Topband: Local Noise Environment

[Ken Brown]

Pete,

With the antennas you have I don't think you are going to gain much more 
information about the location of the noise source(s) than you have 
gained already. If you could arrange to rotate the loop you might get a 
more accurate azimuth bearing on the predominant noise source. However 
since most of the interference sources are connected to the power grid 
(or ARE the power grid) they tend not to appear as "point sources" but 
rather radiate from the miles of power grid, being slightly stronger 
closer to the place where the arcing or other noise generation action is 
occuring. Since the power grid is a much less efficient transmission 
line at higher frequencies, the noise source will act more and more like 
a point source as you listen to it at higher frequencies. And you can 
make portable antenna with a real good directional pattern at higher 
frequencies too. So, it is common practice (even though 160 meters is 
what you are interested in) to use a portable VHF AM receiver and a two 
or three element yagi to DF on the noise source. Finding a VHF receiver 
that functions in AM mode used to be difficult. Almost the only options 
were VHF air band handhelds, which had not other purpose for you, and 
really expensive all mode scanners. These days though, you can buy a two 
meter or multiband handheld that has AM receive function too.

Good luck, DE N6KB