Author Topic: Interference and Noise  (Read 100302 times)

0 Members and 1 Guest are viewing this topic.

Offline Knickohr

  • Member
  • *
  • Posts: 49
    • Der Sternhimmel ueber Ulm
Re: Interference and Noise
« Reply #125 on: June 27, 2014, 07:53:43 AM »
 \:D/

Thomas

Offline dfroula

  • Forecaster
  • *****
  • Posts: 551
Re: Interference and Noise
« Reply #126 on: June 27, 2014, 08:41:09 AM »
It looks like low-frequency sinusoidal interference with the lightning signals riding on top of it.

Did you get those antennas out from under the metal roof? That could cause some odd issues.

Don
WD9DMP

Hi All,

Got some crazy looking frequency graphs tonight.  Don't know how to interrupt this.

This weekend I will take my system down and check out the amplifier board and see if there is a soldering issue.  Also will try to shield the ferrite antenna. Up until now it has been unshielded.  Also will relocate the controller board to a slightly different location, just a couple of feet away from my weather computer that is running 24/7.  Up until now it is just about a foot away from this computer. When I move it it will be about 4 feet away from this computer and hope it will make some difference.

Currently the amplifier and antenna is about 25 feet away from the amplifier board.  Cannot get it any further away than this for now.

Any suggestions or ideas that I could improve my interference issue will be very much welcome.

Regards,

--Stan Y.
   Maui, Hawaii

Offline Silversword

  • --Stan Y.
  • Forecaster
  • *****
  • Posts: 558
    • Up Country Maui Weather
Re: Interference and Noise
« Reply #127 on: June 27, 2014, 01:04:59 PM »
Hi Don,

It is still under the aluminum roof in the attic.  Just to see what happens.  When I take it down this weekend for some work on the amplifier and shielding the ferrite antenna and perhaps making an enclosure for an outside box for the amplifier and antenna and see what happens in a couple of days of down time to get it up and running.

Will keep on trying..

Thanks for your input..

Maybe Mike will be able to see what is going on too.

Regards,

--Stan Y.
  KH6HHG
  Maui, Hawaii
Stan Y. - KH6HHG - Maui, Hawaii
 --- Blitzortung ID: 993
 --- FlightRadar24 ID: F-PHOG1

WDL 6.05
MS Windows 7 Pro
Dell Optiplex GX280-Intel Pentium 4 CPU 3.00GHz, 4 GB RAM
Davis Vantage Pro 2+ Wireless
Webcam: Axis 211

Offline meteo-melin

  • Member
  • *
  • Posts: 22
    • Weather station Mélin
Re: Interference and Noise
« Reply #128 on: July 03, 2014, 01:55:37 PM »
Hello,

Can someone help me debugging station 898 (region 1) signals?

It does not go in interference but has a lot of signals compared to the number of strikes.

Thanks
Clément
Weather station Davis VP2 : http://www.meteomelin.be
Blitzortung stations: 252, 680, 733. Region 1

Offline dfroula

  • Forecaster
  • *****
  • Posts: 551
Re: Interference and Noise
« Reply #129 on: July 03, 2014, 05:52:32 PM »
There is a very strong noise signal at about 20KHz on both of your channels. I suspect you have the gains set very low to avoid the noise sending your station into interference mode, as the signal rate and strike rates are quite low.

The attached signal does show a good strike detection, so your amps are likely working fine. Because of the low gains, only very strong lightning signals will be detected and sent to the server.

You need to identify and correct that 20KHz noise source!

Best regards,

Don
WD9DMP

Hello,

Can someone help me debugging station 898 (region 1) signals?

It does not go in interference but has a lot of signals compared to the number of strikes.

Thanks

Offline meteo-melin

  • Member
  • *
  • Posts: 22
    • Weather station Mélin
Re: Interference and Noise
« Reply #130 on: July 04, 2014, 04:11:13 AM »
Hello,

Thank you for the tip.
Indeed, the gains are very low.
What kind of disturber can produce a 20 kHz noise? Can it come from the station itself?

Thank you.

Regards,
Clement
Clément
Weather station Davis VP2 : http://www.meteomelin.be
Blitzortung stations: 252, 680, 733. Region 1

Offline JonathanW

  • Engineer
  • Forecaster
  • *****
  • Posts: 323
Re: Interference and Noise
« Reply #131 on: July 04, 2014, 09:48:51 AM »
What kind of a power supply are you using?  Does the noise ever go away, and did it have a defined start/stop time?

Offline meteo-melin

  • Member
  • *
  • Posts: 22
    • Weather station Mélin
Re: Interference and Noise
« Reply #132 on: July 04, 2014, 11:25:46 AM »
The noise is always present.

