VK2RH ham radio

Category: Military

  • AMR100

    A few weeks ago at the ARNSW Dural site I was talking with Mark Blackmore about the classic radios incorporated into the VK2WI broadcast building. He showed me some beautiful Collins receivers and some Racal sets. Also occupying a position on the equipment rack was a very shiny Kingsley AR7, the famously unauthorised copy of the National HRO receiver produced to supply the Australian Army and the RAAF during the second world war. (I later found a detailed description of the story behind the restoration of what I believe is this actual radio model at Ray Robinson’s website http://www.tuberadio.com/robinson/museum/AR7/)

    Mark looks after disposal sales for the ARNSW and he had tales of beautiful radios that he had inspected over the years that had been stored in less than ideal conditions. His advice in a nutshell – At the very least just wrap the radio up in a large plastic garbage bag!

    This sent a guilty shudder down my spine as I remembered a couple of radios I had acquired a very long time ago that had lived in various storage sheds and cupboards over the decades. But it also prompted me to have a proper look at them over the next week.

    Back in the late 1980s I had bought what I thought was an AR7 from a ham in western Sydney. It also had a complete set of plugin coil boxes. I’m ashamed to confess that since buying it I had never once really examined it to check out its condition. I had downloaded copies of the schematic and the operation manual and even the series of articles from Amateur Radio magazine detailing the various modifications many VK hams made to their AR7s in the 1950s and 60s, but I obviously hadn’t gone further. Even more obviously to me now, I hadn’t even read the first few pages of the manual. If I had I might have realised that I had one too many coil boxes!

    As soon as I started a new web search into what I thought was my AR7 I realised there were some important differences. While it shared the distinctive HRO style dial, my radio had a different front panel and layout of controls. It was nothing like the shiny stainless steel I could see everywhere. In fact the best indication of what the original finish might have been was in a patch where the boiler plate identification of the radio would have been had it not been removed for some reason. The coil boxes looked quite different as well with small charts under yellowing plastic rather than engraved in the faceplate.

    The front panel of my AMR100 looking like it’s been neglected and crying out for some TLC. 

    Thanks to some excellent websites about military radios, it didn’t take long to discover the actual identity of my receiver.

    Dave Prince VK4KDP via the Royal Signals website https://www.royalsignals.org.uk/photos/vk4kdp.htm confirms the radio I have was in fact made by AWA and was probably painted an attractive green. It’s an AMR100. AMR stands for American receiver as they were made for the US Signals Corps. 

    On his own page at https://www.qsl.net/vk4kdp/army.html you can also see a very attractive version of how my radio should appear.
    Note the AWA logo on the US Signal Corps boiler plate, and the green front panel.

    Apparently the AMR100 Receiver was manufactured by AWA in Sydney under licence from National. I’ve read elsewhere that the US Signal Corps in the South West Pacific were having difficulties obtaining HROs from the US and AWA offered to supply them in a form of a reverse lend-lease arrangement.

    Dave VK4KDP describes the AMR-100 as “a Single Signal type covering 480 kHz to 26 MHz with 6 plug-in coil boxes”.

    Armed with this information I was able to locate two detailed operating manuals for the AMR 100 (the ‘table top’ model) and the AMR101 (the rack mounted version) on Ray Robinson’s encyclopedic site at http://www.tuberadio.com/robinson/Manuals/

    http://www.tuberadio.com/robinson/Manuals/AMR100.pdf – a scan of the manual for the desktop model – AMR100 Receiver Type C13500. Ray Robinson refers to it also as US Signal Corps SC-CD-136-43.

    http://www.tuberadio.com/robinson/Manuals/AMR101.pdf – which is a version of the manual for the AMR101 Receiver Type C13500R retyped by John Kidd.

    I also located a scan of the original AMR101 manual at https://bama.edebris.com/download/awa/amr101/amr101. 

    My particular radio includes the same team of valves, two 6U7G RF stages, a 6J8G mixer, a 6J5G oscillator, two 6U7G IF stages, a 6G8G multi-tasking as detector, AVC and AF amplifier, a 6J5 BFO and a 6V6G as AF output.

