LF,
It seems i have destroyed the first stage of my LF RX converter, used in
my LF Grabber. I remember the discussion about the need for protecting
the first stage (by 2 antiparallel diodes) of an active E field probe
antenna. There were some statements that the first stage will not be
destroyed but here is an example that this can actually happen. The
converter still works but has lost efficiency by about 20 dB and
suddenly JXN (VLF, 16.4 kHz) is visible on 136.6 kHz in my wideband
window(lower window at
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_LF_DX_Grabber.html
). It seems to be a mixture with DLF (153 kHz -16.4 kHz), tnx DF6NM for
the hint. The active antenna is in 2m distance to my TX antenna that is
at about 10 kV during transmitting.
I will repair the probe, will add some protecting diodes, change the
distance of the RX by 20m. Additionally i'll compare the performance of
the TX antenna as a RX antenna...
73, Stefan/DK7FC
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