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Showing posts with label radio history. Show all posts
Showing posts with label radio history. Show all posts

Monday, September 27, 2021

Lighthouse Larry's GE Sideband Handbook

 

There is lot of information about early SSB and DSB operations in the GE Sideband Handbook (1961).  Lighthouse Larry is very informative.  Early in the book there is a guide to help homebrewers select intermediate frequencies that will work well in SSB and DSB rigs. 

Here is the book.   Remember, we are dealing with tubes and high voltage here: one hand behind your back.  Volts jolt but mills kill!  



Monday, September 13, 2021

So Where DID the LSB/USB Convention Come From?

-- Bottom line:   I still don't know why ham radio adopted as a convention LSB below 10 MHz and USB above 10 MHz.  There are several theories. but so far there is no convincing explanation in favor of any one of them. And almost all of the people involved are probably Silent Keys by now; this makes it more difficult to gather first-hand information. 

-- I'm not even sure when the convention began to be observed in ham radio. Many of the early SSB books and articles make no mention of it. We don't see it in early ARRL Handbooks. The first mention of it that I found was in the 1965 issue of the ARRL's "Single Sideband for the Radio Amateur" page 8. This article claims that adding a provision for selectable sidebands would "add appreciably to the cost of the equipment. " It went on to say that,  "For this and other reasons there has been a species of standardization on the particular sideband used in the various amateur bands. Nearly all operations in the 3.5 and 7 Mc. phone sub-allocation is on lower sideband, while the upper sideband is used on 14, 21, and 28 Mc."  

-- We know that the informal convention was being followed as early as 1958.  Jim N2EY reports that in 1958, the manual for the Central Electronics 20A shows that LSB was the "sideband most commonly used" on 75, with USB preferred on 20:

-- Some cite a 1959 ITU recommendation on commercial multiplexed radiotelephony as the reason for the convention.  But I don't think this obscure and long-ago ruling explains the convention.  If this were the case, we'd  see follow-up FCC regulation, and at least some discussion of the ITU recommendation in the amateur radio literature.  But we see none of this.  And, as noted above, by 1958 hams were ALREADY -- on their own -- opting to use LSB on 75 and USB on 20.   The 1965 ARRL SSB book refers not to some hard-and-fast rule, but rather to  "a species of standardization" on LSB and SSB.  That ARRL book said nothing of the 1959 ITU recommendation. 

-- There is a widely held belief that this practice originated in the design of a rig that had a 5.2 MHz VFO and a 9 MHz filter.  According to this theory such a rig -- due to sideband inversion -- would produce LSB on 75 meters and USB on 20.  But, as we have demonstrated, this doesn't work, so this theory has to be discounted. 

-- Early SSB activity seems to have been concentrated on 75 meters, and there was a competition for space with AM stations.   SSB operators appear to have used the very upper band edge as their gathering spot.  Using LSB allowed them to operate very close to the upper band edge -- a lot closer than AM stations could go.  This may explain why LSB became the preferred SSB mode on 75.  But how do we explain USB on 20 and above?  That remains a mystery. 

-- It is important to remember that in the early days of SSB, for most hams there were only two important phone bands: 75 meters and 20 meters.  40 meters was CW only until 1952, and even after that was crowded with shortwave broadcast stations.   So a design that allowed for both 75 and 20 was twice as good as a monoband design. 

-- Early on there were designs and parts for phasing rigs.  You could take that ARC-5 VFO at 5 MHz, build a phasing generator around it, and then mix it with a 9 MHz to get on either band.  But with just a simple switch, this kind of rig could operate on USB or LSB on either band.  So the early popularity of this kid of rig does not explain the convention. 

-- There were a lot of surplus 5 MHz ARC-5 VFOs available. There were also FT-243 and FT-241 surplus crystals at both 5 MHz and 9 MHz that could be made into filters.  Later in the 1950s, 9 MHz commercial crystal filters became available.  If you used a 9 MHz filter with a 5 MHz VFO, there would be no sideband inversion in your rig.  If the SSB generator was putting out LSB on 9 MHz, you'd be on LSB on both bands.  So if there was a desire to have LSB on 75, why not just also have LSB on 20? 

-- But if you built a 5.2 MHz filter and a 9 MHz VFO,  you could have LSB on 75 and USB on 20 without having to shift the carrier oscillator frequency.  This would save you the trouble and expense of moving the carrier oscillator/BFO to the other side of the passband.  This desire to economize and simplify may explain why we ended up with LSB on 75 and USB on 20.  But this still begs the question: Why the desire for USB on 20?  

