Strong spur at 4241 kHz

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  • Updated 2 months ago
  • (Edited)
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


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KD2OM

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Posted 2 months ago

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N5LB - Lionel B

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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.
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Duane, AC5AA

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S6 spur at 4244 kHz here on my 6600 with Maestro.  No big deal. 
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N5LB - Lionel B

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Internal - no issue. 
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KD2OM

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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

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Tim - W4TME, Customer Experience Manager

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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.
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Thomas PA1M

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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.
(Edited)
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Tom W3FRG

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I also see it wobbling around 4240.7 +/-. It varies between S2 and S7.

All antennas disconnected and input grounded.

Tom   W3FRG
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Tim - W4TME, Customer Experience Manager

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It's the noise from an internal voltage switcher.
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KD0RC

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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
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Tim - W4TME, Customer Experience Manager

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It's the noise from an internal voltage switcher.
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Pat - WH6HI

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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. 
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KD2OM

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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 
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Pat - WH6HI

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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.  
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Pat - WH6HI

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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.