VLF: VLF QRM free window becomes smaller?

[Stefan Schäfer <schaefer@hst.tu-darmstadt.de>]

Dear LF,

Taking a look on Markus' VLF grabber, it seems, the time window with a minimum 
QRN becomes smaller in the last weeks(see the picture). Has anyone experience 
(Paul?) if this is a daily accident or a tendency when going to the summer? 
What will be in one month?

BTW, my 600W PA almost works; the amperemeter (1A full range) is now inserted 
into the coil and is calibrated; i built up a narrow band active E field 
antenna for the dreamers band (2x BF862, 2 band pass filters, BW abt 500Hz, 
preamp noise 20dB above soundcard noise, preamp + VLF noise 40dB above 
soundcard noise, decoupling AF transformer) that will give my new VLF grabber 
in Heidelberg :-)

Things are going on and new records will have to be done :-)

Best 73, Stefan/DK7FC

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