We get these here too - most of the dots and dashes appear at
repetitive times every day - related to (mostly!) power meter "Turtles"
in peoples meters which inject signals back to the local substation across the
110/240/7.5Kw transformers - it used to be horrid at 137kHZ - and I
managed to get the electrical utility to revert back a manual reading meter at
home- and then installed a whole house RF filter ( 2 x 220A) on
incoming supply which helped a little more -
I still get
the interference but its a lot better, that and choking the incoming
Cable tv cable outside in the roadside podium with a large "J" ferrite
with 15T - that helped clear up a load of VLF noise too - Cant fix the
fenceless dog interference yet... :-(
Unless its Aliens
Laurence KL7L We2XPQ etc
> Date: Mon, 30 Mar 2015 18:00:44 -0400
> To: [email protected]
Re: LF: LF tonite
> > Wonder what
the little dash below Stefan's "F" was... possibly local QRM
> > from
some MFSK PLC system? We sometimes seem to find a number of
unexplained scattered dashes on North American QRSS spectrograms.
> I watched the entire band for a while this afternoon, and homed in on
> the 136.552 kHz frequency range below, after seeing some "dash"
> activity. Interesting.