-- Both the manufacturers and the hams wanted there to be sideband standardization.  With monoband rigs, the manufacturers would be able to cut costs by building for only one sideband.  Hams also wanted to cut costs, and they did not want to have to figure out which sideband a station was on when trying to tune him in. 

-- By 1962-1963  Swan and Heathkit were selling mono-band SSB transceivers that used the "conventional" sidebands:  The rigs for 75 and 40 meters were on LSB while the 20 meter rigs were on USB.  There were no provisions for switching to the other sideband. This seems to have reinforced the practice of observing the convention.   (Heath later added sideband switching to the HW monobanders -- in view of the growing observation of the convention, they may have been better off sticking with their original design. Does anyone know why they did this?)  But again, why USB on 20 and above? 

--  In 1963, Swan, by then in Oceanside California, came out with the Swan 240.   Swan used a filter centered at 5174.5 kc. The VFO ran from 8953 kc to 9193 kc on 75 and 20.  The VFO ran from 12222 to 12493 on 40.  This gave the buyer 75 and 40 on LSB, and 20 USB with only one carrier oscillator frequency. (Swan offered a mod that allowed hams to install an additional, switchable carrier oscillator frequency.  I luckily acquired one such modified rig.)  But again, there is an explanation for LSB on 75, but why USB on 20 and above?

This is an important part of ham radio history.   There should be a clear answer.  We need to find it.   If anyone has any good info on this, please let me know.  

Saturday, September 11, 2021

Visiting the Site of Marconi's Wireless Station at Wellfleet, Massachusetts

 

We were in Boston and the Cape Cod area this week.  We stopped off at the Marconi Wireless site at Wellfleet, Mass.   

This is from the National Park Service web site: 

Spanning the Ocean

For Marconi the ‘great thing’ was to transmit wireless signals across the Atlantic. He built stations at Poldhu, England, Glace Bay, Nova Scotia, and South Wellfleet, Massachusetts. At this stage of wireless technology relatively long electromagnetic waves were used as signals. Transmitting great distances, therefore, required great sensitivity of receivers and tremendous power. Originally, huge rings of masts were installed to support the needed antennas. When storms destroyed them, they were replaced by sets of four wooden towers, 210 feet in height. Power requirements were tremendous. Keroseneburning engines produced 2,200 volts. When fed to a Tesla transformer, the voltage was stepped up to 25,000 volts – the energy needed to transmit longwave signals so far. It was from the Glace Bay station that the first successful two-way transatlantic wireless test message was sent on December 17, 1902.
 
A black and white photo of a man and two women standing in an open area facing a building next to a tall circular array of thin antennas.
The original wireless array.

Impacting Lives

January 18, 1903 the first public two-way wireless communication between Europe and America occurred. With elation, communiques from President Theodore Roosevelt and King Edward VII were translated into international Morse code at the South Wellfleet and English stations, respectively, and were broadcast.

Ocean-going vessels quickly adopted Marconi apparatus to receive news broadcasts, and soon ship-to-shore transmittals were a major operation. Business and social messages could be sent for fifty cents a word. The South Wellfleet station became the lead North American facility for this function. The station’s effectiveness was limited however, so broadcasts were made between 10 pm and 2 am when atmospheric conditions were best.

This brought little enthusiasm from local residents, who endured the sounds of the crashing spark from the great three-foot rotor supplied with 30,000 watts. The sound of the spark could be heard four miles downwind from the station. Eventually, the novelty of wireless telegraphy waned. However, the need for communication at sea remained high. Effective communication resulted in numerous sea rescues, culminating in the Carpathia’s wireless-aided rescue of over 700 people from the Titanic in 1912.

For fifteen years the South Wellfleet sparkgap transmitter continued in commercial use. Skilled telegraphers sent out messages at the rate of 17 words a minute, and station CC (Cape Cod) served in effect as the first “Voice of America.”

https://www.nps.gov/caco/learn/historyculture/marconi.htm






Friday, September 3, 2021

1BCG -- 1921 Transatlantic Test and the Upcoming 100th Anniversary


In December 2021 we will reach the 100th Anniversary of the famous Transatlantic Test that marked the first crossing of the Atlantic by radio amateurs.  The video above provides a really excellent description of the momentous event. A few things struck me: 

-- Even then they struggled with amplifiers that wanted to oscillate. 

