Hi Don, Very nice job, I've used similar methods to accurately track down power line noise at W3LPL. My power company is very responsive when I give them reliable RFI location information.
I use a Yaesu FT-847 in my vehicle with a short vertical whip antenna to track power line noise on the HF bands. You don't need a large vertical antenna on your vehicle because you're usually looking for strong signals. The FT-847 is particularly effective because it covers all ham bands from 1.8 to 450 MHz, and it has an excellent S-meter and AM detector. I've tried using my Elecraft K-3 but its S-meter and rather poor AM detector are serious impediments to success. For locating individual poles I use a handheld Yaesu FT-817 and a six element handheld 440 MHz Yagi. 73 Frank W3LPL ---- Original message ---- >Date: Fri, 4 Jan 2013 08:08:11 -0500 >From: Don Kirk <[email protected]> >Subject: Topband: Power Line Noise Direction Finding >To: [email protected] > >Hello Topbanders, > >For the past few months I have been plagued by what I suspected was power >line noise on 160 meters, and finally was able to track it down to a power >line pole 0.66 miles from my house and learned a bunch during the process. >While this topic has been covered in the past, I thought some info from my >recent exercise might be useful to others (and a good reminder of what >techniques work). Here is a link to a simple website I created that >contains pictures, oscilloscope screen shots of receiver audio, and links >to video recordings that I made. > >http://sites.google.com/site/powerlinenoise/ > >The factors which really helped locate the noise source were as follows : >1) My 160 meter pennant RX antennas indicated the noise was originating NE >from my house. >2) Ability to hear the noise on 1710 khz on my car radio while driving >around which helped me zero in on a section of power lines (but it was >impossible to zero in on a particular pole). >3) Observing (using oscilloscope screen shot of audio on 160 meters using >radio in AM mode) that noise frequency was 120 hertz which is typical of >power line equipment arcing (arcing each half of the sine wave). >4) Direction finding using VHF AM radio (portable scanner with AM aircraft >band capabilities listening on 136 MHZ) using a portable 4 element >horizontal beam and 20 dB attenuator that I was able to switch in as I got >close to the source. > >Notes : >1) I tried using a portable 160 meter AM radio with portable shielded DF >loop, but I was unable to zero in on the suspect pole (with 100 percent >certainty) using this equipment, and it was not until I used the VHF AM >radio with lots of attenuation that I was able to identify the suspect pole. >2) VHF direction finding beam worked much better when mounted horizontally >(peak and null data made much more sense). >3) I used EZNEC demo to confirm the amount that I need to lengthen the >elements on my two meter beam in order to maintain the proper beam pattern >when used on 136 MHZ. I used alligator clips to lengthen the elements and >this worked out just great (nothing fancy). > >73's >Don (wd8dsb) >_______________________________________________ >Stew Perry Topband Distance Challenge coming on December 29th. _______________________________________________ Stew Perry Topband Distance Challenge coming on December 29th.
