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RFI -- The search continues

If you have a radio that RF Gain put it in a car with an antenna and do a slow cruise around your neighborhood. You might find a house near you is causing a lot of noise. DO NOT contact them directly! It could be grow lights for a Wacky Tabacky indoor farm.
 
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But if you partake in some of that tabacky you will soon find the noise acceptable even pleasant and inviting.
 
So, I've identified some of the major RFI generators in the house. Some addressed; some not sure how I'm going to address (like the electro-static air cleaner for the HVAC).

Down the street, I do hear power line noise that the power company is investigating.

But I did move my vertical antenna from the top of the house back down to a fence post 5' above the ground, but about 30' horizontally from the house.

My noise on 20meters dropped from S7 down to S1. Similar on other bands, especially on 80meters where I was at S9 with noise and now down to S1.

I'm really amazed that just moving over horizontally 30' reduced the RFI from the house to the Antenna by that much. I still get the occasional birdie on certain frequencies, but for the most part it is an order of magnitude in difference with the noise.

The only other difference is that the feedline is laying on the ground and not vertical along the side of the house. I don't think we were getting RFI on the coax before because if I put a dummy-load on the end of the feedline, I didn't have any noise. But that is the only two differences with the antenna location.

Scratching my head on this...

-J
 
Moving the antenna away from the house was a smart move. A lot of your noise could be conducted down your power lines in to the house. Did you find any additional noise makes in your house? Dimmer switches, Ceiling fan speed controls, electronic fluorescent light ballast?
 
Tallman,

I found lots. I've been slowly trying to eliminate them...or at least identify them so I can shut them off when I operate the radio. But moving the antenna made a huge order of magnitude of difference.

-J
 
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Jay,
I just ran across this topic on RFI and wanted to help you.
There are two distinct types of RFI:
Conducted, which runs on the cable.
Radiated, which is noise on a conductor/box that is radiated out (acting like an antenna).
Ways to fix RFI:
Bonding which is more than simple grounding. Think wide tinned copper braid straps. Copper sheet 1 to 3 inches wide. Doesn't need to be thick sheet.
Ferrites: which are big ferrite rings that you wrap your conductors around / through multiple time. Clamp on ferrites work as well but if the noise is strong enough it might take several end to end to attenuate the noise signal on a conductor.
The clip-on ferrites can saturate and allow noise to pass. So, you might need several on a line (weather DC / AC) to stop the noise from radiating.
Box / encloser can leak noise if not properly closed (missing screws on cover). These are a few things I have encountered when testing units for compliance as a Compliance Engineer at the test labs I have worked at over the years.

Ed W1RFI is the lab manager at W1AW for the ARRL. You can contact him with further questions you may have about RFI issues. Also the ARRL sections all have an RFI 'expert' you can contact.
W1RFI
USA flag
USA
EDWARD F HARE, JR
304 GEORGE WASHINGTON TPKE
BURLINGTON, CT 06013
USA

Feel free to contact me with any questions you might have.
KB5UKT@ARRL.NET Mike

Of note: the hardest thing to do is troubleshoot RFI without being onsite because it is so complicated to track/trace just exactly what is happening. I have found that you make one change and check the noise, otherwise; multiple changes between checks will leave you guessing which modification / change made the effect lessen.
 
archjeb said:
So, I know I've got other threads somewhat related to RFI - or at least antenna issues and trying to deal with related RFI issues.

But, I took some time this afternoon to shut down the breakers and run the radio on battery power to see what I have for on-premise noise and what is off-premise noise.

First off, there is indeed power company noise. Here is the clip (attached) of what I'm hearing while running on battery power and the main's shut off.

As a side note, my service entrance is almost 300' from the power pole/transformer and underground from the pole to the house. The Electric companies transformer is up the pole. So the 300' doesn't include the climb through the conduit along the side of the pole. Let me know your thought's on the attached mp3.

Now for inside the house. oh my, I can't believe how much hash and noise I'm getting. A Raspberry PI wall wort is creating the most noise and is radiating all the way outside the house! Not sure what is wrong with it...but I'll have to look at replacing.
Do the Ferrite Chokes (mix 31) help with this on the DC power side of the wall worts? Or is it really a rip and replace kind of solution?

