1BCG recording (Transatlantic Test anniversary in Dec 2021)

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Phil Erickson

Jan 3, 2022, 9:19:30 AMJan 3
to Unknown
Hi all,

  Soldersmoke's blog has a post today with the recording I made just after 2300 UTC on 2021-12-11 of 1BCG's replica transmitter sending their 100th Transatlantic Test Anniversary commemorative signal on 160 meters:

  Links there lead you as well to the 1BCG page with details of their replica transmitter.  I was fortunate to catch it on the very first transmission when everything went well, before their RF choke broke down and somewhat scrambled their ambitions of repeating it every 15 minutes.  

  Gear = simple 80/40/20 fan dipole from grid FN42dk here in Massachusetts, feeding a KiwiSDR.

  You might enjoy listening to the linked WAV file to hear what a transmitter of the day sounded like.  Lots of 'whooping'.  Pete N6QW guessed that there was a huge amount of ripple on the DC causing that to happen, as was typical of the era.  The spectrogram, from when they were tuning up, is entertaining - also notice how 'wide' the signal was in a local/narrowband sense, hence the chirping.

Phil W1PJE

Phil Erickson

Ward Silver

Jan 4, 2022, 1:58:44 PMJan 4
to hamsci
Phil - thanks!  This is so cool!  Sounds like forty years ago tuning in a station using some really old or lashed together gear.  I worked a few like that in the 70s.  One type of chirp went up ("whoop") and one type of chirp went down ("droop").

The "chowpy chow-pit" could come from poor voltage regulation in the power supply or changing capacitance in the tubes with current that changes the loading on the oscillator circuit.  It's a little like the Miller effect that multiplies the effective capacitance of a transistor's base-emitter or gate-source junction as the device begins to conduct current.  Ripple is what creates the "hummy" or "buzzy" sound.

The Antique Wireless Association sponsors the Bruce Kelley 1929 QSO Party (https://www.antiquewireless.org/homepage/bk-qso-party-details/) and this rig would fit right in!  A great night to hear all kinds of "interesting" signals.

73, Ward N0AX

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