-- Armstrong should have gotten more credit for the transmitter design.  After all, it was his regenerative system that gave rise to the kind of oscillators that allowed for CW (vice spark) and that formed the basis of the MOPA transmitter that these fellows used. 

-- The info on the Superhet receiver used by Paul Godley in Scotland was really interesting:  It used   "resistance-coupled amplifiers without transformers," similar to what we have today in Farhan's BITX transceivers. 

-- Wow, Harold Beverage himself! And his antenna was used at the Scotland receiving station. 

-- "It was a miracle that no one got mixed up with the high voltage."  Indeed.  

The Antique Wireless Association has built a replica of the 1921 transmitter.  The video below shows it being tested. 
 

The 1BCG website announces that: 

On December 11, 2021 the American Radio Relay League, The Radio Club of America and the Antique Wireless Association will recreate these historic transmissions on 160 meters near the same location that was used in 1921, using a replica transmitter constructed by volunteers at the Antique Wireless Association. This special event is your opportunity to relive a historic moment in amateur radio history.

The operating schedule and frequency for the 1BCG Transatlantic Tests Special Event has not been established.

Additional details will be posted here when they are available.


http://1bcg.org/1BCG/

Wednesday, September 1, 2021

SSB History -- The Tucker Tin 2 (and 3) with a 1961 Recording. Hallicrafters FPM-200 Video by W9RAN


There is so much important SSB history in this video from Bob Nichols, W9RAN.  I liked all of it,  but the on-the-air recording of a 1961 transmission from a Tucker Tin 3 was really amazing.  Check it out. 

Here is the 2014 SolderSmoke blog post about the Tucker Tin 2. You can see the 1961 schematic here: 

As you can see this is a very simple phasing-type SSB rig.  The SSB generator is crystal controlled at the operating frequency.  

Thanks to Bob W9RAN, and thanks to Peter Parker VK3YE for posting about this video on the SolderSmoke Facebook Page. 

 

The Chatham Islands

Wednesday, August 25, 2021

Video: E. Howard Armstrong and Early Radio


This is a really wonderful video. It might seem slow to those accustomed to faster-paced YouTube videos, but the information content is very high -- it contains a lot of pictures I hadn't seen before and audio of Howard Armstrong.  

I never knew that the name of the radio company Zenith was derived from the early callsign "9ZN." 

As a Northern Virginian, I like the reference to NAA Arlington.  

I used to live near Yonkers, N.Y.  I remember Warburton Ave.  What a fine shack young Howard had up in that cupola attic.  

The photo of Armstrong's breadboard was very nice.  My Mythbuster is in good company.

QRPers will get a kick out of the newspaper headline "New Radio Marvel Revealed!"  (They cut the power out from 20kW to 5 watts!) 

Thanks again to Dave Bamford W2DAB for sending me the book about Armstrong, "Man of High Fidelity" by Lawrence Lessing.  

Finally, I remember talking to Bruce Kelley W2ICE at hamfests.   He was a great radio amateur: 

Be sure to check out the Antique Wireless Museum's YouTube Channel.  Lots of good stuff there: 

We have the famous photo of Major Armstrong,
 but this is the first one I've seen of a slightly younger Captain E. Howard Armstrong. 


Sunday, August 22, 2021

Joe Galeski's 1960 "IMP" 3 -Tube Filter SSB Transmitter, and the Spirit of SSB Homebrew

Here is another important bit of SSB history.  In  May 1960, Joe Galeski W4IMP published an article in QST describing his super-simple SSB transmitter.  While Tony Vitale's "Cheap and Easy" rig was a phasing design, Joe came up with a filter rig.  He built USB filter at 5775 kc.  With it, he ran a VXO at around 8525 kc. This put him on 20 meter USB. 

Here is the QST article: http://marc.retronik.fr/AmateurRadio/SSB/A_3_tubes_filter_rig_%28SSB%29_%5BQST_1960_5p%5D.pdf 

In discussing how to put this rig on other bands, Joe got the sideband inversion question exactly right: 


Thank you Joe!  

Joe even provides an comment that seems to capture an important element of the homebrew SSB ethos.  Joe homebrewed his filter, but he mentioned the possibility of using a store-bought filter: 


That's the spirit Joe!  