    The inside of the AMR100 showing added output transformer on top LHS hiding the power supply mod on LHS and missing crystal on RHS

    Once I had a closer look inside the radio it was apparent that a few modifications had been made to the receiver. Where I imagine the 6J5 BFO was originally located – based on markings on the painted chassis – is now occupied by a 5Y3GT which looks like part of an added power supply. The BFO is re-located on a bracket installed beneath the chassis using a metal 6J5 valve. 

    I suspect the 455 kHz crystal has been removed. I have to check whether an FT243 style crystal might fit. It may need some kind of adaptor. 

    Underneath the chassis of the AMR100 showing the general condition of components and wiring. The black metal 6J5 valve for the BFO can be seen on the lower LHS near the BFO inductor.

    Once tidied up the chassis is remarkably clean, top and bottom. Some of the valves bulbs have come loose from their bases. All the valve screens are present and seem okay. 

    The was a shot of the AMR100 chassis after it was removed from its case and before any cleaning

    Overall the condition of the wiring is probably the main cause for concern. The rubber covering is now brittle and much has broken away from the wire. It looks as if it will all need to be replaced. I expect all the paper capacitors and electrolytic capacitors will need to be replaced.

    A closer view under the chassis of the AMR100 showing the condition of the wiring and the vintage and condition of the components

    If I don’t keep the 240 VAC power supply modification I will need to find or build a separate power supply capable of delivering about 270 VDC at 75 mA and 6.3 V at about 3 A. That shouldn’t be too difficult. 

    I suppose the first stage of assessing what to do next (and even whether) to restore the receiver is to check the continuity of all the inductors.

    After removing the speaker output transformer the power supply modification can be seen with the 5Y3GT valve where the 6J5GT BFO valve was originally installed. The tag strip of resistors above the transformer are for setting the various ranges of the front panel meter.

  • Australian Code Breakers

    On Wednesday evening I went along to a talk at a nearby library by David Dufty about his recent book ‘The Secret Code-Breakers of Central Bureau – How Australia’s signals intelligence network helped win the Pacific War’ published last year by Scribe.

    The Secret Code-Breakers of Central Bureau by David Dufty

    It’s a great story that does uncover previously unacknowledged contributions. Dufty’s interest was sparked by a newspaper mention of Australian wartime code-breaking on Anzac Day 2012. His interest triggered a comprehensive research trail.

    It’s a great read with a solid bibliography. He interviewed about twenty people who worked on breaking the Japanese codes. From a standing start, the operation grew to involve over 4,300 Australians – a venture, Dufty says,  it’s hard to imagine us being able to mount as readily today.

    He mentioned many of the characters from Australia’s early radio history, including Mrs Mac, Florence MacKenzie, who trained thousands of women morse operators who in turn were used to train many Australian servicemen.

    He also mentioned Eric Nave who was responsible for breaking Japan’s Naval codes. Nave as a young naval cadet had spent years in Japan learning the language and culture of the country.

    The character with the best nickname would have to be Keith ‘Zero’ Falconer. He was the country’s top interceptor of Japanese Kana coded messages. He got the nickname from his colleagues as every single day of Kana code training in Melbourne he would score zero errors in the test. Japanese hams can still be heard conversing in this code on the bands today.

    Japanese Kana or Wabun morse code

    The character who stands out from David Dufty’s talk on Wednesday evening is Stan or Pappy Clark. Apparently, prior to enlistment, his work was scripting radio serials for children. The mention of the magic word radio was enough to catch the eye of people recruiting for radio intelligence work, and it turned out to be a fortunate selection for Australia.

    Stan Clark used his talents to develop a comprehensive knowledge of the Japanese communication networks and was able to analyse the dynamic ebb and flow of their radio traffic. Even if we weren’t able to decode every message the broad overview – which Dufty interpreted as the ‘metadata’ of the enemy’s radio communication – of this traffic analysis played a crucial role in determining the allied strategy of the war and effectively saved thousands of allied and enemy lives. Macarthur’s famous island hopping strategy was directly informed by this intelligence. One of the special things about Wednesday night was that unknown to Dufty until the end of his talk, Clark’s grandson and family were in the audience.

