VLF: 300 mA on 4470 Hz, 67 km band

[DK7FC <selberdenken@posteo.de>]

Hi VLF,

It took much longer than expected. Maybe 2/3 of the winter season is over now. Time to finally go the next step down to DC, another episode of the series "300 mA on..." :-)

Since 22:15 UTC a 300 mA carrier is running on 4470.1 Hz. A wavelength of  67114 m :-) The ERP is about 25 uW.
For the next few hours the tree will show the signal over the 3.5 km distance: http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
The carrier will run until 8 UTC (except the safety circuit trips dur to strong rain).
The new coil arrangement consists out of 6 (5 + 1/3) stacked buckets. Here a photo showing the arrangement for 5170 Hz (4 + 1/3): http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/coil5170Hz.jpg Now there is just one more bucket in the stack.

Before starting the next experiment on 970 Hz (probably next week), there are a few days now for a short message on the band.
Will it be possible to transfer a message over to Alex, on the 1990 km landpath? It is less than 30 wavelengths distance :-)
Also it would be a first detection and new lowest frequency for SQ5BPF in 920 km distance...

With some optimism i think 2 characters can be possible in 4 nights:

f = 4470.100000 Hz
Start time: 18.JAN.2018  16:00:00 UTC
Symbol period: 60 s
Characters: 2
CRC bits: 16
Coding 16K23A (NEW)
Duration: 13h20min [hh:mm]
Antenna current: 300 mA

73, Stefan