Another RFI thread

[kilokat7]

Well, I woke up to this crud on the radio this morning :-(

The strongest being centered around 7.4 mhz. I ruled out anything local to my house by killing the main breaker, the RFI was still there. Note the "DNA" pattern in the first image - anyone recognize it? It sounds like constant static, similar to noise generated from a dimmer switch. Luckily the noise blanker on the Perseus SDR kills it completely so I can deal with it.

Are there any resources that identify RFI sources based on an audio recording or spectrogram/waterfall image? This sure would be useful and would make a nice Wiki article. Maybe we can get something started.

 

[NK7Z]

Rfi

Hi,

I also have an RFI issue... Most of it is chronicled at:
RFI

There are a few links to software which may assist you in characterizing the noise there...

Dave
NK7Z
NK7Z Amateur Radio reviews and software setups

 

[kilokat7]

Hi,

I also have an RFI issue... Most of it is chronicled at:
RFI

There are a few links to software which may assist you in characterizing the noise there...

Dave
NK7Z
NK7Z Amateur Radio reviews and software setups

Thanks - I'll check this out.

Here's a video with audio of the interference:

RFI Hell - YouTube

In looking at other YT vids of RFI, my interference sounds similar to those experiencing powerpole interference.

 

[k9rzz]

Time to move to da U.P.

 

[BDM123]

Hi,

I also have an RFI issue... Most of it is chronicled at:
RFI

There are a few links to software which may assist you in characterizing the noise there...

Dave
NK7Z
NK7Z Amateur Radio reviews and software setups

Did the power company "shave" that pole? Any further update from them? I have RFI issues with the same noise though not as severe, and not related to my current RFI carriers from hell noise. It also occurs only when very hot outside. Of course we all know that could change for any reason. I know it's power line/insulator related having dealt with this issue back in the mid 90s.

I agree with Kilo. That sounds like power line RFI.

 

[kilokat7]

I've been monitoring the RFI the last few nights and have discovered a pattern. It suddenly disappears every night at 7:30pm and returns at some point in the morning. Even though it sounds like powerpole RFI, I'm guessing there must be another cause because of the pattern. At least it's occurring during the daylight others and not the other way around.

 

[jim202]

I've been monitoring the RFI the last few nights and have discovered a pattern. It suddenly disappears every night at 7:30pm and returns at some point in the morning. Even though it sounds like powerpole RFI, I'm guessing there must be another cause because of the pattern. At least it's occurring during the daylight others and not the other way around.

You say 7:30 PM, every night. By any chance does this change slowly a few minutes each night in the same direction? Reason I ask is some AM radio broadcast stations have to leave the air or reduce power at sunset. Have had some strange problems with them over the years. The tuning of their antenna systems from dry ground to wet ground also makes a difference.

 

[Sol100]

A few things to think about. Pool chlorinator's, solar panel inverters, washing machines, CRT and plasma TV's, touch lamps and dimmers, electronic speed controllers, certain types of lighting and man made radio transmissions. All of the above could cause interference through harmonics and don't even have to be in the house. Your problem seems to be set between two times, even knowing the cause it can be difficult to locate the origin.
What about doing some RF sniffing with a portable SW receiver, it can work sometimes.
Good luck

 

[ab2ms]

Now I'm kicking myself again to tackle my rf problem. Most bothersome on 60 meters, but present in many spots along the dial. Time to analyze the on off pattern, look at the signal, where it occurs, weather effects..... All the good stuff.

 

[kilokat7]

You say 7:30 PM, every night. By any chance does this change slowly a few minutes each night in the same direction? Reason I ask is some AM radio broadcast stations have to leave the air or reduce power at sunset. Have had some strange problems with them over the years. The tuning of their antenna systems from dry ground to wet ground also makes a difference.

Thanks for the suggestion. I only have one nearby BCB station and the station's pattern change time doesn't correspond with the on/off times of the interference I'm experiencing.

 

[kilokat7]

I've since discovered the interference starts at 7:34am, every day, seven days a week. It goes off twelve hours later at 7:31pm. It must be something running on a timer. I've discussed it with the two nearest neighbors who verified they haven't added anything on a timer. As someone suggested, I suppose the next step is to sniff around outside with a small portable SW receiver.

Here's a new video recorded just seconds after it fired up the other morning. Listen to this horrid noise and look how awful this thing drifts when it first starts up:

Part 2: HAM Shortwave Radio broadband RFI Interference buzz static. Grow Light? Powerline? Help? - YouTube

Anyone have any experience with interference generated by grow lights? I'm starting to wonder...

 

[ridgescan]

walk the portable kat-that's how I found my budfarmer here-although the RFI characteristic was totally different than yours. The one here was coming through the wiring in MY building-doorbells, fire alarm runs etc! That little pocket radio did very well for me. I had him nailed within 10 minutes. Best of luck.

this was mine
http://www.youtube.com/watch?v=lqZO9HoJgTg

 

[brandon]

Oh my!!!
Part 2: HAM Shortwave Radio broadband RFI Interference buzz static. Grow Light? Powerline? Help? - YouTube
This is noise is eerily similar to what I have been experiencing since last December. It would start around 7:50pm and go until 7:50am (same times daily 12 hours on a timer). It has disappeared maybe 2-3 times since December, but always returns a few days later. It still plagues me to this day, but I am able to null it by using one of my loops. I took a handheld radio and walked around my neighborhood and it's heard over a wide area at least 1 mile.

HDSDR view when this thing fires up

Recording when RFI starts: http://solarix.org/audio/terrible-rfi-noise-start.mp3
Recording when RFI stops: http://solarix.org/audio/terrible-rfi-noise-end.mp3

Additional images from HDSDR

 

[brandon]

I should also add the noise is most noticeable from around 7 to 9 megs range.
Lower and upper bands don't seem to be affected by it.
Noise floor rises to -90 normally its -110 to -120 range for me when things are quiet.

 

[kilokat7]

I should also add the noise is most noticeable from around 7 to 9 megs range.
Lower and upper bands don't seem to be affected by it.
Noise floor rises to -90 normally its -110 to -120 range for me when things are quiet.

Wow Brandon. I just listened to the audio that you posted. It's identical to the sinister sound I hear when it first starts up. And yes, mine is also strongest between 6 and 8 MHz and on a 12 hour timer. So what the hell is this? Now I'm really curious.