  • 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

  • Hidden heroes

    The BBC have just broadcast and put on YouTube an excellent hour long documentary about two people whose wartime work is credited with shortening the war and saving millions of lives. Yet because of the cold war and the climate of secrecy, credit came late or not at all.

    UPDATE: The YouTube video has been blocked by the BBC on copyright grounds. Another version with slightly dodgy audio may be available here.

    ‘Code-Breakers: Bletchley Park’s Lost Heroes‘ details the work of young mathematician Bill Tutte who broke the German’s top-secret Lorenz code and Post Office engineer Tommy Flowers who built the first electronic computer ever – to replace ‘Heath Robinson’, the mechanical device used to process the code-breaking.

    Bill Tutte and Tommy Flowers were both ‘scholarship boys’ who benefitted from the best educational and research opportunities available to their generation. Earlier conflicts may not have been able to discover and develop such talents. (And it’s questionable whether comparable educational opportunity is available today.)

    It’s hinted towards the end of the program that the extended secrecy about their achievements is connected to the assumption that the Soviets continued to use the captured German Lorenz system into the 1950s. You can only imagine Tommy Flowers’ frustration, biting his tongue every time someone referred to ENIAC as the first computer!

    You have to marvel at the beautiful minds of these two men – dealing with complex matrices and patterns and the logic associated with understanding them – without the tools we take for granted today. One of my favourite scenes is Bill Tutte at his desk with a hand drawn grid on a large sheet of paper tracking the pattern of the characters in the coded messages.

    This is a very well organised and presented documentary.

  • Winnie the war winner

    The other day I noticed a very interesting photo on a fellow Australian ham blogger, Peter Mark’s site. The blog entry was titled a “Radio nerd’s tour of Canberra“. The first photo is described as ‘a transceiver with a nifty antenna tuner’. But the instant I saw it I sensed there was slightly more to it.

    Winnie the war-winner seen in the Australian War Memorial in Canberra. It was named after British wartime Prime Minister, Winston Churchill.

    The fact that it was built on a beaten up old kerosene can prompted me to google “Winnie the war winner” and the results confirmed Peter’s photo is of this most famous piece of Australian ham homebrew ingenuity. Max (Joe) Loveless’ skill to be precise. The photo prompted me to find out the story of this iconic wireless set that’s an inspiration to a generation of Australian radio hams proud of their traditions of ‘making-do’.

    The wikipedia entry on the Battle of Timor gives detailed historical and military background to this little radio’s moment of fame in April 1942.

    As a result of British intrigue Australian troops were sent to Portuguese East Timor to disrupt any Japanese invasion on Australia’s northern doorstep. By April the 2/2nd Independent Company had been fighting a guerilla campaign for four months. Many were ill and they were low on supplies, and had had no contact with Australia since February.

    For weeks a team had been trying to build a transmitter from salvaged parts from damaged radio gear. Before the war Max Loveless was a radio amateur in Hobart with the call 7ML. He became a Signaller with “Sparrowforce” on the Dutch part of Timor with the Australian Infantry Forces (AIF).

    Report on Winnie the war winner in the Melbourne Argus for 1 Jan 1943 – page 12

    Bill Marien reported the story in the Melbourne Argus of 1st January 1943:

    “Force Intact. Still Fighting. Badly Need Boots, Money, Quinine, Tommygun, Ammunition.”

    This was the first official message received in Australia from the lost AIF commandos of Portuguese Timor who, for 59 days after the Japanese landing on the island, had been written off as missing or dead.

    The signal came to Darwin on the night of April 19. It was transmitted by “Winnie the War Winner,” a crazy contraption built from scraps of wire and tin, and pieces of long discarded radio sets.

    When the commandos showed me the incredible Winnie recently, it was easy to recapture the scene of that night of April 19.

    In the thin air of a Timor mountain hideout, 4 bearded, haggard Australians were working by the smoking, stinking light of a pig-fat flare. Three of them watched anxiously as the fourth thumbed a Morse key. Weak batteries sent the dots and dashes of the morse dimly across the Arafura Sea to the Northern Territory of Australia. The tension was something physical as the operator strained his ears for a reply. At last a reply came.”

