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Author Topic: Local Noise Levels - How is Yours?  (Read 2451 times)
VK5EEE
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Posts: 1044




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« on: October 28, 2017, 09:59:03 PM »

It would seem that, in spite of the many other onslaughts and threats against amateur radio and CW operators, from spectrum threat, over the horizon radar, radio manufacturer$, national $ocieties, dx tourori$m, terrori$m, etc etc the biggest threat overall is the rising noise levels.

30 years ago, it was we hams who created noise for the tell-lie-vision sets, and were even blamed for washing machine malfunctions, microwaves breaking, etc, but now it is us who suffer increasingly intolerable levels of noise from grow lamps, lights, tell-lie-visions, everything.

I'm even hearing from Siberia about impossibly high noise levels from local street lighting, that and power lines, traffic lights, etc a near universal problem too. What about you? How is your noise levels? How do they vary? Please include meaningful data, e.g. with pre-amp on, filter width...

I'll start: location a city of one million population, suburbs, medium density population, noise from screens, lamps, power lines, varying intensity, pre-amp on, S meter, wide CW filter 80m S9, 40m S8, 30m S7, 20m s5, 10m S1, or with narrow filter 200Hz about 2 S points down. That is worst case, it varies, seemingly randomly over time, and is an accumulation of many different noise sources, some with peaks every x kHz, some broadband.

Best case with narrow filter on is 20m S3, 30m S4, 40m S5, 80m S6. Antenna used: 2x6m horizontal balanced doublet, 80m short vertical.

Looking forward to trying QCX "QRP CW Xcvr" from portable locations to see if can find any places with low noise levels.
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Long Live Real Human CW and wishing you many happy CW QSO - 77 - CW Forever

Support CW and join CW clubs. QTT: FIST#1124, HSC#1437, UFT#728, RCWC#982, SKCC#15007, CWOPS#1714, 30CW#1,
W7ASA
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Posts: 455




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« Reply #1 on: October 29, 2017, 07:52:03 AM »

Totally agree.  I live in what was once a very rural/RF quiet area.  However, immense and rapid growth have brought with it RFI: power line arc sizzle, grow lights (undocumented pharmacology...) , plasma TV (for High Definition brainwashing) and more - my S-9+ noise level on most bands was reduced by using a horizontal loop, and GREATLY REDUCED by using my old Noise Cancellation Bridge that I've used down through the years.  It is a life saver for taking out the worst offender of the moment snd nulling it out, berfopre it even reaches the front end of the radio.  


Link to demo of one:  https://youtu.be/Xumllo78o7o

Winter is on it's way, so portable at a picnic table is soon to be gone, so the little mini-camper van might soon have a radio desk so that I can drive out away from the din of increasing urbanization to non-electric areas near me.

The two worst sources of radio interference for me are: urban electronics and contests - not necessarily in that order.


73 de Ray  ..._  ._
« Last Edit: October 29, 2017, 08:05:37 AM by W7ASA » Logged
GW3OQK
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Posts: 386




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« Reply #2 on: October 29, 2017, 08:25:41 AM »

RSGB have been doing such a survey with 800+ responses and I await results. They are particularly interested in VDSL. https://www.surveymonkey.co.uk/r/RSGB_VDSL_survey Fortunately my levels are S3 or less, except S9 carriers from the neighbour's solar installation at 19 kHz intervals above 12 MHz, but it's gone at night.

I have just posted something in the Contesting forum about the bad mannered SSB B's wiping out the bands.
73
Andrew
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NK7Z
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« Reply #3 on: October 29, 2017, 09:28:56 AM »

I have been using a technique of keeping track of my RFI for the past two years or so...  Using an SDR to document the RFI.  See:

http://nk7z.net/sdr-rfi-survey-p1/

For a how to on how to document your RFI in a relatable, meaningful, accurate way.  I have my last doc spectrograms up for 80-10 meters there as well.  Shows ALL RFI on the entierity of each band, across a24 hour period.
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Thanks,
Dave
For reviews and setups see: http://www.nk7z.net
K8AC
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Posts: 1763




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« Reply #4 on: October 29, 2017, 10:07:01 AM »

Other than summertime thunderstorm QRN on the low bands, I have no noticeable noise here on the HF bands.  Sometimes you just get lucky.
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M0LEP
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Posts: 489




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« Reply #5 on: October 29, 2017, 12:13:46 PM »

RSGB have been doing such a survey with 800+ responses and I await results.

I gather the results (or at least a first pass at analysis) were presented at the RSGB Convention, and the VDSL picture was less than encouraging.