Along the same lines, Jim Musgrove wrote in Electric Radio: 


Having built Lew McCoy's Mate for the Mighty Midget receiver (which also used just three tubes), I can't help thinking that an IMP-ish transmitter would be an excellent complement to the Mate for the Mighty Midget.  

Jim Musgrove K5BZH knew Joe Galeski and wrote about him in the January 1992 issue of Electric Radio.  Jim wrote that Joe was an optometrist by profession. When OE1FF wanted to know the cost of building an IMP, Joe Galeski boxed up the original and sent it to him.  FB Joe. 

In December 1961 Joe Galeski published a QST article describing a transistorized version of the IMP -- this rig ran on 15 meters.  K5BZH wrote that Joe later published an article about a small, solid-state transceiver,  appropriately called "The Shrimp." 

Monday, July 26, 2021

QST Repeatedly Got Sideband Inversion Wrong

It kind of pains me to do this. These articles are from a long time ago, and the author is an esteemed  Silent Key,  but the myth about the origins of the USB/LSB convention is still out there, and as a homebrewer of SSB gear I feel obligated to point out these examples of the error that that myth is based on.   

Last Friday, Pete WB9FLW and I were talking about homebrewing SSB rigs.  I recommended a series of QST articles by Doug DeMaw.  "Beginner's Bench:  The Principles and Building of SSB Gear" started in QST in September 1985. There were at least five parts -- it continued until January 1986. (Links to the series appear below.) I hadn't looked at these articles in years, but when I did, a big mistake jumped right out at me:  In the first installment, on page 19, Doug  makes the same mistake that he made in his Design Notebook:

"Now comes the conversion section of our SSB generator.  We must move (heterodyne) the 9-MHz SSB signal to 3.75-4.0 MHz. Our balanced mixer works just as it does in a receiver. That is, we inject the mixer with two frequencies (9 MHz and 5 MHz) to produce a sum or a difference output frequency (9 - 5 = 4 MHz, or 9 +5 = 14 MHz) If we are to generate 75 meter SSB energy, we must chose the difference frequency. We could build an 20-meter SSB transmitter by selecting the sum of the mixer frequencies. The RF amplifiers and filter (FL2) that follow would then have to be designed for 14-MHz operation.  In fact, many early two-band homemade SSB transmitters were built for for 75 and 20 meters in order to use this convenient frequency arrangement.  The use of upper sideband on 20 meters and lower sideband on 75 meters may be the result of this frequency arrangement (the sidebands become inverted when switching from the difference to the sum frequency.) " 

Those last two sentences are incorrect.  They repeat the "Myth," or the "Urban Legend" about the origins of the LSB/USB convention.  Contrary to what many hams now believe, with 9 MHz filter and a 5.2 MHz BFO it takes more than just switching from sum frequency to difference frequency to invert one of the sidebands. 

There are two conditions needed for sideband inversion to take place:  

1) You have to be taking the difference product (DeMaw got that right) 

2) The unmodulated (VFO or LO) signal must be larger than the modulated signal. (DeMaw and the ARRL obviously missed that part.  Repeatedly.) 

This is another way of stating the simple, accurate and useful Hallas Rule:  Sideband inversion only occurs when you are subtracting the signal with modulation FROM the signal without modulation. 

For DeMaw's claim to be correct, one of the SSB signals going into the balanced mixer would have to invert, and the other would have to not invert.  Let's see if that happens: He has the sideband signal being generated at 9 MHz and the VFO running around 5 MHz. 

9 - 5 = 4  But we are not subtracting the modulated signal FROM the unmodulated signal.  SO NO INVERSION

9 + 5 = 14   We are not subtracting at all.  SO NO INVERSION.  

Doug's convenient frequency scheme WOULD work if he'd just switch the frequencies of the filter and the VFO.  With a sideband generator on 5.2 MHz and a VFO around 9 MHz you do get the happy 75  LSB, 20 USB arrangement without the need to switch the carrier oscillator/BFO frequency.   That is what happened in the Swan 240, and that is what I have in my Mythbuster rig. I am listening to both 75 LSB and 20 USB without changing the carrier oscillator/BFO frequency.  My filter/BFO/product detector is set up for USB.   With this arrangement the 75 meter LSB signals DO invert, and the 20 meter USB meter signals do not, so both are able to make use of my USB BFO/product detector without shifting the BFO frequency. 

