Our Hackaday team is distributed all over the world, but keep in touch easily through the magic of the Internet. Many of us have amateur radio call signs, so with a little effort and expense, we can do the same thing over radio waves. A hundred years ago, this seemed almost unthinkable, because amateurs could only use HF frequencies that were considered unusable at the time.
Therefore, in December 1921, a group of American radio amateurs gathered in a field in Greenwich, Connecticut, trying to cross the Atlantic Ocean. One hundred years later, their 1.3 MHz transmitter using the call sign 1BCG seemed to be a weird low frequency, but their success in ensuring reception in Ardrossan, Scotland proved that intercontinental communication on higher frequencies is a practical proposal.A century later, a group from the Antique Wireless Association Bringing the copied launcher to life Recreate the event.
Nowadays, free-running oscillators are rarely seen in radio transmitters, but at that time their single-tube Colpitts oscillators using UV-204 transmitter tubes were considered a stable source. Three UV-204 connected in parallel are used to power the 1KW power amplifier, which in turn provides the ground balance of multiple radial lines for the Marconi-style T antenna design. The replica was originally built for an event in 1996 and replaced the currently unavailable UV-204 with a similar 204A tube. Even so, it will be difficult to find a hundred-year-old tube by 2021, so they can only collect a working example for PA.
All in all, this is a very interesting project, and we hope that as the anniversary day approaches, we will hear more news. If we can get the details of the transmission, we will share it with you and let us see if we can traverse the same distance in noisier conditions in 2021.
In order to demonstrate the advanced nature of this transmitter in 1921, take a look at the Alexanderson alternator, its mechanical contemporary.