I use the power supply which was included in the full kit ordered to Egon: http://www.reichelt.de/USB-PA-230V-5V1A/3/index.html?&ACTION=3&LA=446&ARTICLE=97412&artnr=USB+PA+230V+5V1A&SEARCH=USB+PA+230V+5V1A

Thanks.
Clément
Weather station Davis VP2 : http://www.meteomelin.be
Blitzortung stations: 252, 680, 733. Region 1

Offline dfroula

  • Forecaster
  • *****
  • Posts: 551
Re: Interference and Noise
« Reply #133 on: July 04, 2014, 11:55:53 AM »
Compact fluorescent bulbs, laptop or other PC too close to antennas, electric dog fence, robot lawn mower are all possible culprits.

Try powering off your laptops/PCs one at a time and see if the interference stops.

Turn off one AC circuit at a time from your circuit breaker/fuse box. Note which circuit powers the offending device. If you are fortunate, the offending device will be within your home. If it is on a neighbor's property, the solution will be more difficult.

Do you have a single-point ground on the Controller board? This is especially important if you are using ferrite antennas with shields.

The amplifier may be too close to the controller. Try moving the amp/antennas so that the units are separated by at least 5 meters.

Set your LCD backlight options to run at 100% brightness with a 30-second timeout to 0%. See if the noise diminishes at 100% brightness or when the backlight is off.

You must use shielded cat 5 cabling to connect the amplifier to the controller to avoid noise pickup.

If you re-orient your antennas, does the noise shift from one channel to the other? If it does, the noise source is likely external to your system power supply/cabling.

Don
WD9DMP
« Last Edit: July 04, 2014, 12:00:09 PM by dfroula »

Offline W3DRM

  • Forecaster
  • *****
  • Posts: 3360
    • Emmett Weather
Re: Interference and Noise
« Reply #134 on: July 04, 2014, 12:24:48 PM »
Compact fluorescent bulbs, laptop or other PC too close to antennas, electric dog fence, robot lawn mower are all possible culprits.

Try powering off your laptops/PCs one at a time and see if the interference stops.
[...snip...]

I found that one of my very old Dell laptops, even though it was turned-off, was radiating high levels of noise. It went away when I unplugged the ac-adapter from the AC outlet. So, just turning a device off may not eliminate the noise source.
Don - W3DRM - Emmett, Idaho --- Blitzortung ID: 808 --- FlightRadar24 ID: F-KBOI7
Davis Wireless VP2, WD 10.37s150,
StartWatch, VirtualVP, VPLive, Win10 Pro
--- Logitech HD Pro C920 webcam (off-line)
--- RIPE Atlas Probe - 32849

Offline Dr Obbins

  • Forecaster
  • *****
  • Posts: 1152
Re: Interference and Noise
« Reply #135 on: July 04, 2014, 12:44:58 PM »
I found it easier to wait until every one else had left the house and turn everything off - even circuit breakers. This way I could tell if the noise was from inside my control or outside the house. Then went room by room turning items on and seeing if there was a change in the noise floor.

Offline Cutty Sark Sailor

  • WxElement panel
  • Forecaster
  • *****
  • Posts: 3393
    • Frankfort Weather - TwinHollies WeatherCenter
Re: Interference and Noise
« Reply #136 on: July 04, 2014, 12:54:50 PM »
I found it easier to wait until every one else had left the house and turn everything off - even circuit breakers. This way I could tell if the noise was from inside my control or outside the house. Then went room by room turning items on and seeing if there was a change in the noise floor.
Aren't you the one that removed all the light dimmers and replaced 'em with switches while the wife was grocery shopping... :twisted:

Seriously... I just gave my son a brand new ACER high end computer that he took to Colorado.... it no longer swamps my system with its stupid high level emissions. But look out Grand Junction... he's on the front range, and if you start having issues, PM me and I'll tell Him to go dump it in the Poudre River....
 


Offline JonathanW

  • Engineer
  • Forecaster
  • *****
  • Posts: 323
Re: Interference and Noise
« Reply #137 on: July 04, 2014, 01:25:22 PM »
I found it easier to wait until every one else had left the house and turn everything off - even circuit breakers. This way I could tell if the noise was from inside my control or outside the house. Then went room by room turning items on and seeing if there was a change in the noise floor.
Aren't you the one that removed all the light dimmers and replaced 'em with switches while the wife was grocery shopping... :twisted:

That's my plan, as well.  Please keep it quiet :)

Offline meteo-melin

  • Member
  • *
  • Posts: 22
    • Weather station Mélin
Re: Interference and Noise
« Reply #138 on: July 04, 2014, 02:00:53 PM »
Ok... I'll try that...