This error shows up again in DeMaw's the May 1989 QST article "A Four Stage 75-meter SSB Superhet" (reprinted in the ARRL's QRP Classics book).  Here he writes: 

"Should you want to cover both the 75- and 20-meter bands you can build a 20-meter version of FL-1 and band switch the two filters. As with the 75 meter only version, an IF of 9.0 MHz (Y1) is required. With this arrangement the 20 meter band will tune backwards from the 75 meter band, but upper- and lower-sideband reception will occur, as required, without changing the BFO frequency (Y2). This two band scheme with a 5-MHz VFO is an old one!"   NOTE: FL1 is the bandpass filter, not the IF filter.  

Doug's mistakes in this area may simply be due to the fact that he was more of a CW guy.  And this is something that is quite easy to confuse:  9 and 5 will get you to 75 and 20, but you have to make sure the VFO is at 9 if you want to make use of sideband inversion and avoid having to shift the BFO/ carrier oscillator.   I've made this mistake myself: 

In October 1993 I wrote to DeMaw about his Four Stage 75 meter SSB Superhet.  I think I was looking for details on how to put it on 20 meters.  As I recall, Doug wrote back telling me to just pick 20 meter values for the input bandpass filter.  Had I done so, I would have discovered that  -- for the reasons cited above -- this just wouldn't have worked on 20.  His BFO and filter were set up to receive LSB signals. That's fine for the incoming 75 meter LSB signals.  But on 20 -- contrary to DeMaw's thinking -- there would be NO sideband inversion. I'd be trying to listen to 20 meter USB signals with a receiver set up for 20 meter LSB.  

Did anyone else notice these errors.  Were there ever errata notices in QST on this?  

This is a reminder that you should take all technical articles and schematics with a grain of salt.  Many contain errors. We are all human, and this is a complicated subject with lots of details. 








Thursday, July 1, 2021

Summer Reading for Homebrewers: Frank Jones and the FMLA by Michael Hopkins AB5L (SK)

 
Frank Jones W6AJF (SK)

I read these stories when they were first coming out and I really liked them.  Here are all the FMLA episodes.  Don't try to read them all in one sitting.  Spread them out.  Savor them.  Think about the message that Frank was sending us.  

All of the FMLA episodes:  https://tomfhome.files.wordpress.com/2019/12/frank_and_the_fmla.pdf

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

Related articles, books and links: 

Frank's obit: https://www.pressdemocrat.com/article/news/frank-jones/

Frank's book "5 Meter Telephony": https://w5jgv.com/downloads/5-Meter%20Radiotelephony%20by%20Frank%20Jones.pdf 

Frank's 1937 Antenna Handbook: http://rfcec.com/RFCEC/Section-3%20-%20Fundamentals%20of%20RF%20Communication-Electronics/23%20-%20RADIO%20ENGINEERING%20DATA/1937%20-%20Jones%20Antenna%20Handbook%20(By%20Frank%20C.%20Jones).pdf

About the author, Michael Hopkins AB5L: https://www.rantechnology.com/index.cfm?key=view_resource&TransKey=615604E8-9DAA-40A3-9E48-4160806D893D&CategoryID=8E884CE4-9CED-4957-872B-5EBDB058D540&Small=1

Michael Hopkins AB5L (SK) 

Thanks to Dave Wilcox K8WPE for reminding us of all this, and for sending us the link to the FMLA archive. 

Viva el FMLA!   Viva el CBLA!  Vivan! 

The World's Largest Heathkit Collection (Video)


And this was apparently AFTER they relocated and organized things a bit. 

I have my eye on those QF-1s.  Someone stop me before it's too late.

I also spotted a Globe VFO Deluxe.  

Thursday, June 17, 2021

The Stubborn Myth about USB and LSB

It  has been repeated so often and for so long that many of us have come to believe it.  I myself believed it for a while.   Like many myths, it has a ring of truth to it.  And it is a simple, convenient explanation for a complex question: 

Why do ham single sideband operators use LSB below 10 MHz, but USB above 10 MHz? 

Here is the standard (but WRONG) answer: 

In the early days of SSB, hams discovered that with a 9 MHz SSB generator and a VFO running around 5.2 MHz, they could easily reach both 75 meters and 20 meters (True). And because of sideband inversion, a 9 MHz LSB signal would emerge from the mixer as an LSB signal (True), while the 20 meter signal would emerge -- because of sideband inversion -- as a USB signal (FALSE!)  That sideband inversion for the 20 meter signal explains, they claim,  the LSB/USB convention we use to this day. 

