continuous wave telegraphy in 1929

This is a magnificent replica of an amateur transmitter from the late 1920’s.  It electronically manufactures a signal (by what’s called an ‘oscillator’ circuit) which is interrupted by a Morse code key.  This is ‘continuous wave’ transmission, which is different from the mechanical method of signal generation just going into eclipse in the same decade.  To make a signal by machine, you’d spin a disc-shaped armature in a magnetic field — a dynamo, really, and use your key to interrupt this.  It sounded like a jamming signal, and it splattered widely across the band.  CW, by contrast, was a narrow, tidy way of transmitting.  This was important because the spectrum was crowded beyond capacity.

QRM, or unintentional interference, in most cities was simply intolerable.  Noise from raucous spark sets was even creeping into the telephone.  Boston operators complained of being pushed out by experimenters, research workers, long waver and short wavers, ‘500 cyclers’ and ’25 cyclers,’ wireless phone owners, and worst of all, those wretched “squeak boxers”—owners of the old and splattery spark coil sets.  There was also a thing called “ICW,” for interrupted continuous wave, much like what you see here, only it got its plate voltage (a plate is one of the glowing bits inside the vacuum tube) from an ordinary spark coil.  It was cheap, effective, and electrically noisy.  Los Angeles complained of being shut down by 10:30 each night because of the thousands of spark-coil variants ranged across the neighborhoods.  It wasn’t just the number of signals that offended, it was the primitive tuning.  (Notice how hard it is to keep this set stable.  The two coils on the breadboard here were positioned relatively to each other with care: this was a tuning method called ‘loose coupling’.)  We were all still sloppy enough (or lazy enough) with this particular art that many of us hadn’t even gotten down to 200 meters, where the government wanted us, as late as 1921.  Cities like Springfield, Massachusetts, and San Francisco desperately set up evening rotas of when different types of transmission—spark, c.w., and also radiotelephone, in all their variations—were allowed to operate.  Slick operators were beginning to control their frequency with crystal circuits, but that was a new technique, for later.

The code in this superb demonstration says, VVV (a lot of times, which is a standard test signal) TEST TUNED NOT TUNED (hence ‘TNT’, which means ‘tuned plate, not tuned grid’), TX DE (thanks from) KJ4RGH (his call sign) 73 (an old railroad telegraphy best wishes).

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phone patching

 

Phone-patching was a hip new skill late in the 1960’s.   You saw it a lot on “Hawaii 5-0.”  Hams liked doing it for the technical cachet, and they also liked it for how it streamlined health-and-welfare communication in time of emergency.  It frightened public utilities a lot (which tells you about the number of people involved in amateur radio at the time).  Patching radios to the telephone system was ultimately a good enough thing, finally, that it forced changes in law.  North Carolina, Nebraska, and Oklahoma utilities commissions attacked in court savagely, carrying on a line of legal wrangling that had gone on since the Carterphone case in 1968, the opening battle of the phone companies’ war on customer-owned attachments.  The FCC sided with hams, to many people’s surprise.  Phone patching in principle was made legitimate by January of 1969, in most areas of the country.   Floods of manuals appeared right away, that explained interface specs, and showed how to counterfeit phone company equipment.  An example of this was a much-copied project to make a dynamic VU meter out of a Calectro voltmeter that would act just like the Western Electric standard ones.  Commercial components sprang into existence almost as quickly.  This is the Heathkit version, the ubiquitous ‘hybrid phone patch’, of which a couple variations exist.  Hybrid and Phone Patch are redundant terms.  The ‘hybrid’ part means a telephone circuit that interfaces with radio.  This is an analogue type, that requires no more power than that which comes from the radio and phone circuits; there are digital ones now, that typically require power of their own.

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more public-service boy-geniuses in 1939

There are some great ham history blogs out there, and many have found this gem already.  It’s a short, one of many, by Pete Smith, publicity man for MGM and father of the film’s technical advisor, Douglas Smith.  He takes up the cause of young people’s technical sophistication and enthusiasm for public service.  He’s justified in doing so, for homebrew stations like this one did impressive work in disaster-relief and rescue missions.  They wouldn’t have said ‘broadcasting’; they’d have said ‘transmitting’.  And hams didn’t say ‘Mayday’, as a rule; it was more likely the in-house standard, ‘QRRR’.  Communications for 5,000 miles was routine by 1939; 15,000? well, that’s still a stretch for a lot of us.  Morse Code operators were all using a more efficient ‘continuous wave’ technique than they’d had 20 years before (which you can hear here when young sir tunes across the band); likewise the ‘phone operators, who had largely abandoned the old AM way of modulating carrier waves for a sleeker ‘single-sideband’ way.  What does the code say in this soundtrack?  ‘NO LUCK STAND BY NO LUCK STAND BY AR K’.  (AR, sent together, as one letter, means that’s all the message; K means ‘over’.)  Then, ‘STILL SEARCHING WX BAD AR K’.  (WX is weather.)  Then, ‘WX WORSE NO SIGN OF PLANE AR K’.  Then, ‘OUT OF STORM PLANE FOUND’.  And finally, ‘PLANE LOCATION LONG 73 WIII LAT 41 NIII OUT OF GASFALA’.  That’s how I copy it, anyway.  By the way, radio operators in airplanes, and tanks in WWII, used keys strapped to their knees.  Know who else used them?  Truck drivers, in the 1970’s.  There’s some trivia for you.

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potency finds andy hardy

Won’t make the obvious parallel here, in this beautiful scene involving hip adolescents and their befuddled elder.  This is Mickey Rooney declaring (and not for the only time in his movies) the power of technically-empowered youth culture, ‘all over the world’.  Kids were one of the big demographic groups in amateur radio early in the century.  Here, Youth elides with the public service ethic, another powerful strand in hams’ self-understanding.  There were formal and informal traffic nets always listening for messages that needed delivering.  The government allowed licenses to transmit on short waves precisely because amateur radio had been enshrined in successive legislation as a service, for emergency backup of public communications infrastructure.  The licenses were a good idea, too, because the equipment was high-powered, and in the 1930’s usually homemade.  See the heavy loading coil on the back of that transmitter?  Notice the two-gang switch the kid uses, and how gingerly he handles it?  Operating these rigs was not a trivial skill.  Nor was avoiding government and broadcast interference.  The technical advice behind this clip was good.  W8XCR (Michigan, or thereabouts) and VE3AVS (Ontario) are exactly the right formats for callsigns.  (One of these is currently in use, as a matter of fact.)  ‘CQ’ is used differently these days, but ’73’ still means ‘best wishes’ and ‘DX’ still refers to long-distance contact.  ‘Ham’ is probably old rail telegrapher slang for poor operator.  Amateurs were using the term on the air at the very beginning of the century.

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Filed under the 1930's