The Heartbreak of RFI

Occasionally I find a way to remind myself that I am not very smart.

After several weeks of what I assumed were just terrible band conditions, I finally realized something else was causing my difficulties making contacts. While I’ve not fully identified the issue, I believe a local source is generating intense noise that has rendered the HF bands largely unusable for me.

At first I wondered if my EFHW antenna had been damaged when the support cord failed. The interference first presented itself after I re-hung the antenna.

Over the weekend I finally put together my POTA PERformer antenna and did some comparisons, both between it and my standard EFHW antenna, and between the IC-7300 and IC-705. While the noise was certainly different on the POTA antenna, it was still present, and I think indicative of how horizontal and vertical antennas will react differently to noise sources. I also went through the process of killing every circuit in the house, one-by-one, to see if that knocked the noise down. It did not.

How does this noise manifest itself? There is a higher-than-normal baseline noise level from 20 meters up, which is why I thought it was just propagation. Saturday I attached the choke from my POTA antenna to the feed line for the EFHW and, at least on 20 meters, the noise was quickly knocked down. Still present, but stations that were inaudible without the choke suddenly popped up.

Secondly, below 20 meters there are large “blobs,” for lack of a more technical term, of noise that repeat at regular intervals (see attached photo). There are also various warbles and birdies at regular intervals that were not present a month ago.

I also compared my reception at home to that on an online SDR located about an hour away. None of the noise was audible on the SDR.

I’m not technical expert, but seems like that means it is something local. A new invisible fence? A set of bad dimmers? A touchlamp? Any one of several significant construction projects within a few blocks of our house? Whatever it is, it is royally F-ing up the high frequency bands.

Weather allowing, I’m will go to a local (city) park this week to fire up each radio and see if that clears the air, so to speak. If it is as simple as that, I suppose I’ll shift to mobile operating for the warm weather months while monitoring (and hoping) that the local noise disappears. It has been steady for three weeks so I am worried it is permanent and will basically render my home shack useless. Which then puts the whole hobby into question for me.1

I’m not ready to write off home operations completely. But it is a huge bummer after six months of near-perfect entry into the hobby, during which being on air has become an integral part of my daily routine.

  1. I can already envision the eye rolling from my wife when I tell her I’m going all-in on some other Old Man Hobby… ↩︎