Maybe, but not necessarily. Some power-line noises can continue in the
rain. Anecdotally, it has been reported to me that insulators that
develop noise tend to not have that noise diminish in the rain. Of
course, noisy devices in neighbors' homes also don't diminish in the
rain, either. If I had 120-Hz noise that didn't change when it got
really wet, I'd not rule out power-line noise, but would give a bit more
thought to what man-made source it could be.
If noise does go away when it gets wet, that usually tells you that it
is outside. Mosture can short out a weak spark or tracking source. More
likely, it tends to make wood increase in size, so old wooden structures
can have loose things tightened up by the rain.
Mike Martin is smarter than I am, so he may have some addition (better)
words of wisdom.
Ed Hare, W1RFI
ARRL - The national association for Amateur Radio
ARRL Laboratory Manager
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Internet: W1RFI@arrl.org
Web: http://www.arrl.org/
Member: IEEE, Standards Association, Electromagnetic Compatibility
Society
Secretary: IEEE, Connecticut Chapter
Secretary: IEEE EMC Society Standards Development Committee
Member: ASC C63 EMC Committee, Chairman: Subcommittee 5, Immunity
Vice Chair: IEEE P1775 BPL EMC Committee
Member: ICES SCC-28 RF Safety
Member: Society of Automotive Engineers EMC/EMR Committee
Board of Directors: QRP Amateur Radio Club International
>-----Original Message-----
>From: Kim Elmore [mailto:cw_de_n5op@sbcglobal.net]
>Sent: Monday, October 11, 2010 8:20 AM
>To: rfi@contesting.com
>Subject: [RFI] POwer line noise (cont)
>
>After a night of rain, we have a foggy morning. I was
>expecting quiet on the bands. but absolutely NOTHING has
>changed! I still have 120 Hz power line noise of S9 + 20 dB on
>40 M in AM mode with 6 kHz bandwidth.
>
>Is this telling me something significant?
>
>73,
>
>Kim Elmore, N5OP
>
>_______________________________________________
>RFI mailing list
>RFI@contesting.com
>http://lists.contesting.com/mailman/listinfo/rfi
>
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|