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Strong signal at or near 4.24MHz

George Moranian
edited August 2020 in Amateur Radio Interests
With no antenna connected and dummy loads attached to both Ant. ports I am getting a very strong signal at or near 4.240 MHZ
The only items attached to my 6600 with v3.1.8.145 is the ethernet connection and power from a battery. (to eliminate possible switcher freq.)
Has any one else seen this? Is this a internal oscillator/LO generating this, or possibly computer generated through the Ethernet connection?

George N1NAZ


  • KD0RC
    KD0RC Member, Super Elmer Moderator
    edited May 2020
    Hi George,
    Here is a link to discussion about this spur.  In a nutshell - it is internal.

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    edited May 2020
    It's the noise from an internal voltage switcher.  Since the radio is only guaranteed to be internal noise-free in the ham bands, I am afraid there isn't much that can be done about it.

    Mike va3mw

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