Dear Henny,
my QTH is about 400 m from a railway line,
and I regularly saw their 16.667 Hz power frequency and several
ELF harmonics. The E-fields are relatively strong as the lines normally do
not carry a grounded top wire for lightning protection. The "modulation" could be caused by some
switching activity.
Another origin might be a
controlled rectifier on the 50 Hz mains, which could be triggered
at a subharmonic frequency.
Best regards,
Markus, DF6NM
Dear Markus,
I have even thougth
that this "67Hz" in reality might have been 66.667 Hz, and this would open
other ideas, such as mixer products between 50 Hz and 16,667 Hz
etc.
HW?
73 Ha-Jo, DJ1ZB
----- Original Message -----
Sent: Wednesday, March 04, 2009 7:43
PM
Subject: LF: capture 67hz.jpg
Hi,Lf
capture unid signal 67hz,but who
?
henny pa3cpm
best
73s