    The AIF commando force which had been in Portuguese Timor were joined by other Australians from Dutch Timor including two signalmen, Cpl John Sargeant, of Bonshaw, NSW, and Lance-Cpl John Donovan, of Lindfield, NSW. Under leadership of Capt George Parker, of Earlwood, NSW, they joined Sigs Max (Joe) Loveless, of Hobart, and K. Richards, of Victoria, both of the original commando force.

    “On March 8 the 4 men got to work — Loveless just out of sick bed and Sargeant just recovered from malaria. Three days later a Dutch sergeant, exhausted, stumbled in. He had carried what he thought to be a transmitter-receiver 40 miles through some of the roughest country in the world. It was an ordinary commercial medium-wave receiving set – and out of order.

    CORPORAL WENT SCROUNGING

    Loveless, whose knowledge made him No 1 man of the team, thought he could build a one-valve transmitter from parts of this set and of another small and weak set. He planned a circuit, and all the commandos were asked to be on the lookout for anything that might serve as a radio part.

    Cpl Donovan went scrounging at Attamboa, on the north coast, to see what he could salvage, while his companions recovered an abandoned army set. The parts of the 3 sets were unsoldered, and a bamboo used to catch all the melted solder for re-use. Loveless had carefully preserved 2 small batteries, but they needed recharging. A generator was taken from an abandoned 10-year old car and rigged to a series of wooden wheels, which a native was persuaded to turn. The set was complete on March 26.

    It would not work!

    Three of the team who helped Max Loveless build Winnie the war winner re-enact transmissions from a hill in East Timor – Signaller Keith Richards, Corporal John Donovan and Lieutenant Jack Sergeant. Photo by Damien Parer.

    The only tools available were a tomahawk, pliers, and screw-driver. They had no test equipment to determine the set’s frequency. The coils were wound on pieces of bamboo.

    On March 28 Donovan returned from Attamboa – laden like a treasure ship. He had the power pack from a Dutch transmitter, 2 aerial tuning condensers, 60ft of aerial wire in short lengths, and a receiving set. Next day the men had to move all their precious gear, for the Japanese were getting too close.

    Loveless got to work on a second transmitter twice as big as the first, and built it into a 4-gallon kerosene tin. A battery charger was recovered from enemy-held territory. To get it 14 commandos went through the Japanese lines to the old Australian headquarters at Villa Maria. There, within 100 yards of Japanese sentries, protected only by the dark, they dug up the charger which had been buried when the headquarters were evacuated.

    HEARD DARWIN WAS SAFE

    On April 10 the signallers heard Darwin on the receiver, and knew then that Darwin was still in Australian hands. But their second transmitter was also a failure.

    Loveless had another idea, but he needed more batteries. Four were found. Then the petrol ran out and the charger could not be kept running. So they raided the Japanese lines and carried off tins of kerosene. Finally the charger was started on kerosene and run on diesel oil.

    With batteries at full strength they signalled Darwin on April 18, but got no reply. They did not know that their message had been picked up on the Australian mainland and passed on to Darwin, that all transmitting stations had been warned to keep off the air and listen to Timor the following night.

    You can get a good sense of the story from this video of the documentary ‘The Men of Timor’ filmed in Timor by Damien Parer in late September 1943. You can see a reconstruction of the building of the radio about 3’16″ in from the start.

    On the 19th April they heard Darwin but their batteries failed again.

    On the night of April 20 they again got Darwin. But Darwin was suspicious; demanded proof of their identity. So questions and answers like these were rushed across the Arafura Sea:

    “Do you know Bill Jones?”— “Yes, he’s with us.”

    “What rank, and answer immediately?”— “Captain.”

    “Is he there? Bring him to the transmitter. . . . What’s your wife’s name, Bill?”— “Joan.”

    “What’s the street number of your home?”

    Once they provided the correct answers, help was on its way.

    I found the newspaper report on the National Library of Australia’s brilliant Trove, where digital versions of many Australian newspapers have been put online courtesy of crowd-sourced editors across the global internet. Truly astounding!