Btw, is a metallic desk a good ground?
Clément
Weather station Davis VP2 : http://www.meteomelin.be
Blitzortung stations: 252, 680, 733. Region 1

Offline Dr Obbins

  • Forecaster
  • *****
  • Posts: 1152
Re: Interference and Noise
« Reply #139 on: July 04, 2014, 02:03:27 PM »
I found it easier to wait until every one else had left the house and turn everything off - even circuit breakers. This way I could tell if the noise was from inside my control or outside the house. Then went room by room turning items on and seeing if there was a change in the noise floor.
Aren't you the one that removed all the light dimmers and replaced 'em with switches while the wife was grocery shopping... :twisted:
uh.....yea..... :-"

Offline dfroula

  • Forecaster
  • *****
  • Posts: 551
Re: Interference and Noise
« Reply #140 on: July 05, 2014, 11:26:30 AM »
That is NOT a good ground, and will possibly make your interference worse by acting as an antenna for the noise.

"Ground" in this context means a wire run to a metal rod that is driven into the ground at least 1 meter or so in conductive soil.

An alternative might be to connect to the home power wiring protective ground at a power outlet wall plate. I'm not familiar with how residences are wired in Belgium, but there should be protective ground at the power outlet that does not normally carry current. Niko-style plugs have such a ground (http://www.niko.eu/nlbe/niko/artikel/100-66601). That protective ground must be wired to a suitable ground rod at your power distribution panel.

Don
WD9DMP

Ok... I'll try that...

Btw, is a metallic desk a good ground?

Offline Knickohr

  • Member
  • *
  • Posts: 49
    • Der Sternhimmel ueber Ulm
Re: Interference and Noise
« Reply #141 on: July 06, 2014, 06:01:55 AM »
Today, it's very quite, not much lightning, only a few strokes around Germany.

So I try to find out some other unwanted "noise-generators" and found one :

The controller itself  :twisted: The LCD, specially the voltage generation for the display-contrast :



The little sharp green spikes are produced from the negative voltage generation for the LCD. In this case, the developer should redesign this simple circuit.

Workaround :

Disable the PWM for the backlight by setting "Brightness" to 0 or 100%, setting "Auto Off" to a few seconds. This will disable the voltage generation for the contrast after the given time and also disables communication to the LCD.



Result :

After the given time, no noise anymore from the display :



This in not new, but it's a small thing to do, to avoid additional noise.

Thomas

Offline JonathanW

  • Engineer
  • Forecaster
  • *****
  • Posts: 323
Re: Interference and Noise
« Reply #142 on: July 06, 2014, 08:31:35 AM »
Thomas,
You are correct; the LCD is a known noise source.  I set the level to 100% and disabled after 3 seconds on mine.  See:

http://www.wxforum.net/index.php?topic=20439.msg201216#msg201216

Offline miraculon

  • Sunrise Side Weather
  • Forecaster
  • *****
  • Posts: 4107
  • KE8DAF
    • Sunrise Side Weather in Rogers City MI USA
Re: Interference and Noise
« Reply #143 on: July 06, 2014, 01:23:00 PM »
In addition to defeating the PWM on the controller, I found a small advantage to disabling "flash prefetch". I posted this earlier.

http://www.wxforum.net/index.php?topic=20439.msg208992#msg208992

Quote
I tried un-checking the "Flash Prefetch" Option under the "System Settings".

This seems to have lowered my noise floor from the 20-30+mV range to 10 -<20mV. My "relative gain" has increased after running a while this way. So far, I haven't noticed a deterioration in response to the web interface or other performance issues.

The comment balloon says this about this function:
Quote

    [The flash prefetch speeds up execution time, but creates some noise in the ADCs. Disable if you need higher ADC accuracy.]

Greg H.


Blitzortung Stations #706 and #1682
CoCoRaHS: MI-PI-1
CWOP: CW4114 and KE8DAF-13
WU: KMIROGER7
Amateur Radio Callsign: KE8DAF

Offline fpalafox

  • Member
  • *
  • Posts: 25
    • Hermosillo Weather
Re: Interference and Noise
« Reply #144 on: July 09, 2014, 02:41:36 PM »
Hi Guys,
I have a interference mode for the last 5 days, but looks like is a self generated signal inside the E-Field amp. I am including file. Could you give me a hand? I review all components according to electric diagram, I re-soldering all components yesterday from Amp but still signal present.

