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No hash for three days - just beeping!

For some reason I have not see any hash-type interference here for about three days. I'm certainly glad for that, but what has taken over is beeping as shown in the following video. Both 20 and 40 meters were captured:

Because the regularity across the band is the same as the hash, they must be related. I'll do some more direction finding in the car today to scope out the nature of this RFI.

BTW, the frequency of the beeping in the video has not changed in over 12 hours since I've been monitoring it!

Intervals (harmonics?) from beeps to hash

Usually, as seen on the following spectrogram, the same interference pattern (or hash) is seen at recurring intervals


This suggests to me harmonics, but harmonics of what? I recently asked in the eHam RFI /EMI forum if something else I have seen could be recognized by anyone else. Here is the post.

The jump from one frequency to another is almost regular, but not quite. Starting at 7.037 MHz in the above video the spacing or separation is 55, 57, 55, 57 kHz. In the "beeping" video from the eHam post, the separation is 58.8, 59.1, 58.8, 59.1 kHz. This certainly shows that the beeping and the hash are somehow related but I have no idea how. Do you?

I don't see the hash RFI continuously. It seems to be mostly present daily during the week, but not 24 hours straight. I cannot figure out a pattern. On weekends in seems to be less prevalent. Perhaps some industrial source? Once I caught on video the interference starting up, and progressing to a well formed hash pattern:


This …

The interference is spread over a wide area

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About a year and a half ago I first became frustrated enough with this RFI problem to ask for help in the RFI/EMI section of the eHam forums, see here. Although the image referenced in that post has been lost, it is similar to the image shown in the previous post to this blog.

In attempting to identify the source, I eventually operated my radio, a Kenwood TS-480, from a 12 volt gel cell battery and shut down all the power to the house. The noise persisted unabated. I did this more than once, certain I had missed something. Anything with a battery I disconnected. I disconnected the phone and cable lines where they entered the house. Same problem. I put ferrite on almost everything. No help. Well, the easy way out was not to be had.

In July 2017 I bought the RSP1 software defined receiver from SDRPlay. This inexpensive receiver aside from being a really good receiver also made it easier to see what was going on in the ham bands and elsewhere and provided one of the tools I used to resea…

About HF RFI in the ham bands

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I've had terrible HF RFI (High Frequency Band Radio Frequency Interference) for over a year at my QTH (location). I've asked many people for advice and will undoubtedly be asking many more. In order to facilitate this, I am developing a one-stop web location where I can describe what is going on, and show pictures, videos, and other media to help explain the problem.

Many people I will be inviting to this site are not ham radio operators which is why I frequently will have simple explanations of ham radio jargon, for example. Perhaps this blog will be useful to other hams (amateur radio operators).

Before going any further, let's quickly look at what the problem is. This short video shows a spectrum, spectrogram (also called a waterfall display), and audio of a single instance of an interfering noise source within a small section of the 40 meter ham band:



For many of you the audio will sound familiar, and perhaps the appearance of the spectrogram. Some people have said tha…