VK2RH ham radio

Category: Components

  • Roll your own valves (tubes)

    A few weeks back – in the post about wartime crystal production – I made a tangential reference to my all time favourite YouTube video – Claude Paillard F2FO distilling down to less than 20 minutes his meticulous work making a triode valve, effectively by hand to create a very cute looking valve wearing blue shorts.

    Hand made triode

    F2FO, radioamateur depuis 1959, montre ici les différentes étapes de la construction d’une lampe triode réalisée par ses soins. Cette lampe a permis d’établir des liaisons avec d’autres radioamateurs situés sur 4 continents.
    Si vous souhaitez en savoir plus, visitez son site web personnel : http://paillard.claude.free.fr

    Watching it again, this time I spent a bit more time looking over the many pages of background information he had posted on his website detailing his research into triodes of the 1920s, the techniques he used and the equipment he used or made to complete this project.

    This prompted me to start a more methodical reading of the documents, and to work through the translations to ensure I understood what he had done. (Google translate is great, but it missed a significant amount.) If you’re vaguely interested in the technology of the earliest days of radio, and have ever wondered how these valves were made, the documents take you on a special journey through the eyes of an explorer with a brilliant workshop and skills to match. His research is comprehensive. By way of exploring how early valves were made he produces a full detailed and illustrated life story of the evolution of valve types and introduces important valve families like the 6L6 and its descendants like the 6V6 and the 807 of the late 1930s. He also takes you on an excursion to discover the history of creating an effective vacuum, critical in the creation of the valve aka the vacuum tube.

    It’s also an enjoyable way to build up a French vocab for the terminology of valve radio gear. Along the way I stumbled across the Electropedia, a brilliant resource for translating technical terms from French to English with a number of other languages included. But some of the terms Claude Paillard uses reflect an earlier era and vocabulary. He talks about the plaque (plate) of a valve rather than l’anode. I’d love to find online versions of the French radio engineering references he cites from the 1920s.

    Edouard Cliquet wrote a number of books explaining radio

    Another plus of this experience is reading the history of radio from the perspective of a country other than Britain or the US. The French version of radio history introduces interesting characters and stories to the familiar names and places. An inspiration behind the work of F2FO is the history of the triode TM (Télégraphie Militaire). A good outline is at Michel Siméon’s website.

    Pratique et théorie de la T.S.F by Paul Berché

    Paul Berché was another prolific author of French radio texts.

  • Grinding quartz and holding a frequency during World War II

    I’m a great fan of the Prelinger Archives which is home to so many items like this video I’ve heard about recently from various ham radio email lists.

    I like how the components of the earliest electronics and wireless were so basic and ‘natural’. Think of hand made capacitors and resistors using traces of graphite on paper. Valves (or tubes) of course were another story but still capable of being ‘homemade‘.

    I love the idea that an accurate, literally rock solid frequency could be achieved using a piece of a very common rock – admittedly a pure piece of quartz cut just so.

    This video details the elaborate and meticulous manufacture of quartz crystals during World War 2 by Reeves Sound Laboratories in 1943.

    Crystals go to War, 1943 – A story in pictures of the preparation and manufacture of quartz crystals for radio communication

    The 41’24” video can also be viewed (free of youtube ads etc) and downloaded via the Prelinger Archives.

    Most of the ‘radio quality’ quartz was mined in Brazil which ceased its neutrality in 1942 and joined the Allies.

    The story of quartz crystals during WWII is told in ‘Crystal Clear‘ by Richard J. Thompson Jr. (Wiley) 2011.

    “Crystal Clear – The Struggle for Reliable Communications Technology in World War II” by Richard J Thompson Jr.

    “In Crystal Clear, Richard Thompson relates the story of the quartz crystal in World War II, from its early days as a curiosity for amateur radio enthusiasts, to its use by the United States Armed Forces. It follows the intrepid group of scientists and engineers from the Office of the Chief Signal Officer of the U.S. Army as they raced to create an effective quartz crystal unit. They had to find a reliable supply of radio-quality quartz; devise methods to reach, mine, and transport the quartz; find a way to manufacture quartz crystal oscillators rapidly; and then solve the puzzling “ageing problem” that plagued the early units. Ultimately, the development of quartz oscillators became the second largest scientific undertaking in World War II after the Manhattan Project.”