Signal is inside if I disconect pre-amp cable, or if I set to 1x1 gain, Including if I move the amp to an other place.
Wunderground: ISONORAH5
CWOP: CW2548
AWEKAS: 7184
Blitzortung: 1023 Hermosillo,Mex
www.climason.com

Offline Cutty Sark Sailor

  • WxElement panel
  • Forecaster
  • *****
  • Posts: 3393
    • Frankfort Weather - TwinHollies WeatherCenter
Re: Interference and Noise
« Reply #145 on: July 09, 2014, 04:10:30 PM »
Franciso, what is your power supply doing?  look at your signals page, and switch on the "enable 5 volt sampling".... should be nice and smooth, maybe 50mv noise grass...

This does look like an external signal getting in, however.... are you using shielded cat cable?

Mike
 


Offline Cutty Sark Sailor

  • WxElement panel
  • Forecaster
  • *****
  • Posts: 3393
    • Frankfort Weather - TwinHollies WeatherCenter
Re: Interference and Noise
« Reply #146 on: July 09, 2014, 04:19:00 PM »
Hi Guys,
I have a interference mode for the last 5 days, but looks like is a self generated signal inside the E-Field amp. I am including file. Could you give me a hand? I review all components according to electric diagram, I re-soldering all components yesterday from Amp but still signal present.

Signal is inside if I disconect pre-amp cable, or if I set to 1x1 gain, Including if I move the amp to an other place.
Franciso, what is your power supply doing?  look at your signals page, and switch on the "enable 5 volt sampling".... should be nice and smooth, maybe 50mv noise grass...

This does look like an external signal getting in, however.... are you using shielded cat cable?

Mike
Franscisco's signals are at http://frankfortweather.us/BoStaSig/


There is a higher freq signal up around 300Khz coming from somewhere, and it must be really strong. If he's getting killed with a subharmonic, somethings coming in wild about 6Hhz
« Last Edit: July 14, 2014, 01:10:18 PM by Cutty Sark Sailor »
 


Offline fpalafox

  • Member
  • *
  • Posts: 25
    • Hermosillo Weather
Re: Interference and Noise
« Reply #147 on: July 09, 2014, 07:28:06 PM »
Thank you for your reply. I am using a 5V Samsung power supply (2A), I switch to an other and not changes, then connect the USB to standart PC USB conection and still same . 5v screen included.

From AMP to Main Board I am using a shielded 1 foot cable.
Wunderground: ISONORAH5
CWOP: CW2548
AWEKAS: 7184
Blitzortung: 1023 Hermosillo,Mex
www.climason.com

Offline Cutty Sark Sailor

  • WxElement panel
  • Forecaster
  • *****
  • Posts: 3393
    • Frankfort Weather - TwinHollies WeatherCenter
Re: Interference and Noise
« Reply #148 on: July 13, 2014, 07:57:28 AM »
7/13/2014: Added the following to the primary post:
" Among other difference between E and H fields amps: You CANNOT DISABLE E-field signals by checking "don't send" on the settings page. The server wants to see all three channels. Best you can do is set gains to 1x1, thresholds to "0". You can adjust gains. E field signals look different, and interference location is a different process.

Added 7/11/2014 ... Server signal display for active stations: http://frankfortweather.us/BoStaSig/  Shows you what the server is seeing from your station. Additionally signal spectrum is displayed to help find 'interference' frequency peaks."
 


Offline W3DRM

  • Forecaster
  • *****
  • Posts: 3360
    • Emmett Weather
Re: Interference and Noise
« Reply #149 on: July 14, 2014, 11:22:56 PM »
Looks like my 2B amp has gone south. I get a constant waveform on the channel regardless of the settings. I have dropped all inputs (Amp 1 and Amp 2) to 1.1 but the the waveform on channel 2B stays the same. Resetting everything has no effect either.

Sadly, I'm too busy with family here for the next week or so and won't have any time to work on it. I suspect something has happened with the E-field amp. It does sit in an outside enclosure and we have had temps over 100°F for the past couple of days. I need to place a temp sensor inside the enclosure to see just how hot (or cold) it does get in there.

You can see the crazy waveform on Cutty's signal info page (select the Minden station):
« Last Edit: July 14, 2014, 11:26:41 PM by W3DRM »
Don - W3DRM - Emmett, Idaho --- Blitzortung ID: 808 --- FlightRadar24 ID: F-KBOI7
Davis Wireless VP2, WD 10.37s150,
StartWatch, VirtualVP, VPLive, Win10 Pro
--- Logitech HD Pro C920 webcam (off-line)
--- RIPE Atlas Probe - 32849