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Strong spur at 4241 kHz

KD2OM
KD2OM Member
I am getting a strong wobbling spur at 4241 kHz. I have disconnected everything from my 6600M except power which is a car battery, so it is internal.



Anyone else see this?

73,
Steve KD2OM


Answers

  • Lionel
    Lionel Member ✭✭✭
    edited April 2020
    I see it at 4242.5 or so. Only about S6 here. it looks like it is drifting up, slowly as it wobbles. It is present when Flex antenna is grounded. Same on DL.
  • Duane_AC5AA
    Duane_AC5AA Member ✭✭✭
    edited April 2020
    S6 spur at 4244 kHz here on my 6600 with Maestro.  No big deal. 
  • Lionel
    Lionel Member ✭✭✭
    edited April 2020
    Internal - no issue. 
  • KD2OM
    KD2OM Member
    edited April 2020
    Mine is about S7, I do consider it an issue as it is near a frequency I use for a non-ham service. But since others see it I guess there is nothing specifically wrong with my radio.
    Thanks
    73
    Steve KD2OM

  • Thomas PA1M
    Thomas PA1M Member ✭✭
    edited April 2020
    In my case this is a Samsung television in the same room as the Flexradio. Even without an antenna attached the carrier on 4244 kHz is still s8. With antenna 9+++. There is also a carrier on 925 kHz (s7) from the same television. This is not only when active but also when the televion is in standby. The only solution is to disconnect the mains (220/110 v) cable. Then the carriers are gone.

    Not internal to the Flexradio.
  • Tom W3FRG
    Tom W3FRG Member ✭✭
    edited April 2020
    I also see it wobbling around 4240.7 +/-. It varies between S2 and S7.

    All antennas disconnected and input grounded.

    Tom   W3FRG
  • KD0RC
    KD0RC Member, Super Elmer Moderator
    edited April 2020
    I unplugged all TVs, DVD, etc equipment and no change at all - the wobbly carrier is still there.  I will try the experiment again when I get this thing out in my camper away from all EMI and operating on battery power.
    73,
    Len, KD0RC
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited April 2020
    It's the noise from an internal voltage switcher.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited April 2020
    It's the noise from an internal voltage switcher.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited April 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.
  • Patrick
    Patrick Member ✭✭✭
    edited June 2020
    Many times problems like this are not engineered out, because it would add cost, such as PCB board re-layout.  Especially if it is caught in the development process.  Cost would be engineering labor, new layout design and proof and production, then the cost of the added parts.  So a decision is made, since, not in the ham bands to wait or not do anything with this.  These cost would increase unit cost.  Another words the bottom line profit per unit.  This is an important business consideration. 
  • KD2OM
    KD2OM Member
    edited April 2020
    I would normally agree with you Pat but Tim says it is a spurious from an internal switcher. Switcher noise should be able to be suppressed. 

    Steve KD2OM 
  • Patrick
    Patrick Member ✭✭✭
    edited April 2020
    No, that is what I was talking about, it would require additional design changes.  It would take extra components as the switcher is an integrated device.  I had this same problem on a Flex3000, it was fixed with added bypass capacitors of appropriate values.  Work was done by Mr. Youngblood himself.  
  • Patrick
    Patrick Member ✭✭✭
    edited April 2020
    Maybe I was not clear.  I said development.  But I was thinking about the entire development cycle, from initial design to production.  The later in the process you fix problems means increased costs per unit. 

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