Why this explanation is wrong: 

There is a very simple rule to determine if sideband inversion is taking place:  If you are subtracting the signal with the modulation FROM the signal without the modulation (the LO or VFO) you will have sideband inversion.  If not, you will NOT have sideband inversion.

So, you just have to ask yourself:   For either 20 or 75 are we SUBTRACTNG the Modulated signal (9 MHz) from the unmodulated signal (5.2 MHz)? 

For 75 meters we have:   9 MHz - 5.2 MHz =  3.8 MHz    NO.  We are not subtracting the modulated signal from the unmodulated signal.  There will NOT be sideband inversion. 

For 20 meters we have 9 MHz + 5.2 MHz = 14.2 MHz.     NO.  No subtraction here.  No sideband inversion.   

So it is just arithmetically impossible for there to be the kind of happy, easy, and convenient  USB/LSB situation described so persistently by the myth. 

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

We discussed this several times on the podcast and in the blog: 

https://soldersmoke.blogspot.com/2015/05/sideband-inversion.html

https://soldersmoke.blogspot.com/2012/05/usblsb-urban-legend-debunked.html 

This myth shows up all over the place: 

We see the myth here: 

http://n4trb.com/AmateurRadio/Why%20The%20Sideband%20Convention%20-%20formatted.pdf

Here the web site owner warns that this is "highly controversial."  Really?  Arithmetic? 

http://9m2ar.com/lsb7.htm

The myth is very old.   Here is a clip from a 1966 issue of "73" magazine: 

https://worldradiohistory.com/Archive-DX/73-magazine/73-magazine-1966/73-magazine-01-january-1966.pdf

Finally, to my disappointment, I found the myth being circulated by the ARRL, in the 2002 ARRL Handbook page 12.3: 


The fact that the Handbook attributed this to a desire to "reduce circuit complexity" by not including a sideband switch should have set off alarms.  We are talking about hams who built their own SSB rigs, usually phasing rigs.  A sideband switch would not have added significant circuit complexity. I think they could have handled it. 

It is interesting that earlier ARRL Handbooks do not repeat this myth.  I found no sign of it in Handbooks from 1947, 1959, 1963, 1973, and 1980.  And I found no sign of it in several editions of that great ARRL book "Single Sideband for the Radio Amateur." 

For my next homebrew rig, I will build a rig that DOES do what the myth promises.  I will have the SSB generator running on 5.2 MHz USB.  The VFO (out of an old FT-101) will be running around 9 MHz.  So for 75 meters we WILL be subtracting the signal with the modulation from the signal without the modulation:   9 MHz - 5.2 MHz = 3.8 MHz.   There will be inversion.  This 75 meter signal will be LSB.   For 20 we will just add the 5.2 MHz USB signal to the 9 MHz  VFO.  There will be no inversion.  We will have a USB signal on 20.   I'm thinking of calling this new rig "The Legend." Or perhaps, "The Mythbuster." 

Thursday, June 3, 2021

Remastered! The Secret Life of Radio -- With Updated Comments from Tim Hunkin


Thanks to Stephen 2E0FXZ for alerting us to this important video. 
We first posted about the original many years ago.  We were delighted to learn that they have remastered the video and added 10 minutes of retrospective commentary from Tim Hunkin.  

Here are some of my reactions after watching the updated version:
-- The Marconi videos were amazing.   I actually met Elettra at a diplomatic reception in Rome.  
-- I was pleased to learn that Marconi was trying to "call up" Mars.  FB OM. 
-- My son Billy and I sat in that same Royal Institution auditorium where, 100 years before, Oliver Lodge had demonstrated spark gap technology. 
-- Tim's comment on the connection to supernatural beliefs was right on the mark.  We found out that the house we lived in in London was a center for occult beliefs and practices. 
-- Those square lantern batteries brought back fond childhood memories. My first power supplies.
-- The Rexophone -- used by Rex. 
-- Very cool of Tim to homebrew a coherer.  Extra credit for that.
-- One of the capacitors looks familiar.  EF Johnson? 
-- I agree with Tim -- crystal radios are a must-build for true radio hams.  And do it with galena and a cats whisker. 
-- Finally, the RCA ad introduces a term we might want to surreptitiously enter into the Enhanced SSB lexicon:  That "Golden Throat" sound.   


