----- Original Message -----
Sent: Saturday, October 04, 2014 8:58
PM
Subject: LF: ZEVS RX ant question, now
success - 60 Hz in Europe
Attempting to resend...
Sent: Saturday, October 04, 2014 1:18 AM
Subject: Re: LF: ZEVS RX ant question, now success - 60 Hz in
Europe
Hi Wolf, Stefan,
yes I also noticed a weak 60 Hz line during my
ELF experiment, and it is there in the accelerated wav files. Here are two
spectrograms with 15.3 mHz bin width:
Unlike Zevs, 60 Hz seems to be more
pronounced during 1855-2055 UT recording, ie our evening when the Atlantic was
still in daylight. It was hardly visible in the morning, 0541-0741
UT.
During the two evening hours, the 60 hz line
drifted up and down by about two pixels, 30 mHz. That frequency
instability may actually be a unique signature which can be used to exclude
local origin, simply by comparing simultaneous traces from two different
receive sites. I think there may even be an online log of
American line frequency history, but couldn't find it on the web
- any hints from the group?
Best 73,
Markus (DF6NM)
Sent: Saturday, October 04, 2014 12:41 AM
Subject: Re: LF: ZEVS RX ant question, now
success
Hi Stefan and all,
you wrote:
Yes,
a good idea. I will try to catch it :-) But how do i know that it is the US
mains instead of a 60 Hz monitor? Is the 60 Hz from the mains more
stable?
I guess the opposite: Similar to our Eu mains frequency, the
US 60 Hz signal "wanders around" very slowly, as the load changes, but in the
long run they also keep the frequency stable, nation-wide. Not sure about the
maximum excursion from the nominal frequency (I lost the notes and screenshots
years ago when a harddisk died) and how many mHz per minute the frequency may
drift. But you can see the weak 60 Hz trace in Renato Romero's ZEVS
spectrogram at
http://www.vlf.it/zevs/zevs.htm
73,
Wolf .