Noise Antenna for Noise Canceller

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N5CM, Dec 31, 2019.

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  1. N5CM

    N5CM Ham Member QRZ Page

    I have ordered an MFJ-1026 noise canceller. Some like it, and some don't. I'm hoping it helps.

    I plan to use it primarily in the CW portions of 80m and 160m. Based on what I've been able to find, my auxiliary, or noise, antenna doesn't have to be all that large. It should be capable of hearing the most of the noise and not a lot of the target signal.

    Recently, the noise on 160m has increased dramatically compared to what it was at this time last year. Last winter, my background noise would get down to about S7 and on really good nights, S6. We've made no electrical/electronic changes in our household. I'm thinking this noise may be local, but I can't prove it.

    I thinking about building a 6 meter vertical dipole as my noise antenna that could be used to reach our 6 meter repeater when I'm not on low band CW.

    If you have a noise canceller with a passive noise antenna, what sort of antenna are you using?

    Tnx es 73, HNY de N5CM
     
  2. AK5B

    AK5B Ham Member QRZ Page

    I have a Timewave ANC-4 and while I don't need to use it much I just connect a wire to the back to pick up our neighbor's noisy tv---works well.

    A lot depends on the type of noise and where it's coming from---if it's atmospheric it won't help at all---but it will null ONE source of man-made QRN very well. I've heard of ops employing several of these at the same time so as to null multiple different sources, too, FWIW.

    Try to locate the source beforehand if you can---that will improve your chances of accomplishing effective noise-nulling.

    73,

    Jeff
     
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  3. N1UKX

    N1UKX XML Subscriber QRZ Page

    I have the MFJ-1026 on my boat and have tried various outside noise antennas but I found the little one supplied with the unit worked the best for my situation.
    The MFJ-1026 took the noise level from a S-7 down to S-3, allowing me to actually use my radio at the marina.
     
    AK5B likes this.
  4. WA7ARK

    WA7ARK Ham Member QRZ Page

    I have a MFJ-1026 here that I bought to mitigate noise from a neighbor's roof-top grid-tied solar system (13 panels and micro-inverters). Problem is that the solar array subtends a fairly large azimuth angle, as I found out when I tried to null it with a directional loop. It is really multiple separate noise sources spaced apart in azimuth, and with the loop, I could null them all, but only one at a time....

    The '1026 was not effective, and I suspect that it is exactly for the reason cited by Jeff. Even with the noise antenna placed in the side yard, closest to the solar panels (which are about 100ft away), only a slight reduction in the noise could be achieved.

    btw- I have an unused MFJ-1026, if someone wants to try it, make me an offer... I have also been able to reduce the RFI emissions from the solar array by using commercial packaged LC pi-section 240Vac line filters installed at the micro-inverters. Don't ask about the politics of making that happen...
     
    Last edited: Dec 31, 2019
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  5. KD0CAC

    KD0CAC Ham Member QRZ Page

    I would suggest the small telescoping antenna be moved around to help find local /indoor noise and have an outdoor antenna larger , maybe one each vertical & horizontal on antenna switch also can vary for what noise is most of the issue .
    Then use antenna switch to use one or the other for what ever is an issue .
    I have a Timewave also , not using currently , not sure if it can be connected to the indoor & outdoor antenna at the same time , haven't used for yrs. have to re-read the manual .
    It can only be use on one antenna / noise source at a time .

    Basically I saying multiple antennas each setup to find different noise sources / tune to , and use as needed .
     
    AK5B likes this.
  6. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    I have used the -1026 in my last townhouse. It can be quite effective for certain noises that are within it's capability. However, there are limitations to what it can do.

    There are number of good web pages that discuss how to setup and use the the device. Some quick tips:

    1. Put away the provided telescoping antenna
    2. Hook up the keyline blanker so you don't blow the box.
    3. Put up a 'noise" antenna that is of similar design, or at least the SAME POLARIZATION as the main antenna.
    4. Distance between the two antennas can help
    5. Study the manual on theory and operation. Read it again. Practice.
    6. Set radio AGC to FAST or OFF. Turn off all other audio filters, DSP, NB etc. while making adjustments to the 1026.
    7. Use you S-Meter as primary reference back up by your hearing. The S-Meter is more sensitive and more accurate than your ear.

    8. As with most MFJ products a bit of attention to quality issues and a few easy mods will significantly improve performance.
    -Check for missing parts, loose screws, etc.
    -Put star washers on all case screws, grounding points and metal standoffs that act as grounds.
    -Put a drop of Deoxit on all the star washers and ground points.
    -Larger replacement knobs will improve ease of tuning and all more precision.
    -My 1026 phase knobs were quite stiff and need a drop of oil.
    -Tip for other MFJ devices" Twist any long, paired hook up wires to minimize signal pickup, e.g. meter leads, battery wires, etc.
    ***Many MFJ devices will be more stable, less twitchy if circuit ground resistance is minimized and the case screws are well bonded with star washers.

    Comments:
    -The phase noise canceler works on only a single frequency noise at a time. It can't cancel multiple noise sources.
    - It can't cancel noise from sources at significant distance like Lightning, band noise static, etc.
    -It can't cancel noise sources that are extremely strong or very close.
    -Noise that is being radiated from multiple directions e.g. house wiring, may not cancel.

    The MJF-1026 is a great device within its' capabilities. It takes some time to grasp the theory and understand the operation methods. b.

    Tom W8JI designed the 1025/1026 as well the similar devices sold by DX Engineering. He has some comments and tips at his site:
    https://www.w8ji.com/mfj-1025_1026.htm
     
    Last edited: Dec 31, 2019
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  7. K1VW

    K1VW Premium Subscriber QRZ Page

    I have an SDRduo which will do diversity reception. I was thinking I should experiment with canceling noise using that, and if I come across a successful combination, I can use what I learned to deploy with something like MFJ-1026. I think if I tried to use the SDRduo while transmitting the secondary antenna would potentially overload and maybe fry the front end, so I shouldn’t try to run like that, I should use something made for the purpose. But I’d rather not buy a dedicated box and find it doesn’t suit my situation if I can avoid it.

    My question is : Is that a realistic, equivalent, test? I’m concerned about “false positives”, where I fail with SDR and don’t try the hardware solution, when the hardware solution would have worked much better.If a dedicated box has specialized DSP algorithms which the SDRuno software doesn’t replicate, then it’s apples and oranges, and I shouldn’t bother. Or maybe it’s a case of “it’s not rocket science, it’s just a couple of amplification and phase shift adjustments and the software and hardware versions are equivalent”. I expect other people have been down this path, I just haven’t read about it.
     
    Last edited: Jan 1, 2020
  8. AI3V

    AI3V Ham Member QRZ Page

    Aint nuthin digital about a mfj-1026:

    [​IMG]

    And there would be exactly zero difference in performance with a sdr based copy.

    And of course the sdr version would require both hardware (a/d converter, cpu,d/a converter) and the software to run it.
    Rege
     
    Last edited: Jan 1, 2020
  9. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    But does the SDRduo actually have a phase cancellation process? Simply beating inverted signals against each other is not the same thing as phase cancellation. Tom W8JI, mentions this point in comparing the 1026 to other devices.
     
  10. HB9PJT

    HB9PJT Ham Member QRZ Page

    Seems to work very well.

    73, Peter - HB9PJT

     
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