Hi VLF
This weekend could fix the QRM
problem with the VLF E-probe. There was a ground loop at the 1pps from
GPS
The ground of the GPS (and PC
via USB) was routed to the audio transformer at the VLF signal side,
not soundard side
So, the noise was going up by
the VLF cable to the probe and caused a 20dB noise rise in MF/LF in the
nearby MiniWhip
The VLF espectrogram has got
clearer, but still contaminated. Specially at night, probably due to
street led lights in the area
I'm using a separate first Fet
at the probe, connected by aprox 15m TV coax. Would it be better to use
twisted pair or
keep all the preamp up, close to
the probe ?
73 de
Luis
EA5DOM