    (from the book’s blurb)

    Illustrating the precise angles needed for the AT and BT cuts of a quartz crystal…

    You can read more of the detailed earlier history of the evolution of the US quartz crystal industry at https://ieee-uffc.org/about-us/history/uffc-s-history/a-history-of-the-quartz-crystal-industry-in-the-usa. It tracks how early manufacturers developed techniques for cutting and grinding the natural quartz for the most accurate results.

    Frequency measurements were made by determining the difference between the frequency of the test blank and that of some reference frequency such as a secondary frequency standard consisting of a one MHz crystal unit controlling a frequency generator which developed a set of radio frequencies having integral multiples of 10 kHz. Measurement of the difference frequency, detected by a radio receiver, was a major problem which was solved in various ways. One of the early manufacturers, E. L. Shideler, used the family piano as an interpolation oscillator. More affluent manufacturers could procure an excellent analog frequency meter from General Radio Co. and within a short time David Packard and William Hewlett developed the HP-200 audio oscillator which not only met a need in the quartz crystal industry but also launched the Hewlett-Packard Corporation.

    A History of the Quartz Crystal Industry in the USA
    Proceedings of the 35th Annual Frequency Control Symposium, pp. 3-12, 1981
    Virgil E. Bottom

  • Arnie Coro and the Super Islander

    Looking back over some older email list posts today I came across an interesting exchange of posts on the QRPp list.

    In early August Arnie Coro CO2KK announced latest progress on the ‘Super Islander Version 5 QRP transceiver project’. Key design criteria include using “as much as possible parts that could be recycled from easy to find sources of electronic components” such as toroids from PC boards salvaged from failed compact flourescent globes, and other treasures from broken VCRs, TVs and fax machines.

    Via the short Wikipedia bio of Arnie Coro I discovered a link to more than seven years of transcripts of his weekly radio program ‘DXers UNnlimited’ broadcast by Radio Habana Cuba. Earlier transcripts are here. He also has a blog last updated in June. They’re practical and full of useful ideas.

    One transcript is reproduced on dxzone.com and is an undated description of the project detailing what appears to be the first valve version of the project – I think designed by his friend Pedro, CO7PR. It brings home in a softly stated way the challenges and barriers facing radio enthusiasts in countries which for one reason or another don’t enjoy relatively high wages to afford factory made gear, and who have to be much more resourceful in making do with what they have available to get on the air.

    A rude dismissive comment on the QRPp list prompted a firm but calm response from Arnie.

    “Yes amigos, it is very easy for people having access to the money and the possibility of buying factory built radios or even well designed kits with full instructions and each and every part required… even washers , to just sign a check or complete and electronic transaction that will bring to  their homes a nice piece of equipment…

    But that is not the case for many of us, that do enjoy very much the amateur radio hobby, and think not only about ourselves, but also about those that may benefit from also well designed, easy to assembly and to adjust radios that can be built using locally available parts.

    Try to find even the lowest cost ceramic filter for building a single sideband rig in no less than 130 countries around the world and you will meet with the fact that they are impossible to locate, and the same goes for ferrite and powdered iron toroids, IF transformers, RF power transistors, small relays , RF connectors, resistors and capacitors, not to mention quartz crystals and integrated circuits !”

    SolderSmoke named Arnie ‘Homebrew Hero’ earlier this year.

    Arnie Coro CO2KK – photo by Rodger WQ9E c 2000

    Arnie ended one of his missives to the QRPp list with this plea:

    “Maybe one day the International Amateur Radio Union could sponsor a similar project to help promote amateur radio among young persons that live in poor nations where buying a factory made transceiver may be equal to the full salary of a worker during five years or more !!!”

    I remember that one of the first QRP designs I ever built (back in the late 1970s) was a simple VXO controlled 6 W 20 m CW transceiver that appeared in QST (Dec 1978). It was later suggested as a prototype IARU transceiver as ham aid for developing nations. (This radio certainly worked for me, with a first contact into the US west coast with W6QR from a camp site in Kangaroo Valley!)

    Arnie’s idea appears much more economical and self reliant, drawing on the potential of recyclable components. It’s also a design thought through from a Cuban perspective rather than a first world one.

    You can even hear an interview with Arnie Coro recalling the Bay of Pigs invasion in 1961. [audio].

  • B&W coils

    I was surprised to see that one longtime brand I associate with my earliest days playing around with radio, Barker and Williamson, is still thriving – and even better, still providing the product I associate them most closely with, air wound coils, specifically the Miniductors.

    B&W coil

    There’s a list of the types they have available here. They’re not cheap, but they are convenient. They don’t appear to have a local Australian distributor. They do sell an attractive looking 13-42pF butterfly variable capacitor for US$25.