The reason I ask, some of the wall worts are harder to replace for some more proprietary connectors on other equipment. Although they're not as bad as this particular switching power supply, they are making noise too.

At any rate, I can see that this is going to be a long,long journey to remove all the noise makers. I can't believe how much noise is created by all these electronics in the house. I'm already pulling my hair out trying to track all this stuff down.

Now I understand way some Hams like to take to low power (QRP) camping in the woods so they are well away from all this noise...

-J
Click to expand...
What freq are you using when recording? Are you using AM mode? If not, use AM and record a sample that has a few seconds of constant buzz.
 
Mike Sundstrom said:
Jay,
I just ran across this topic on RFI and wanted to help you.
There are two distinct types of RFI:
Conducted, which runs on the cable.
Radiated, which is noise on a conductor/box that is radiated out (acting like an antenna).
Ways to fix RFI:
Bonding which is more than simple grounding. Think wide tinned copper braid straps. Copper sheet 1 to 3 inches wide. Doesn't need to be thick sheet.
Ferrites: which are big ferrite rings that you wrap your conductors around / through multiple time. Clamp on ferrites work as well but if the noise is strong enough it might take several end to end to attenuate the noise signal on a conductor.
The clip-on ferrites can saturate and allow noise to pass. So, you might need several on a line (weather DC / AC) to stop the noise from radiating.
Box / encloser can leak noise if not properly closed (missing screws on cover). These are a few things I have encountered when testing units for compliance as a Compliance Engineer at the test labs I have worked at over the years.

Ed W1RFI is the lab manager at W1AW for the ARRL. You can contact him with further questions you may have about RFI issues. Also the ARRL sections all have an RFI 'expert' you can contact.
W1RFI
USA flag
USA
EDWARD F HARE, JR
304 GEORGE WASHINGTON TPKE
BURLINGTON, CT 06013
USA

Feel free to contact me with any questions you might have.
KB5UKT@ARRL.NET Mike

Of note: the hardest thing to do is troubleshoot RFI without being onsite because it is so complicated to track/trace just exactly what is happening. I have found that you make one change and check the noise, otherwise; multiple changes between checks will leave you guessing which modification / change made the effect lessen.
Click to expand...
Ed Hare has retired. The ARRL contact is Steve Anderson.
 
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archjeb said:
So, I know I've got other threads somewhat related to RFI - or at least antenna issues and trying to deal with related RFI issues.

But, I took some time this afternoon to shut down the breakers and run the radio on battery power to see what I have for on-premise noise and what is off-premise noise.

First off, there is indeed power company noise. Here is the clip (attached) of what I'm hearing while running on battery power and the main's shut off.

As a side note, my service entrance is almost 300' from the power pole/transformer and underground from the pole to the house. The Electric companies transformer is up the pole. So the 300' doesn't include the climb through the conduit along the side of the pole. Let me know your thought's on the attached mp3.

Now for inside the house. oh my, I can't believe how much hash and noise I'm getting. A Raspberry PI wall wort is creating the most noise and is radiating all the way outside the house! Not sure what is wrong with it...but I'll have to look at replacing.
Do the Ferrite Chokes (mix 31) help with this on the DC power side of the wall worts? Or is it really a rip and replace kind of solution?

The reason I ask, some of the wall worts are harder to replace for some more proprietary connectors on other equipment. Although they're not as bad as this particular switching power supply, they are making noise too.

At any rate, I can see that this is going to be a long,long journey to remove all the noise makers. I can't believe how much noise is created by all these electronics in the house. I'm already pulling my hair out trying to track all this stuff down.

Now I understand way some Hams like to take to low power (QRP) camping in the woods so they are well away from all this noise...

-J
Click to expand...
I analyzed your noise recording and found the frequency at peaks to be 58.8235 Hz. This is almost certainly power line noise. However, the audio spectrum analysis, does not reflect the typical power line response. There is one major peak, starting at 604 Hz. Not harmonics of 60, that I would expect to see.

I can tell you how to track down power line noise, but you will need tools to do this, in addition to patience.

I would need a better recording, with more constant noise for a few seconds if it is possible at higher audio level.

SL
 
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