Tuesday, March 16, 2021

A REALLY Cheap Receiving Rig


Wow, lots of ingenuity in this 1921 receiver.

-- Has anyone actually made a diode out of a light bulb in the way described? 

-- The antenna coupler on the table leg is not much different from the tuner that I have attached to the wall of my car port. 

-- Note that when our hero finishes the receiver, he is able to pick up signals from Mars!  FB OM. 

Who will be the first to recreate this 1921 receiver? 


Monday, March 15, 2021

Aladdin's Lamp == The Vacuum Tube (aka The Thermatron) (Video)


After our posting of the video about 1957 transistor production, our friend Peter O'Connell VK2EMU asked for some equal time for vacuum tubes.  He sent me this 1940 Western Electric video.  It is quite interesting. 

-- I like the Aladdin's lamp metaphor.  When I was out in the Azores I thought of my homebrew 17 meter DSB rig as my "magic carpet." 

-- Lowell Thomas was brought in to narrate.  His voice sounds a lot more natural than that used to narrate the transistor film. 

-- To explain the effectiveness of transcontinental telephony with vacuum tube repeaters, they compared the system that of a relay of "hog callers" claiming that it would take 100,000 hog callers to carry a signal from New York to San Francisco.  So perhaps this could be a rival to db?   100,000 hc? 

-- Arlington to Paris 1915 caught my eye -- Arlington Va. is right down the road. 

-- The film of Edison in his lab was good to see.  And note the importance of his lab notebooks. 

-- The explanation of thermionic emission was quite good.  But of course too much credit was given to Lee DeForest. 

-- The breathless description of the amazing uses of tube technology was for me a reminder of how recent this technology is.  My father started as New York City cop in the 1950s.  He always referred to his police car as a "radio car." 

Hey, are any radio amateurs out there using one of those big water-cooled tubes?  If not, why not? 

Saturday, March 13, 2021

Making Transistors in 1957


Thanks to Thomas K4SWL for alerting us to this video -- he had it on his excellent SWLing Post blog

Many things crossed my mind as I watched this video: 

-- Pocket protectors!  Pete recently noted that this was a common fashion accessory among electronic techs and engineers back in the day. 

-- HP test gear. 

-- "Extreme cleanliness" that doesn't seem quite so clean.  

-- 550 transistors per hour.  Now we have upwards of 50 billion on a single chip. 

-- The Germanium salami that Pete mentioned in our last podcast. 

-- Hints of Silicon's impending replacement of Germanium. 

-- A transistor factory in Spring City, Pa. that "hums with excitement" (seemed kind of sleepy). 

-- The 1957 assumption that Philco transistors would be in the first orbiting satellite.  Then came Sputnik.

-- The transistor that moves like a "Gulliver through Lilliputian lands."  

-- Our voices or accents seem to have changed, at least the voice used in products like this.  No one talks that way today. 

-- As I watched, I tried to remember if Pete's CK722 was made by these folks.   But no, that was a Raytheon product.   Here is a nice short description of the early days of the CK722:   https://en.wikipedia.org/wiki/CK722   We need to learn more about the hobbyist Carl Todd.

Tuesday, January 26, 2021

SolderSmoke Podcast #228


Soldersmoke Podcast #228 is available: 

Of course, no travel.  But vaccines are here so maybe soon we can leave our shacks.

In the meantime:

I’ve been playing chess against AI bots on chess.com.

Netflix recommendation:  The Bureau.   From France. A review from NPR: 

https://www.npr.org/2020/06/22/881642358/addictively-suspenseful-thriller-series-the-bureau-will-keep-you-on-edge

A reading from "Conquering the Electron."  Germanium vs. Silicon.

Bill’s Bench:

The KLH Model Twenty-one II.  Acoustical Suspension.  First receiver WITH A PILLOW!  Bad speaker? Blown AF amp finals.  Hot heat sink.  VBE Multiplier. Desitin.

Tony Fishpool’s recommended LM386 boards.  10 for 11 bucks.  Nice.  They work.  Pictured in the Amazon ad at the upper right of the SolderSmoke blog page.

Putting a digital display on the Lafayette HA-600A

Test gear trouble.  My Radio Shack multimeter getting flaky.  I many need something better.  Auto ranging? My beloved Maplin AF generator died – will have to fix. I need that thing.  Probably a bad chip.  Good thing they are socketed.

