Hi Ernie, W8EH
I agree with your diagnosys and this is why I writes to Dave N6CO the following information.
"To find out from where the noise come out you need a MFJ-852 Meter A/C Line Noise Meter visible in the following internet address:
http://www.mfjenterprises.com/Product.php?productid=MFJ-852
This instrument is currently used by the Electricity Power Companies in England."
73" de
i8CVS Domenico
----- Original Message ----- From: "Ernie" w8eh.ernie@gmail.com To: "Dave Larsen PhD" doc@volcano.net Cc: amsat-bb@amsat.org Sent: Saturday, August 03, 2013 4:52 PM Subject: [amsat-bb] Re: Help with 75 mtr Qrn problem
Dave,
I had a similar problem on 80 meters at my QTH. The power company couldn't find it. I finally did. I drove the entire area mobile with my 706, trying different bands. Having 2 meter and 70 cm fox hunt antennas, equipment and attenuators helped me a lot too.
The QRN signal on 80 was very high here, about 40-50 over s9. I finally found it over 6 blocks away. It was a lower 'static' line (neutral) touching a back support line, both ran between the two poles and crossed each other barely touching. The funny thing was, when I measured it the distance between the poles was about a half wave on 80/75. So the 'back guy' was a good half wave antenna on 80. And it was aimed my direction.
My noise would go away when wet or damp and would get stronger when the sun came up and warmed everything and evaporated the moisture.
Keep in mind, generally the noise won't be heard on the higher bands (430 mhz) unless you are less than a couple hundred feet away from the source. You can hear 80 meter noise from power lines over a half mile away. The closer you get to electrical noise, the higher in frequency you can 'usually' hear it.
Once you find it, insist the power company see the before and after on your equipment. My contact here didn't believe that I could hear the noise that far away.
Ernie W8EH
On 8/2/2013 6:23 PM, Dave Larsen PhD wrote: I have 2 dipoles up at 60+ ft - one set running East-West other North South .. From 2.6 to 5 Megs I have a S-7 Qrn lev at 4 Am .. buy noon I have a 10-20 over QRN Lev .. I live on 10 acres and have turned off main power to house and still have QRN .. so not coming from anything in house .. This one has me stumped .. 6 moths ago my Qrn was a S-2 .. waiting for a G6 radio to try and track this down but does anybody else have any idea's ?
Tnx
Dave N6CO