It's a beautiful night! At 20:25, I have started up a
straight carrier on 8970.002 Hz (DHO locked). If all stays
well I will leave it on until after sunrise.
An interesting observation on the side: In the first few
minutes, I drove the amp up to 400 mA antenna current. A
little corona became visible near the ends of two of the
three topload wires - it wasn't very bright, not unlike 3rd
magnitude stars when viewed from the ground 10 m below. But
the 9 kHz sound from antenna itself could be heard quite
loudly, which is a potential cause for neighbourhood
trouble.
Then I reduced the drive to 350 mA where the corona
disappeared completely. So did the noise, the antenna became
absolutely quiet! All that was left was a little noise from
the coil in the dustbin on the balcony, and the transformer
indoors. Thus the predominant cause for a squeaking antenna
must be corona. The fact that it can be heard at 9 rather
than 18 kHz demonstrates that the discharge must have an
asymmetric dependence on the voltage polarity.
At the same time, wideband electrical noise on the nearby
LF grabber antenna went down by 20 dB.
BTW If you like you can actually read my VLF frequency
from an alias line on the LF TA grabber: It is created by
the 24th VLF harmonic, intermodulating with DCF 77, thus
appearing on 24 x 8970.002 - 77500 = 137780.048 Hz.
Best regards,
Markus (DF6NM)
