 83 seconds of test pattern:  https://youtu.be/Y8w6iwaAGJ4?t=83

Gerald Wells has been mentioned on this blog before, but I don't think we've ever presented the full documentary on this fellow.  Here it is.  Gerry is clearly one of us: a radio fiend, obsessed (as he admitted!) with wireless, a victim of THE KNACK.   

George WB5OYP of the Vienna Wireless Society got to meet Gerald Wells and visit his museum. George alerted me to this video.  Tony G4WIF also was able to visit Gerry and his museum. 

The documentary is full of interesting stuff, and is, in itself, a Knack Story.  Wells mentions the Crippens murder so well described by Eric Larson in "Thunderstruck."  It was this crime that brought radio to the center of public attention.  

Tuesday, June 13, 2023

How they Make Raspberry Pi 4 Single Board Computers


So, if the Raspberry Pi is a key part of your new "homebrew" rig, how much of the rig did YOU actually build? 

Friday, April 28, 2023

Who is the Man in the Portrait in Artie Moore's Shack?

 


Who is this person?   He is in a prominent position in Artie Moore's very early radio shack.  Artie was obviously big on labeling things, and there is a label under the picture but I can't make it out.  What do you folks think?  Who is this?  

Monday, April 24, 2023

Tim Hunkin on Drilling Holes (Secret Life of Components Video)

 I guess that aside from being a great video, this is something of a test of technical nerdy-ism.  If you find this hour long video really interesting, well, you know... 

Really cool stuff from Tim Hunkin: 

-- I liked the angle driller.  Need one. 

-- The placement of the magnets near the hole to catch the shavings was really cool. 

-- Tim's reluctant admission that it is just better to buy new drill bits (as opposed to sharpening old ones) is good advice. 

-- WD-40!  Yea! 

-- Note:  No white "Boffin" coat for Tim.  Just "overalls."  But as I watched I found myself thinking that he could probably have used an armor plate or at least a Kevlar vest amidst all that flying metal. Perhaps a bit more eye protection too...  

-- Fiddley.  A useful tech term.  

--Swarf:  Another useful tech term:  the metallic remnants (shavings) of drilling. 

-- The digi readout on the milling machine looked really useful. 

Finally, I loved the sign that Tim has posted in his workshop:  

SMALL HADRON COLLIDER

Four Old BBC Shows on Radio: Hams, Physics, and Antique Wireless


The first one, about ham operators in general, is pretty depressing. Then it goes downhill as they shift to those who are listening to baby monitors and cell phones.  Yuck. 

The second one seems to show some physicist having understandable difficulty explaining particle-wave duality in a short TV segment.  

There is a short bit (that I didn't quite get) about the BBC's "Teddy Bear's Picnic."  

The final one is about Gerald Wells and his Antique Wireless Museum in South London.  Note the white coat -- clearly a boffin.  For a while I confused him with Rupert Goodwins G6HVY (similar white coat, but a different bloke).  

Thursday, April 20, 2023

Artie Moore and the Titanic


I had never heard of Artie Moore, but his is a very interesting story from the earliest days of radio. 

 https://en.wikipedia.org/wiki/Artie_Moore

https://www.facebook.com/groups/118053768802799



Friday, April 7, 2023

More Info on the Cuban Jaguey Solid State DSB Transceiver

ZL2BMI Transceiver Layout (not full size here!) 

Continuing our search for information the Cuban "Jaguey" DSB rig, Trevor Woods pointed me to Dick Pascoe's QRP column in the (below) July 1998 issue of Ham Radio Today.  I think the first SPRAT article about Eric Sears' ZL2BMI DSB rig was in SPRAT 83 in the summer of 1995.  This fits well with the sequence described below by Arnie Coro CO2KK. 

I am still looking for a schematic and pictures of the Jaguey rig: If you can help in this, please let me know.  