I almost forgot about SKN!  But I remembered and I made one contact with the HT-37 and Drake 2-B.    

Pete’s Bench:

Presentation to RSGB on Homebrew.

TenTek Troubleshoot.

Swan 240?  Looking nice.

SDR adventures.

MAILBAG

Bill N8ET sent me some really nice Showa 9 MHz 8 pole crystal filters. 

Kevin AA7YQ Smoke jumper!  Building a hybrid SDR.HDR rig.  Launched blog. FB

Nick M0NTV working on similar HDR/SDR project.  Great video.

Grayson KJ7UM Hollow State Design – Launched a new blog.  Very FB!

Thomas K4SWL of SWL Post blog.  Kearsarge Mountain Transmission system.  And recent events.

Peter VK2EMU Poetry.  CW poetry.

Pete WB9FLW looking at DSB rigs…

Drew N7DA  Feels not like a real ham because he hasn’t built a quad from bamboo. Which type of landscape bamboo is best for antennas?

Ryan Flowers of MiscDotGeek.Com blog is also watching the Tally Ho YouTube videos of Leo Sampson. Wants to put a WSPR beacon on the Tally Ho. 

Joe KF5OWY  Working with diode ring mixers, trying to see the mixer action on his ‘scope. 1 and -1!

Jim AB9CN sent a cool idea about how to do a 20/17 Moxon.

Roy GM4VKI – I thanked him for his article in SPRAT about putting a 2n3904 on the output of an NE602 10P mod.  Brilliant.

Roger Hayward Told him that I really liked his Dad’s recent web site updates.

Farhan – Jokingly cursed me for showing him the Oscillodyne regen of Hugo Gernsback and Jean Shepherd.  “Now I will have to build this!”


Tuesday, January 19, 2021

"The Transistor" 1953 Video from The Bell System


Interesting video. 

-- Good discussion of the transition from tubes.  

-- Go Arlington, Virginia! 

-- Nice video of Bardeen, Brattain and Shockley at work (Shockley does seem a bit off to the side). 

Sunday, January 17, 2021

STOP. LISTEN. Shep on Building a Shortwave Receiver


Oh man, how could I have possibly missed this one?  Perhaps I didn't, but even if this one has been on the blog before, it is so good that it is worth repeating.  

Shep really captures the frustrations and joys of a teenage radio builder.  I could really identify with this.  It all reminded me of my heartbreaking effort to build the Herring Aid 5 receiver. 

So much cool stuff in this 1963 recording: 

-- The wonderful smell of radio service shops. 
-- The terrible shirt and tie choices of radio service guys. 
-- The truly dire consequences of mistakes in published schematic diagrams. 
-- The AGONY of not being able to get a homebrew radio to work. 
-- The JOY when you finally do get it to work. Shep's "whole life changed" when that happened. 
-- Hugo Gernsback, Lee DeForest and "unscientific scientists."

As the YouTube video plays, they show several covers of old Short Wave Craft magazines. At one point they show some homebrew phone rigs.  I think they look like my wooden box BITX rigs.  And the front panels are clearly Juliano Blue.  TRGHS. 

Here is the 1933 Oscillodyne article that launched Shep's effort: 


EXCELSIOR! 

Monday, January 11, 2021

KLH Model Twenty-One II -- Is My Speaker Dried Out?

A few years back Rogier PA1ZZ very kindly sent me a box of electronics parts.  Included was an FM table-top radio with a nice walnut case.  Thanks Rogier! 

I hadn't looked at the receiver in years, but this week I dusted it off and looked it up on the internet.  Turns out that it is kind of famous.  It was produced by the KLH company.  The K stood for Henry Kloss, one of the giants of Hi-Fi audio gear.  Henry appears in the picture below. 

I got the receiver working, but it sounds awful.  It sounds much better with an external speaker, which is disappointing because the internal speaker was the main attraction of this receiver. It even has a little badge on the front panel trumpeting(!) its "Acoustic Suspension Loudspeaker."

I'm wondering if the problem is in fact the speaker.  The cone looks intact, but it seems very dried out.  It has been more than 50 years...  What do you guys think?  Picture above.  Any other suggestions on what to do with this thing, or how to make it sound better? 

Some KLH history:  

https://klhaudio.com/history

https://antiqueradio.org/KLHModelTwentyOne21FMRadio.htm

KLH receiver with pillow

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