[SCCC] Effectiveness of MFJ-1026 Noise Filter??

Paul Kube K6PO at outlook.com
Tue Apr 2 23:23:08 EDT 2019


Mark, re:



Noise antenna is the critical piece to the puzzle. I'm surprised to hear a horizontal antenna works but in my situation that didn't happen…  All man-made noise is vertically polarized.


I wonder what your take is on these statements from W8JI’s “Radio Noise” page https://www.w8ji.com/noise.htm:



  *   Noise arriving from the ionosphere is randomly polarized. It arrives at whatever polarization the ionosphere happens to favor at the moment. It has the same ratio of electric to magnetic fields (also called field impedance) as a "good" signal.



  *   Sources within a few wavelengths of the antenna combine and produce a randomly polarized noise. Local noise generally has no particularly dominant field. Very local noise, in the nearfield of the antenna, can either be electric or magnetic field dominant.



  *   Noises arriving from groundwave sources some distance from the antenna are vertically polarized. This relatively fixed polarization occurs because the earth "filters out" horizontal components.



73, Paul K6PO



________________________________
From: SCCC <sccc-bounces at contesting.com> on behalf of Mark Schoonover <mark at ka6wke.net>
Sent: Tuesday, April 2, 2019 4:48:04 PM
To: Steve
Cc: SCCC
Subject: Re: [SCCC] Effectiveness of MFJ-1026 Noise Filter??

Steve,

Noise antenna is the critical piece to the puzzle. I'm surprised to hear a
horizontal antenna works but in my situation that didn't happen. What I
ended up having for a noise antenna was winding about 50' of wire
hellically on an 8' crappy fishing pole. All man-made noise is vertically
polarized.

Next up is tuning the thing. What I do is set the noise antenna gain to 0
then adjust the main antenna gain so there's about S4-5 noise level.
Remember the dial number. Set the Antenna gain to 0. Do the same process
with the noise antenna. If you can't reach the same signal strength as the
main antenna you need to make your noise antenna larger. Once you have the
same S reading on both antennas then it's time for phasing. Start with that
knob all the way counter-clockwise then slowly sweep to fully clockwise.
The dips can be rather narrow so go slow. If no noticeable dip or the noise
level increases push the phase button and slowly turn counter-clockwise.
You should find the sweet spot. What I do after that is to rock the main
and noise antenna gain to get a deeper null.

There's also a button for high and low frequencies give that a try too no
matter what frequency you're using.

Good luck! It's a process to figure out but once you know how to do this
any new noise source can easily be removed.

73! Mark KA6WKE

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On Tue, Apr 2, 2019, 15:17 Steve <k0xp at k0xp.com> wrote:

> Anybody actually have experience with the MFJ-1026 "Noise-Cancelling
> Filter", specifically whether it's really effective at cancelling
> plasma TV noise (at least, that's what I think my intermittent noise
> is; I'm not about to go next door and ask the nayboors to turn their
> TV off and on in this HOANazified area just to confirm 8-O )?? Is
> there a better-such filter? Needs to go between my FT-991A at 100W
> output and an antenna tuner.
>
> Thanks,
> Steve K0XP
>
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>
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