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strong interference in the range of 40-20-15 meters

Max Member
Hello colleagues. what could be? on the video at the waterfall ... especially from 58 seconds https://youtu.be/rXge-XwFpu8
This is a HY GAIN 640 vertical antenna.
On a dipole of 40 m (height 3 m above the ground) this does not happen.
I tried the work of my flex from the battery and turn off all the devices that are in my house (Internet routers and other emitters). It did not help.
I am glad to any answers.


  • John - AI4FR
    John - AI4FR Member ✭✭
    edited November 2019
    Looks just like the noise I get with one of the monitors here. Playing with the AC cord and transformer fixed it here.
  • VE3DZP
    VE3DZP Member ✭✭
    edited November 2019
    Max the only way to determine if your house is the problem is to run off the battery and pull the mains. I have a similar looking noise on my 6400m to and have tracked it down to something on the street be hind me. Think is a underground xformer. Walked around the area with a multi-band hand held and was worse at 10 meg, tough to find good luck.
  • Max
    Max Member
    edited November 2019
    I turned off  power of  whole house (I have a private house) and turned on my Flex 6400M from  battery (12 volts 30 am.h.). I HAVE AN ICOM R20 SCANNING RECEIVER. Can I use it to search for interference? what is the search technique?
  • Ha Gei
    Ha Gei Member ✭✭✭
    edited November 2019
    Some power supply or the like creating common mode , vertically polarized radiation, This is my guess. Use  portable receiver of some sort and walk around until you find it. Sometimes bad switch mode supplies can send dozens of meters. Also expect outdoor stuff like automatic lawn mower charge stations etc. etc.   

    I nowadays use an rtl-sdr connected to my adroid phone

  • Wayne Schonfeld
    Wayne Schonfeld Member ✭✭
    edited March 2020
    I had this problem with switching power supplies for household applications like security cameras.
  • John KB4DU
    John KB4DU Member ✭✭✭✭
    edited November 2019

    What ever you use be best in AM mode. I have a Yaesu 7900 in the auto. When set to the aircraft band (108-135.9) it defaults to AM. I then drove around the area until I had detected the power pole that generated the noise. For smaller sources, this may get you close, but not down to the device.  A portable radio might do if you can get permission to track it down on someones property. When searching for aircraft ELT's, removing the antenna reduced the radio sensitivity enough to narrow the search area.

    Happy hunting.
  • Bill W2PKY
    Bill W2PKY Member ✭✭
    edited November 2019
    Had a similar problem, found it with a portable SW radio. Turned out to be a switching power supply in my neighbors swimming pool controller. The fact that the dipole antenna does not hear your interference probably means the source is closer to the vertical than the dipole. Once you find the source then a plan can be employed to eliminate the RFI. 

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