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 again....
Laurence KL7L We2XPQ etc
> Date: Mon, 30 Mar 2015 18:00:44 -0400
> From:
[email protected]> To:
[email protected]> Subject: Re: LF: LF tonite
>
> Markus,
>
> > 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.
>
> John, W1TAG
