Flex 6700 - S Meter Readin - Noise (This is more of a poll than question)

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Back in November I've had a noise problem crop up.  It looks like its a power line issue and my utility company has been working the problem trying to find the cause.  While the problem has not been resolved, I'm pleased with the utility company's willingness to solve the problem.  They have the proper equipment,  it's just a matter of finding the pole/line causing the problem.

With the noise, my S meter is reading around S5 to S7 with a nice fried egg sound.  The noise floor is any where between -110 and -120 db.  This was on 20 meters (14.200 +-)  The NB and/or WNB do a nice job taking care of the noise, but noise blanker's introduce artifacts with close in strong signals.

If I remember correctly,  my S meter on a clear frequency prior to the noise was S3 and a noise floor between -120 and-130 db.  This was on 20 meters as well.

That being said, what is a good noise floor and s meter reading on a  clear frequency?  Is S3 at -120 to -130 db satisfactory, or should I be striving for better?  When does it become an atmospheric issue that can't be resolved?  For example the lower we go in frequency like on 80 meters, the more difficult it becomes to reduce the S meter reading.  I am working on installing a receive only antenna to help in this area.

I can't move my qth, but maybe I need to research common mode chokes ect....

What kind of S meter readings are others getting on a clear frequency?

Rich - N5ZC
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Rich - N5ZC

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Posted 3 years ago

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Jim Gilliam

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My noise floor on 40 meters and above reads in the vicinity of -120 dBm which seems to be as quiet as I have ever seen it living in a metropolitan area. My noise floor on 80 and 160 is around -110 dBm. It appears your noise floor is pretty darn good even with the AC power line interference.


Jim, k6QE

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Tim - W4TME, Customer Experience Manager

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Rich - N5ZC

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Thanks for the link Tim,  I found another link within the link on the write up 'how to determine the amount of rf preamp....."

All very helpful on understanding how the 6000 series works.

Rich - N5ZC
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WA6HTP - Juan Rivera

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Rich,
I documented an EMI issue for my power company here: https://www.youtube.com/watch?v=x4MRo...
Our power company here in Northern California (PG&E) is notorious for being unresponsive. In spite of my continued attempts to get some support, I was unable to ever get anyone to respond to my complaint. As you'll see from my YouTube video, I had some severe arcing issues on the 12,000 VAC distribution lines that run right along the side of my shack. Bu then the drought ended here and my 20 meter noise level dropped from -115 dBm to around -130 dBm. I believe the rain cleaned off all the insulators and fixed my problem. I haven't see an arc since the rains began. Based on my experience I'd say that -130 dBm is a very low noise level for 20 meters and around -120 dBm is probably reasonable.
Juan - WA6HTP
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Steven G1XOW

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In my RF quiet English village location, my 20m noise level used to be -132dBm without pre-amps.

Now due to VDSL QRM which is present 24/7 I now see around -110 to -115 at best.

So, where I used to be able to work Asia on the long path as the band started to open in EU but still not loud enough to move the S-meter, I now have no chance until they are about S4-5.

73 de Steve G1XOW
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KY6LA - Howard, Elmer

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This graph albeit a bit dated (from Flex 5000) should explain everything... Basically -130dBm is great for 20M and being able to hear better than -130dBm is a waste



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KY6LA - Howard, Elmer

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The other thing is S0 = -127dBm,  S9=-73dBm

Most engineers refer to dBm rather than S units

Especially since Most S_Meters LIE and are NOT calibrated to mean anything