Wide band, vertically interleaved interference


My antenna is a 1.2 meter copper loop with a LZ1AQ commercial amplifier. I have a 15dB Mini-Circuits attenuator in line to prevent OL.
I have this strange wide-band noise (see attachment). I don't understand why the noise skips certain parts of the spectrum forming those curious noise-free vertical bands.

Feel free to check the receiver out and play with the NB, if you wish. I'd really appreciate!




  • I forgot to mention that I use the Chinese Linear Power supply suggested in the KiwiSDR documentation. The board is not enclosed
  • I think those clean bars are caused by balun sense (phase) mismatch, but I'm guessing. I'm going to watch this thread and learn something. Hi Hi
  • Hi Alain,

    I think it could be interference from a data over powerline adaptor. Take a look at the spectrum used by this device.


    They are used to carry ethernet around the home over the mains power cabling. The interference often stops and starts when the ethernet link is being used. Unfortunately they radiate quite badly and can cause interference over a large area. Some manufacturers include notches on specific frequency bands and I think this is what you are seeing.



    Martin - G8JNJ
  • That could be the explanation... :/
    Thank you
  • Definitely mains networking as Martin says, the notches should line up with HAM bands at least.
    In the UK Sky Q boxes are well known for it (you can turn the mains networking off but that does not disable the hardware so the issue stays.)
  • I wonder if a filter could be built for this specific type of problem...
  • No - there's no filter for that kind of wideband garbage! The only way is not to use this nonsense ... to feed HF on unshielded cables with undefined impedance and thus unmatched means that a lot of HF is radiated.
    However, it's also often used here in Germany. The industry lobby did a good job in Brussels to get CE for a technique that never can meet any limits.
  • edited December 2018
    Eckrot 5G next, 700Mhz, 2.3GHz, 3.5GHz, 26GHz, 60GHz, 100G+ once they get going. I know it shouldn't affect HF but sure as hell it will affect health, industry lobbying to the max.
    I'm sure one of the reasons they are pushing so hard on it now is that it is difficult for the average user to do a .5-120GHz sweep to see what they are being subjected to, and for what, faster Facebook videos? so your fridge can order milk on it's own? Mains networking is bathing users (and their neighbours) in dirty supply RF, 5G phone will be 24/7/365 radiation in all locations.
    I know this sounds like a rant but I'm happy to follow link to independent health studies that have been performed before the roll out..
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