Dear Group,
Many thanks to all for their reports of the Op32 transmissions last night,
to Mike for the summary, Terry for the signal strength table and Gary for
his comments and grabber service, and Markus and Graham for their
technical support.
The first transmission was completed at 0032 and the last (19th) at 1025.
There was a delay of 82 s between transmissions. The carrier was
generated by an AD9851 synthesiser clocked by an Oscilloquartz 8663
10 MHz DOCXO which was purchased from "Zhou" in Hong Kong for less than
what a bottle of cheap Scotch would cost, and calibrated against WWV on
10 MHz. An Arduino Uno programmed the 9851 to generate a carrier on
137.555 x 16 kHz and its output was divided by 16 by a cmos 4020 to
improve the resolution and frequency accuracy. The Uno also keyed the
carrier according to the op32 code that was copied directly from an email
from DF6NM. The keyed carrier, a messy 3v p/p square wave, drove 2/3
modules of a Decca amp running at 60 volts 12 amps to yield 3-1/2 amps
of RF which was coupled via 1.6mH of 2mm Litz to a 100m wire at about
12m average height.
The relative signal strengths are useful and I hope to take advantage of
this to compare antennas.
Our local sunrise/set times today are 0734/2332. The summer solstice TA
path may have opened before 0000 utc and had lasted until at least 0546.
I'll give another try again tonight starting 2300 utc.
73 & tnx agn!
Joe VO1na
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