[RFI] Position of noise cancel antenna
w4lde at numail.org
Tue Nov 11 16:42:17 EST 2008
Unfortunately I have had for the past month or so a significant level of
line noise, power company is working on installing new poles and wire
and have not completed the task although it looks like there close to
the finish line. I have tracked the noise on 144Mhz - AM and also
331Mhz - AM using a Yaesu VX-5R and a 3-el on 2 meters plus a 7-el cut
for 440Mhz. The noise is radiating along the lines and seems to be
shifting from the point of origin, one day its pole A and then the next
its pole D.. I attribute this to the work and power imbalances caused
by the crews.
One day its not there and then the next day its back. I have been
keeping a log just in case after their completed and I am not back to
normal S-0 on 20-meters I can help the service crews locate where the
installation' crews were and help track it down to a specific area.
In the mean time I have dragged out my old MFJ-1026, put up a 40 meter
slopper and I am able to reduce the S-9 noise on 40 meters to a S-2
which meets my needs. At times the noise has more than one component or
source so I am constantly needing to look for a new null on the MFJ.
With they correct antenna for a specific freq. the MFJ works quite well.
On 30 meters and 20 meters I can only reduce the noise 4-5 S-units even
with the noise antenna pre-amp turned on and little to no effect with
the preamp off.
At present the slopper is running N to S while the main antenna is
running E to W. Should I try an redirect the slopper and get it more
horizontal as in the main antenna? Would I be better off with more
Any recommendations as to the type of reference antenna and direction or
any additional thoughts you might wish to share will be appreciated
73 de Ron W4LDE
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