Speaker Made from Potato Chip Bag: Tim Hunkin's Solenoid and Electromagnet Video


The potato chip ("crisp") speaker is very cool (I have it cued up here), but the rest of Tim Hunkin's video is also wonderful and worth watching.  (Note:  Posh bags work better as speakers.) 

Thinking of our use of signal relays, I kept wanting Tim to tell viewers to put a diode and a capacitor across the relay terminals to prevent back EMF from frying circuits.  But I guess this is not much of a problem with the arcade games that Tim builds.  

As always, Tim's scrounging and use of discarded parts is really admirable.   

I noticed in the credits that he is dedicating these videos to the memory of his colleague Rex. 

Thanks to Chuck WB9KZY for bringing this video to our attention.  And thanks Tim. 

Tuesday, November 15, 2022

Amazingly Cool MONTV Video on Direct Conversion Receivers with Glue Stick PTOs


I think this is one of Nick's best videos. And he has made a lot of good ones. 


This is a really excellent description of how a Direct Conversion receiver works. But more importantly Nick really captures the joy of building one of these receivers using discrete, analog components, including a Permeability Tuned Oscillator made from our beloved Glue Sticks.  

Extra mojo comes in the form of a mixer designed by Pete Juliano using J310s to simulate a 40673 dual gate MOSFET.  Fantastic.  Icing on the cake comes from a W8DIZ AF amp out of SPRAT magazine. 

There is a grand finale.  I won't spoil it.  Watch the video. Suffice it to say that Farhan would be pleased with this.  

Great stuff.  Thanks Nick!  

Friday, October 7, 2022

How the Diode Ring Multiplies by 1 and -1 -- "The Secrets of the Diode Ring" -- Plus another Bandsweep with the DC RX


A deeper look into how the Diode Ring detector works: "the particular go of it." Here I rely on a wonderful diagram from the RSGB. This diagram clearly shows how in this circuit, the switching action of the diodes -- controlled by the VFO -- results in sum and difference frequencies at the output. This is amazingly illuminating. I then tried to build this actual circuit. It works, but I am also getting a lot of AM breakthrough from a local AM station (WFAX) and Radio Marti at 7335 kHz. I will try again. In any case, the diagram shows how the diode ring does its thing! I need to beef up the Band Pass Filter. I tuned around a bit on 40 meters -- you can listen. Students at a local high school have been trying to get the DC receiver I loaned to them going -- they may be confused by the intricacies of SSB tuning. I will see them next week.

Here is the RSGB diagram that reveals the secrets of the Diode Ring.  (Now that could be the title of a book or movie.  I claim the rights to that!)  Click on the image for a better view. 

Tuesday, October 4, 2022

Tim Hunkin's "The Radio Set" Drawing, and The Secret Life of the Radio (Remastered)

 

Click on the image for a better view. Click here for the whole drawing: 

I really liked this, and there is a lot more like it on the site of Tim Hunkin, the fellow who made all the great Secret Life of Machines shows.  His site: https://www.secretlifeofmachines.com/index.shtml

They remastered the show about radios.  It is worth watching: 

Thanks Tim! 

Wednesday, September 21, 2022

Nick's "Shelf-17" Al Fresco Homebrew Transceiver -- Frank Jones Would Approve!


This is a really wonderful video from Nick M0NTV.  

Some reactions:
 
-- Wow, a real celebration of Al Fresco!  And of the wooden chassis -- Frank Jones would be so pleased. 

-- Nick's description of the tales of woe caused by metal boxes is right on the mark, as is his description of the benefits of leaving the circuitry visible.  He's right -- this is an art and science kind of thing. 

-- That's a shelf, but it is FAR from being a shelf of shame! 

-- I am jealous of the S-meter.  I may need to include one of those in future rigs. 

-- Great to hear the shout outs to VK3HN, ZL2CTM, and N6QW -- we are are indeed the IBEW! 

-- I think we can see the N6QW influence in Nick's decision to use a steerable filter/IF amp board.  FB. 

-- I liked hearing Helio PV8AL in Boa Vista.   When I was building simple Direct Conversion receivers for 40 meters, I knew that I had it right when I could hear Helio's roosters in the morning! 

