Interference help

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  • Question
  • Updated 2 years ago
Has anyone seen this kind of interference. I tried mans things without succes. Thanks for any information!
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Peter PA3PM

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Posted 2 years ago

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Photo of G8ZPX


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almost certainly noise form a switchmode PSU.
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Mark - WS7M

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I agree.  

If you have a laptop and you can somehow battery power your Flex then direct cable them.  IE lan goes from PC directly to Flex.  Some people have managed to use a WiFi access point on battery so they can carry the laptop around.

Now unplug EVERYTHING in the house until you find the thing (or things) that start to cause interference.

If you go battery and unplug everything and it is still there then it is from a nearby source not within your house.

I did this exercise myself and only got part way through it because there were TONS of things plugged in and I just ran out of time.
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Here's my checklist - you would be surprised how much you can discover when you logically lay out the info. I'd be curious if others have additional things to check. This could evolve into a useful flow chart.

1.       Does the noise occur 24/7 or only at certain times of the day? (Street lights and advertising signs come on at night, while noise from solar panels will occur during daytime hours).

2.       Are there any street lights in your neighborhood that aren’t working and appear to constantly cycle or “flicker”?

3.       Does it occur on multiple bands or only one specific frequency?

4.       Is it a repetitive noise, a signal that seems to appear at evenly spaced intervals, say every 100 khz?

5.       Is it visible when the antenna is disconnected?

6.       Is the noise present when all household circuits, except that which supplies power to the radio area, is turned off?

7.       Is it possible to temporarily shut off power to the radio area and obtain power from another circuit? When doing so, is the signal still present?

8.       Does the noise seem to decrease or completely go away when it rains? This usually indicated bad HV insulators on a nearby power pole.

9.       Is it visible on multiple antennas? How about on a simple indoor antenna?

10.   Is it visible when the Flex Radio is connected to another PC, one not normally used?

11.   Is it visible when the Internet service is temporarily disabled (including all wireless devices, switches and hubs?)

12.   Can the noise be received on another conventional analog receiver?

13.   Using a yagi, even a tri-band yagi, can the source of the signal be seen to increase in one general direction?

14.   Has a neighbor recently had a new Internet service installed?

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Jim Gilliam

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An effective way to battery power the Flex and your Internet service is to use a UPS. I have found most of them are clean. Then, remove all the power in your house. Quickly it becomes overtly obvious if the source is coming from your QTH. I use a UPS on the Flex system , router, and  Ethernet switch, anyway.

Jim, K6QE
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Stan - VA7NF

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My portable solution has a NetGear (ProSafe series) that is on the 13V bus; with a small lithium battery (UPS SLA format) the station is self contained and can run for over an hour.  A PS is part of the package but not needed when hunting noise.
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Tim - W4TME, Customer Experience Manager

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And turn off WNB.  This is not well correlated periodic noise and enabling WNB can make the situation worse.