I know that VDSL is more than a bit of a problem at my QTH, especially with its propensity to generate nasty spikes at 4kHz intervals up the bands. Knocks certain spot frequencies out of court...
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VK5EEE
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Posts: 1044




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« Reply #6 on: October 29, 2017, 10:22:06 PM »

I have been using a technique of keeping track of my RFI for the past two years or so...  Using an SDR to document the RFI.  See:

http://nk7z.net/sdr-rfi-survey-p1/

For a how to on how to document your RFI in a relatable, meaningful, accurate way.  I have my last doc spectrograms up for 80-10 meters there as well.  Shows ALL RFI on the entierity of each band, across a24 hour period.
Amazing work NK7Z!! What is the result overall, is there over these two years a clear trend of getting worse, or is it too variable? Do you live in a built up area?
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Long Live Real Human CW and wishing you many happy CW QSO - 77 - CW Forever

Support CW and join CW clubs. QTT: FIST#1124, HSC#1437, UFT#728, RCWC#982, SKCC#15007, CWOPS#1714, 30CW#1,
NI0C
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Posts: 2935




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« Reply #7 on: October 30, 2017, 10:14:54 AM »

A panadapter is extremely useful for measuring noise.  My QTH is an "inner suburb" of St. Louis Missouri.  Here are some results from my transmit vertical, measuring with an Elecraft P3: 

80 Meters: -100 dBm in 50 KHz bandwidth; -110 dBm in 2 KHz bandwidth
40 Meters: -105 dBm in 50 KHz bandwidth; -115 dBm in 2 Khz bandwidth

On 40 meters, however, I have some noise spikes as strong as -75 dBm.  I have no idea of the source of the noise spikes, but I can null them down to the baseline noise level with the aid of a broadband loop noise antenna and a DXE NCC-2 noise cancelling device. 

For reference: -73 dBm corresponds to "s9" -109 dBm corresponds to "s3."
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M0LEP
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Posts: 489




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« Reply #8 on: October 30, 2017, 03:49:54 PM »

RSGB have been doing such a survey with 800+ responses and I await results.

See here: http://rsgb.org/main/blog/news/rsgb-notices/2017/10/30/results-of-the-vdsl-interference-survey/
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G4LNA
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Posts: 144




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« Reply #9 on: October 31, 2017, 06:50:41 AM »


Call me Mr Cynical, but those results only something like 0.0002% of the population that are suffering problems from VDSL, Openreach and OFCOM will almost certainly carry on burying their collective heads in the sand and do nothing.

I've now got myself another hobby to occupy me if this interference gets much worse and it's nothing to do with radio.
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KB2SMS
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Posts: 59




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« Reply #10 on: October 31, 2017, 07:29:06 AM »

I live a few blocks from an AM station which kills me on parts of all HF except 10m. I bought an MFJ 1026 and what a difference! And I only use the incuded telescopic whip.
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"My best advice to anyone who wants to raise a happy, mentally healthy child is: Keep him or her as far away from a church as you can." - Frank Zappa
NI0C
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Posts: 2935




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« Reply #11 on: October 31, 2017, 07:40:12 AM »

I live a few blocks from an AM station which kills me on parts of all HF except 10m. I bought an MFJ 1026 and what a difference! And I only use the incuded telescopic whip.

A high-pass filter in your receiver might also help you-- wouldn't have any adjustments to make.  Say, how did you obtain the nice green display on your KX2?  Mine is orange.  I'll have to check the manual to see if the display color is a menu option.
73,
Chuck  NI0C
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KB2SMS
Member

Posts: 59




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« Reply #12 on: October 31, 2017, 07:55:09 AM »

I live a few blocks from an AM station which kills me on parts of all HF except 10m. I bought an MFJ 1026 and what a difference! And I only use the incuded telescopic whip.

A high-pass filter in your receiver might also help you-- wouldn't have any adjustments to make.  Say, how did you obtain the nice green display on your KX2?  Mine is orange.  I'll have to check the manual to see if the display color is a menu option.
73,
Chuck  NI0C

The "green" is with the backlight off. That's all.

73!
Tom
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"My best advice to anyone who wants to raise a happy, mentally healthy child is: Keep him or her as far away from a church as you can." - Frank Zappa
AE5GT
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Posts: 29




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« Reply #13 on: October 31, 2017, 08:51:18 PM »

I live a few blocks from an AM station which kills me on parts of all HF except 10m. I bought an MFJ 1026 and what a difference! And I only use the incuded telescopic whip.



I would use a 3-5 element notch filter if possible. Stubs would probably work better but might be a bit long . 
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VK6IS
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Posts: 303




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« Reply #14 on: November 02, 2017, 05:16:54 AM »

generally, my noise levels are quite low,
but, every so often, the noise level will hit S9 on the lower HF bands,
and I've turned just about everything Off - - even the Rooftop Solar Power System ..
yet I've never really figured out where that noise is coming from . . .

it's not always there & when it is - - I'll typically just Switch Off & walk away Sad

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