  • Monitoring Odyssey Dawn

    One of the most memorable DX programs was Radio Nederland’s Media Network presented by the energetic and innovative Jonathan Marks. Both the program and the presenter live on in different guises.

    I remember being astounded to hear intercepted military signals from the early hours of the Falklands War being broadcast on the program. Long before crowdsourcing or the internet, Jonathan Marks had a network of highly skilled shortwave enthusiasts and gave them a destination – a tape recorder linked 24/7 to a phone number – where they could leave recordings they had made along with relevant details like time, frequency and identifying callsigns etc. From memory he had sounds of commands being issued by the Argentine Navy to the Belgrano.

    After almost 20 years on air the last Media Network was broadcast in 2000. The program morphed into a weblog in the northern spring of 2003 as war broke out in Iraq.
    I was reminded of Jonathan Marks’ ingenuity by reports this week of another radio enthusiast based in Holland and how his monitoring activities revealed a US Psyops broadcast as part of the current ‘Odyssey Dawn’ operation in Libya. It was heard on 6877kHz at 0900Z Sunday 20 March.

    In fact Jonathan Marks may have been one of the sources of this latest story! It appeared on his Critical Distance blog the day before.

    Now in place of Media Network’s phone and cassette recordings, we have blogs, twitter and audioboo! And a torrent of information.

    The Milcom Monitoring Post blog is pulling material together including mp3 clips. But the action and spots are moving very fast. The most appropriate tools appears to be twitter feeds. The source of the psyops recording is @FMCNL. Other monitoring tweets come from @MilcomMP and @QSLRptMT, occasionally using hashtags such as #odysseydawn or #libya.

    An AV-8B Harrier jump jet returns to USS Kearsarge for fuel and ammunition resupply while conducting air strikes in support of Joint Task Force Odyssey Dawn, March 20, 2011. (USMC/Flickr)

    @cencio4 David Cenciotti is an aviation writer and he’s published comprehensively detailed daily ‘debriefings’ of Operation Odyssey Dawn. His writing is clear and military acronyms are de-coded and explained.  The posts on his blog reveal an deeply informed understanding of strategy and a profound knowledge of the aviation industry. His analysis shows how even in the heat of battle there’s some high powered marketing going on!

    Here are some of the frequencies that were being monitored in the early stages of the campaign:
    4196.0 Naval Military style CWC tracking net USB (American English accents). AGI (3/21 @ 2150 UTC). Early on in Operation Odyssey Dawn that was used as a NATO AWACS tracking net USB: Callsign Magic ##/NATO ##
    5725.0 UK Royal Navy CWC-style net USB.
    6688.0 French Strategic Air Force Net – Commandement Des Forces Aériennes Stratégiques (CFAS) USB: Callsign Capitol
    6712.0 French Air Force Commandement De La Force Aérienne De Projection (CFAP) USB: Callsign: Circus Verte
    6733.0 RAF TASCOMM YL weather traffic to Solex 11 a Sentry AEW1 with TAF weather for LCRA RAF
    Akrotiri. QSYed to 9019.0 and 9031.0 kHz USB
    6761.0 USAF Global refueling Operations USB
    6877.0 USAF Psyop transmissions against Libyan Navy + jamming
    9019.0 UK RAF TASCOMM USB TAF weather traffic.
    9031.0 UK RAF TASCOMM USB Operational Messages + TAF weather traffic
    10315.0 DHN 66 NATO Geilenkirchen GER E-3 AWACS/Magic to DHN66 Link USB
    12311.0 French Air Force Centre De Conduite Des Opérations Aériennes (CCOA) USB: Callsign Veilleur/AWACS callsign Cyrano.
    16160.0 French Air Force up with voice and RATT on 16160 kHz USB.
    Libyan GMMRA HF ALE network was still active as of 3/21/2011 on 5368.0 6884.0 8200.0 9375.0 10125.0 10404.0.

    Seems like a good time to sign up for and account with www.globaltuners.com to get my radio ears a little closer to the action. If you follow any of the twitter accounts mentioned above you will have no shortage of up to the minute details of air (and radio) traffic to follow.