Hi Daniele, VLF,
Congrats to your successful VLF reception! :-) If you compare your
received signal to that of Renato Romero, it is not much weaker. Since
Renatos Antenna is excellent, i assume the low S/N is caused either by
local QRN in Italy or simply by the propagation. If i remember
correctly, in my 3rd experiment, Renatos reception was one of the best
of all! So maybe we should/could learn something about the VLF
propagation between Germany and Italy, above the alps. I think the lower
S/N is not (only) due to the presence of the alps! All this is very
interesting :-)
There is still no reception in Italy on 6470 Hz (46 km band), sadly. It
is just because of my mistake with the generator :-( At least 2 hours of
TX time was lost :-( Ok, never mind...
Maybe 6470 Hz is much more suitable to cross the alps. We will check
this in the next experiment i would say? :-)
6470 Hz has many advantages i think, at least if the mains hum at a
given RX location is about at equal or less strength than on 8970 Hz. I
have observed that the (day)time of low QRN is much longer there.
Another question is how the S/N as a function of time behaves. Attached
you see a capture of my 'wideband' grabber window of the last sunday
(including those nerving horizontal local QRM lines). You can see the
frequency region of the maximum sferics level is changing with daytime.
On 8970 Hz it is 'dark' from 7...12 UTC but on 6470 Hz it is 'dark' from
7...17 UTC.
Maybe some VLF receiving OMs can record their 'wideband' window on their
own location and we can share the results. This makes it easyer the
compare the situation of various locations :-) And we could discuss
about the best time for a transmission either on 33 km or on 46 km to
reach a given location.
Daniele, can you tell me your call and locator? I want to set up a list
of the successful VLF receptions :-)
73, Stefan/DK7FC
wideband03OKT2010.jpg
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