Help/suggestions with noise

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  • Updated 3 years ago
Hello Flexers!

I realize this is not the radio noise bureau but I am starting to track down some rather interesting noise in my shack.

I have the wonderful quiet station powerpoint mentioned in other threads and I've started down that path with some good success.  Just using some of the ideas in the powerpoint I've gone from about S8 on 40m to about S4.  I realize that is not a quantifiable measurement but just a relative point that seems to show progress.

I opened up my flex6300 to look at large segments of bands to see what might be going on and I noticed something on 20m that bothers me.  Please see the movie with audio at:

https://dl.dropboxusercontent.com/u/7578983/20mNoise10192015.mp4

This noise is a very low level noise that seems move occupy several places: 14.015, 14.075, and 14.125 and up but in about the same intervals.  If you look closely at the movie you can see that the oscillations back and forth in each of the three areas shown roughly follows the other areas.

Just curious if anyone has run up against something like this?

I'm about to get hold if I can of one of those noise meters and starting searching around.  First I thought I would try to isolate if something in the home is causing this by slowly turning things off.

Anyway as someone said in another thread now the hunt begins to try and figure out noise and make the station as quiet as possible.

Thanks in advance for any ideas!

Mark WS7M
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Mark - WS7M

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Posted 3 years ago

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Simon Lewis

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Mark

best way to track this down ...

power the flex from 12V battery and use a laptop for SSDR\

turn off the power and unplug EVERYTHING in the house ..

measure the base noise and sprogs from there and then turn on power and do same

then stuff slowly room by room

my burglar alarm was terrible until I fixed the PSU for example 

broadband router .. fixed!

but you need to do it room by room .. bit by bit

helps if you have a helper or 2!

I found the worst was a PSU for a LCD picture frame!

my place is mostly noise free at the temp QTH I am living in

the rest is external TV's PSU's etc

good luck :)

Cheers
Simon   
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Mark - WS7M

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Hi Simon,

Ok well that will be the plan.  When you say measure the base noise and sprogs I assume you mean starting with Flex on bat and laptop take a baseline average on all bands there.

Then turn on one thing at a time until noise appears.

Next question is if the noisy thing is say a wall wart for some device like a network switch what is the best fix?  I don't really want to build clean power supplies for everything in the house.  I've invested a small fortune in the cores you can clip on to lines but I'm curious how you fixed your router and burg alarm PSU?

Thanks again!

M
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Simon Lewis

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I fixed mine with a variety of ways

wrapping PSU round cores you can find on PC's/TV's etc ... also some nice ferrites I brought at a rally

but I did have to throw away some cheap ones and invest in some others

the Alarm was simple wrapped round a core ...

the broadband was same ... took a couple more to quieten it down on 6m but managed!!!

The picture frame was terrible ... threw that one!

We are building a new house and the builders offered LED downlights ... I declined... i need some time to investigate decent noise free ones!

thats also something to hunt down .. bedside clocks!   I had a bedside clock that caused ticks all up the HF bands at some freqs ... that went too :)

You really have to spend time and effort and also think about what your switching on ... does it contain noise!

Baseline noise .. IE everything outside of you is nigh on impossible to control ... ie next doors PC! ...

from there you slowly power up the house .. check the bands .. power a bit more .. check ... until you find the offending item but don't be surprised when its something very unexpected!

:)
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KY6LA - Howard, Elmer

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We could only use LED Down lights throughout our house as we had no choice but to use LED under the California Building Codes when we remodeled it in 2013.

Took a bit of experimentation on a number of different brands (in 2013) , but i found really quiet ones sold by Costco.. Some of the more expensive brands sold by Home Depot were much noisier. 

Being that you are in ZL you might need to buy a few from your local electrical supply house to test them for noise..

BTW.. my LED are much quieter than the fluorescent lights they replaced

The added bonus is that they use much less power and seem to last forever.

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Roy - W5TKZ

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Hi mark,
I had a similar noise in my shack that took some time to run down because it was the PS in my radio computer. Seems the panels of the PS were not screwed together. They were only held in position by dimples in the sheet metal. I found the culprit by removing the computer side panel and pushing on the PS case while watching the radio screen. I cured my problem with a sheet metal screw that broke the paint between the PS panels.
I also found that some wall-warts present a similar pattern.
   
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Norm - W7CK

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To clean up noise at my QTH, I've been running EVERYTHING off of 12v battery bank.  This is also great for emergency communications.  When the electric goes out, I still have internet, computer and speakers all work as well. I then wired up a bunch of pigtails for devices that use wall warts. They now all run of of the battery bank.  I've gotten rid of a lot of noise this way.  Another approach is to use a very good quality 12v power supply like you use for your Flex and power your wall warts through that.  I was lucky because every wall wart I had was 12v DC.   Just a thought!  

I do have a few items that require 120v AC.  I'm looking for a quiet full sine wave inverter to power those items during a power outage and or while camping in the 5th wheel.
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Mark - WS7M

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Well after a little work I've already made a major improvement.

I have moved my 6300 to be battery based with a side charger for the battery that is really quiet.

I've braid enclosed many cables including power cables and single point grounded things including the computer.  I've taken many of the wall-wart type power supplies and choked them.  I plan to see which ones can I move to a linear supply.

Anyway with just this work here is the way 20 looks now:
https://dl.dropboxusercontent.com/u/7578983/20mPhase1NoiseReduction.png

I still have a ways to go but its getting there!  Thanks to everyone for suggestions and help.
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Mark - WS7M

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I've done further snooping and traced the vast majority of this noise to the UPS for my development computer!   I have not started to try and remove the noise yet but it is frustrating this thing, a fairly expensive UPS is causing this noise.

Here are the things I'm thinking of trying:

1) Ground the outer case - The easiest fix
2) Try to scope out the noise using my O-scope (take the cover off an poke around inside)

Before I try #2 I thought I was ask here about any of you that are using UPS on your computers. 

a) What brands are you using?
b) If you had a noisy one what did you end up having to do to clean it up?

Thanks in advance!
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Roy - W5TKZ

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Mark,

I use an APC UPS. I had to ground the case to get rid of some noise. Be sure to insulate the ground braid for some distance from the ground point on the case so it doesn't come in contact with any of the plugs on the UPS. 

Roy - W5TKZ
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Mark - WS7M

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Hi Roy, Thanks.

This is an APC 1100.  I've grounded the case so far but it still can be seen noise wise.  This is going to take a little snooping I guess!

Mark