Oscilation on spectrum when 6700 is first turned on

  • 1
  • Problem
  • Updated 6 years ago
  • Not a Problem
This is a problem I reported about 2 months ago but I did not receive an offical responce at that time.
When I boot up the Radio ( 6700 GPSDO WIN 7 HP I7 laptop) I get the spectrum shown below.

This usualy last for apx 4 to 30 minutes and graduallychanges to the spectrum shown in the second screen shot below.

These "Humps" can last for minutes to hours before they disapate. Except for the first few minutes, in screen shot 1, the "Humps" don't seem to hurt anything operationally. But they are not right and they bother me ( I guess distract me would be a better description).
Usually during the day my RF noise floor goes so high that the spectrum just completly turns into a straight line and I can't hear any thing anyway. By the time my noise floor is back down(8 to 10 pm) the humps are very small.
I'm not concerned with the humps because they may be related to my antenna, A 7 band vertical (Cushcraft R7). But I really do want to find out about the oscilations.
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Posted 6 years ago

  • 1
Photo of George Molnar, KF2T

George Molnar, KF2T, Elmer

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What kind of power supply are you using? Is it a switching type? Is there anything else attached? Can you swap out supplies and see what you get?
Photo of K2CM


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I think that George is correct. It looks like noise from a power supply. If it is still there when you disconnect your antenna, its probably the p/s.

You probably want to solve this as it could cause noise on your transmitted signal.
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Dave - WB5NHL

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If you come up with any culprits please post. As you can see I have very similar interference. In my case it is definitely external .i.e nothing without antenna or dummy load. I havn't been able to track it down yet.
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Mack McCormick, Elmer

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As Dave suggests, what do you see with a dummy load attached or using a different power supply or battery? I have never seen this behavior from my 6700 with GPSDO.

Please let us know what you find.


Photo of W4EG


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if you have touch controls to turn lights or other device in your home turn them off. It may not be you but your neighbors too. I had similar noise. However, I found the culprits with my F5K several years ago. Solution, disable them: you'll never see them again.
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K1UO - Larry

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Some Wall-Wart transformers can cause this same indication also.. usually just on certain Bands but sometimes several Bands at a time.If you havent done so already, I would check any of these in the shack especially but also in the house. I had one HDMI cable from the Sat TV receiver that caused a similar pattern also. the RFI reflector has tons of good ideas on troubleshooting and even pictures of different types of noises.
regards, Larry K1UO
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Tim - W4TME, Customer Experience Manager

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Official Response
As described, this looks like external noise and not a problem with the radio, per se.

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