Be sure to watch this video, and to subscribe to Nicks Channel: https://www.youtube.com/c/M0NTVHomebrewing
He has done many other videos providing more details on the various stages that make up this rig. 

I hope to work Nick on 17 HB2HB soon. 

Thanks Nick! 

Tuesday, September 13, 2022

Great Technical Info and Tribal Knowledge from GQRP

Thanks to Tony Fishpool G4WIF for sending us this link.  

https://www.gqrp.com/tech.htm

There is a lot of great tech info and Tribal Knowledge on the GQRP page.  This is all related to our discussion of how to set up an electronic workbench or workshop. 

Thanks Tony and thanks to GQRP. 

Monday, September 5, 2022

Why Do Some VFOs Tune More Linearly Than Others?

This has been one of the major complaints about our beloved analog LC VFOs:   The frequency tuning on these circuits is often not linear.  For given amount of VFO frequency dial turn you can get vastly different changes in frequency.  At one end of the tuning range the frequencies are nicely spaced and tuning is easy.  But at the other end of the tuning range all of the frequencies are bunched together.  This is one of the problems that leads some homebrewers to defect to the sad land of "digital VFOs." 

But wait.  It appears that the old designers found a solution to this problem.  Just look at the tuning dial of my HT-37.  The frequencies are all spaced out evenly.  How did they do that? 

I had been thinking that this success may have resulted from Hallicrafters' engineers using the series-tuned Clapp circuit.  Here the main frequency determining element is a series-tuned LC circuit and not the parallel tuned LC circuit that we see in the more commonly used Colpitts circuit.  

But hold on -- how could that be?  The frequency bunching problem that we attributed to the Colpitts circuit must also exist in the Clapp, right?  I went back to SSDRA where there was a good discussion of Colpitts and Clapp VFOs.  The advantage of the Clapp was said to be in its use of a larger value coil which helped minimize the effects of stray inductances.  But there was no mention of the Clapp offering improved linearity in tuning.  

I have in front of me two transceivers:  The Mythbuster uses a 9 MHz Clapp circuit (see below).  The 17-12 rig uses a Colpitts Circuit.  I checked the tuning linearity of both.  Both appeared quite linear in tuning, with no real difference between the two.  

Then I looked at the tuning capacitor in the Mythbuster 17-12 rig.  It came out of an old Hallicrafters transmitter, probably the HT-44.  I looked closely at the stator and the rotor plates.  Both are curved.  I'm guessing that this may yield a more constant change in capacitance for a given movement of the main tuning dial.  

Next I opened up the VFO on the Mythbuster.  (It is the VFO from an old Yaesu FT-101.)  I couldn't see the stators very well but it appears that their shape is different from the square shape we often see in variable capacitors.  Could it be that this variable capacitor was also made to provide linear tuning?  

Back in 2013 Norm Johnson wrote about all this in the Antique Radios.com forum: 

A capacitor that has uniform increase in capacitance with rotation will have the stations at the high end of the band squeezed together. Another type known as the straight-line frequency variable capacitor has, as you might guess, a characteristic that gives even spacing of frequencies with shaft rotation. These were popular in the 1920's but weren't very good for superhets where you needed to have a dual section capacitor that would tune both the RF and local oscillator, and have them track each other properly. The midline variable capacitor is more compatible with a superhet, and easier to make both sections track properly. This is the type that you see in most receivers from the late 1930's to the end of the tube era. They don't have quite the equal spacing between stations across the band that the old straight-line frequency caps had, but they're much better than the variables that change capacitance linearly with rotation.

I wrote an online calculator that helps in the design of the tuning. It shows what frequency range you'll get with a specific type of variable capacitor, including the effects of padder and trimmer capacitors. It also displays a dial scale that shows how the frequencies are lined up accross the dial.
http://electronbunker.ca/eb/BandspreadCalc.html

Steve W6SSP also provided some really good info back in 2013: 

There are three types of open, variable plate caps;
SLC= straight line capacitance where the capacitance varies linearly,
these are the most common and have half-circle plates
SLF= straight line frequency where the plates are tapered to allow
for linear tuning of the frequency
SLW= straight line wavelength, you get the idea...

