We are at the mercy of a multitude of noise sources in and around our ham shacks these days. I built myself a very useful tool for sniffing out noise sources a few years ago.
I had bought a working battery powered Heathkit preamp for a few dollars at a hamfest and hadn’t really found a use for it. It struck me that providing it with a tunable ferrite bar antenna input would be useful. With it I could “sight” along the bar and Direction Find (DF) using the deep null off of the ends of the bar antenna.
After a bit of juggling with parts in my junk box I found the right combination of parts and coil turns to give me a 40m thru 10m tuning range. Mounting it on the side of the preamp made a neat package that then sits nicely on top of my old FT 817 QRP radio. All pieces run on their own batteries, allowing me to walk around to sniff out noise sources.
A quick way to check your own home is to power up your HF radio from a battery and then turn off your whole house AC power. If the noise goes away then you’ll need to switch back in each area/room to find the offending noise source.
Some of the regular offenders are PC Laptop cord chargers, and wall wart PSU plug in units. LED replacement bulbs can also cause noise. Most newer bulbs seem very quiet, but some of the tube replacements are not so good.
Fish tank pumps/lights, trickle chargers for garage tools, RV trickle charger systems, and Ethernet switching/distribution boxes, and even your WiFi distribution hubs can be noise sources.
Good luck with your noise hunting. Don’t forget to call and ask for help from club members too!
