I've got a wideband short burst noise. It is very short - maybe 1/20th
of a second. It affects everything from roughly 0 to 20 mhz. It is
weaker on the higher frequencies and dies out around 20 mhz. I'm
getting it at random intervals and a range of strengths. Sometimes there
are 5 in a second and sometimes it takes 2-3 minutes to see one.
Typically it is 20-30 db over my noise level (3 mhz - 8 mhz - below that
the noise level is stronger). It doesn't sound like lightning.
Lightning lasts longer, whereas this is more of a blip noise. Could
it be an arcing loose wire?
I tested shaking the antenna to see if there is a loose connection. No
luck.
I tested some traffic lights nearby as well.
Screenshots from my QS1R:
3.8 - 5.6 Mhz
You can see how much higher the peak noise level is (the grey line that
is 20 db) over my regular noise level. In the spectrum history, you can
see a blue and green horizontal line that crosses the entire band. This
is how it regularly looks (by contrast the faint blue line on the bottom
is not the regular look).
http://www.campusactivism.org/images/pulse1.jpg
Another 3.8-5.6 mhz
http://www.campusactivism.org/images/pulse2.jpg
This shows three closely spaced pulses.
A weaker version of the pulse around 7-9 mhz. I turned up the
sensitivity of the spectrum history so that it could be seen. Again you
can see how the pulse's peak noise level is a lot higher than the
regular noise (20 db+)
http://www.campusactivism.org/images/pulse-8mhz.jpg
2-4mhz
A weak version of the pulse at this range. It can be stronger.
(You can also see vertical lines - I think I've got a touch lamp putting
out inteference, but it is very mild compared to this pulse).
http://www.campusactivism.org/images/pulse-3mhz-mild.jpg
Any ideas? Are battery chargers this random?
Thanks,
Aaron
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
| 