SLF and SLW caps have oblong plates.

The effect on tuning a receiver can be dramatic. One example is the
Hammarlund SP series of receivers where the ham bands are very
compressed at one end of the tuning range. They used SLC caps
in the VFO. On the other hand rigs like the Kenwood TS-520
and FT-101 series have linear tuning across each band. These use
SLF variable caps. Most old 1920's battery radios used SLW
where stations were identified by their wavelength.
Steve W6SSP

These two variable caps came out of my junkbox.  Both are Eddystones, made in England.  My guess is that the one on the left is SLF.  But could the one on the right (out of an old regen) be SLW?   

The Drake 2-B also has perfectly linear tuning.  I looked at the manual:  "The tuning condenser is of special design..."   I'm guessing that they used an SLF variable capacitor. The 2-B had no need for ganged capacitors -- the "preselector" was tuned via a separate front panel control. 

I looked at the tuning dials on my Hammarlund HQ-100 receiver.   It is fairly linear in its tuning, but not as linear as the HT-37 or the Drake 2-B; on all of the tuning ranges the frequencies seem to spread out a bit at the lower end.  My guess is that Hammarlund used the midline variable described above by Norm Johnson.  The HQ-100 did use a ganged variable cap, with one section tuning the RF amplifier and the other tuning the local oscillator. 

Mythbuster on the bottom.  17-12 rig on the top


Monday, June 6, 2022

SolderSmoke FDIM Interviews: Hans Summers G0UPL Talks about the QDX and His New Balloon Tracker

 

Thanks to Bob Crane W8SX for getting us this wonderful interview with Hans G0UPL.  Its really amazing to hear Hans talk about how many QDX rigs and Baloon Trackers have been sold by QRP Labs, and how quickly they sell.  Really great.  Hans's comments on the realities of the parts shortage was also very interesting. 

Listen here (about 7 minutes):  http://soldersmoke.com/2022 G0UPL.mp3

U4B Balloon Tracker 

Wednesday, June 1, 2022

Marconi the Fascist

For obvious reasons Marconi stories pop up in my news feeds.  This morning an article  from Wales reminded me of a very dark and disheartening aspect of Marconi's life:  his fascism and his participation in the persecution of Jews. 

There have been at least 14 stories in SolderSmoke extolling the technological virtues of Marconi.  I even met his daughter Elettra while in Rome and wrote it up for the blog.  But it is just wrong to sing Marconi's praises while ignoring his fascist involvement. 

His fascism wasn't even separated from his radio work.  He won fascist honors and he won his appointment to Mussolini's  Academy of Italy  because of his radio work.   Take a look at this quote: 


He became President of Mussolini's Academy of Italy -- and it was in that position that he participated in the persecution of Jews.  He was a member of the Fascist Grand Council.

If you have doubts about this, just take a look at the short clip (above) from Marconi's 1937 funeral procession.  Note the fascist salutes, note Mussolini himself marching in the procession. 

The article from Wales: 

Tuesday, May 17, 2022

Tim Hunkin on Prototyping, Welding, and on Being a "Jack of all Trades"


I always like Tim Hunkin's videos, even when they are not directly related to radio electronics.  In this one we learn about his prototyping techniques -- this does seem similar to what many of us do when building rigs.  

I liked his explanation of welding, and of the dangers of the angle grinder (his precautions on this device were similar to those in a recent video by "Spirited Man" Van Neistat). 

Tim's final comment on how in the modern world we seem to have moved away from the notion of having one person skilled in many different areas -- we are now very specialized, so the "Jack of All Trades" is increasingly rare.   That's a shame.  Oh well, we can be Jacks of all Trades in our radio shacks. 

Thanks Tim! 
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column