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Author Topic: S9 Static noise mainly on 160 and 80m with some on 40m  (Read 453 times)

NO9E

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S9 Static noise mainly on 160 and 80m with some on 40m
« on: March 07, 2022, 06:44:03 AM »

Recently I am hearing static noise - discharges about every 1-2 second. The discharges are strong on 160 and 80m, about S9, weaker on 40m (S5) and nothing heard on 20-10.

The noise starts around 10 PM and ends about 6 -8 AM. I have beverages in 7 directions and the noise is present in all directions although it is a few db stronger to NE.   

The station is in the country. I walked half a mile at night with a directional loop to NE. The noise did not change and I could not identify a distinct direction.

Any idea about a noise that is heard on 160-40 and not beyond, and does not show a distinct direction?

Ignacy NO9E
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WA3SKN

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #1 on: March 07, 2022, 07:17:04 AM »

You have a local noise source. Try to locate and filter it.
What do you turn on in the house about 10 pm?
What types of directional antennas do you have available for the frequency range?
Get the radio on a battery and try turning off circuit breakers.

-Mike.
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W9IQ

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #2 on: March 07, 2022, 07:28:06 AM »

Any idea about a noise that is heard on 160-40 and not beyond, and does not show a distinct direction?

Ignacy,

Noise that is carried by the power lines often exhibits "non directional" characteristics (think very long antenna). You may get some advantage by checking directions with your loop at frequencies below 160 meters. Also consider a variable/step attenuator (up to 60 dB) to help with the DF.

It is also helpful to do some sanity checks with your DF setup by DF a couple of known signal locations.

- Glenn W9IQ
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

K6SDW

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #3 on: March 07, 2022, 08:00:09 AM »

Take a portable AM receiver, shut off power to your house (making sure XYL not home) and wander the area for noise....MFJ has a directional finding unit they sell, kinda pricey, but it works.

GL/73
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W2JJV

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #4 on: March 07, 2022, 12:02:38 PM »

Had a similar situation and discovered a neighbor with an electrified fence on a timer.  Conveniently I had a nosy neighbor who knew everything about everyone in the neighborhood and took me right to the house.  He was correct, had my little radio, asked them to shut it down and the noise went away. 

Good luck,
David
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NO9E

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #5 on: March 07, 2022, 12:25:16 PM »

The fence seems a good idea. Often the noise is only on the weekend. Many properties are used by weekend hunters.  I am just wondering why the noise is mainly limited to 160 and 80m, and nothing on 20m.  Does it give any indication how far the noise is?

The noise started about a week ago and there was no change at my house. Also, with noise coming from my house, the directional antennas would point to the house. I had some small noises before, and traced them by disconnecting the mains. The noises were from a wart for a router, UPS and a NUC.

For RFI hunting I use KX3 with a tuned loop or a directional loop with preamp by DXE, MFJ 3 el, MFJ dish. F6A on 70cm. Also EME 2 x 9 array with 2m radio in AM mode.   

The current noise is different from that from electronics as it is just discharges every second or two. With discharges on power pole, I find that 15m and 10m can travel really long, and 20m just barely.

Ignacy NO9E
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K5TED

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #6 on: March 07, 2022, 02:00:03 PM »

The half mile thing seems to me to point to power or cable tv lines. Typical home electronics offenders like warts and chargers won't have that kind of range. Agree that the fence thing seems plausible.


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KH6AQ

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #7 on: March 07, 2022, 04:55:07 PM »

The reduction in signal amplitude with increasing frequency is, I believe, dominated by the event finite current rise time (~100 ns).

Due to the 1 second rate I suspect it is an electric fence that is being charged (pulsed) or possibly charged and then arced.
« Last Edit: March 07, 2022, 05:08:08 PM by KH6AQ »
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W9IQ

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #8 on: March 07, 2022, 05:00:07 PM »

The reduction is signal amplitude with increasing frequency is due to the event finite current rise time.

I suspect it is an electric fence that is being pulsed and then arcs over. These 1 second rate points to an electric fence.

The reduction in amplitude with increasing frequency could also be attributed to FSPL or ground wave attenuation.

I agree with the possibility of an electric fence but the weekend bias does not track with my ranching experience unless the neighbor just happens to be rotating livestock into the same paddock zone on weekends.

- Glenn W9IQ
« Last Edit: March 07, 2022, 05:06:43 PM by W9IQ »
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

W2JJV

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #9 on: March 07, 2022, 05:07:22 PM »

Could be using the fence as nighttime protection against animal intruders.  My problem was day-only because the owner had a dog that could jump the fence.  Also had gates with jumpers and splices and therein lay the problem.  Poor splices.  They act like it's fence wire not an electrical conductor!

David
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W9IQ

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #10 on: March 07, 2022, 05:42:30 PM »

If it is an electric fence, things to look out for are trees, branches, weeds, etc. that touch the electric fence, conductive objects that are too close to the fence such as bent gate hooks that cause arcing or poor/corroded splices in the fence wire. The voltage is upwards of 10 kV on a well built fence with a premium charger and it is capable of a couple of joules of energy per event.

If the ground system for the electric fence is bad or marginal, this can enhance RFI if the fence is actively discharging.

"Modern" ranchers have a handheld meter that can be touched to the fence wire to show the discharge current in that section of fence. They will know if something has changed once they take the measurement. The simplest test is to briefly power down the charger to see if the interference is gone. The handheld meter on better fencing systems supports the ability to remotely turn the charger on and off.

- Glenn W9IQ
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

KL7CW

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #11 on: March 08, 2022, 12:53:40 PM »

Decades ago, I had RFI from various electric fences.  The RFI was most severe on the BC band and 160 meters and much less so at higher frequencies.  In all cases except one, this was from fences less than or much less than 1/4 mile away. The one exception was that there was a fence roughly 2 miles distant.  I identified one or two of the bad ones, and the owners were happy to let me walk around fix their fence.  It was most typically just a weed or branch touching the hot wire.  At that time the units put out a pulse about once a second.  It must have been a short duration steep pulse, since it was easily eliminated by my Ten Tec Omni noise blanker set at only a moderately low level which caused no detectable distortion.  I have not bothered chasing down noise, since several rigs have easily handled it, and now there are no close neighbors who have horses.  One clue is that the noise amplitude will be dependent upon the weather and the state of the weed growth, unless it is due to poor wire splices etc. 
     I have no idea how the pulses are generated in modern times, so some of this info may not apply.  If modern fence chargers operate like the old ones, I would speculate that if an ordinary noise blanker does a good job of suppression, the fence is a strong possibility.  Many other types of noise RFI are not handled well even in modern rigs with various noise reduction schemes.    Rick  KL7CW
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N0GV

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Re: S9 Static noise mainly on 160 and 80m with some on 40m
« Reply #12 on: April 17, 2022, 05:02:57 PM »

Fence - look for a garden or trees with fruit (not this time of year, but...) and someone trying to keep wildlife out of their garden plot. Pulse rate is a pretty good giveaway.... Can also be a flourscent tube that is flicker starting....

Grover
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