Modern suburban noise floors are appalling. Almost all of it is local, and almost all of it is fixable — it is coming from something in your own house or a neighbor's.
Common sources
- Switch-mode power supplies and phone chargers (buzzing across whole bands)
- LED and fluorescent lighting, and dimmers
- Solar inverters and EV chargers
- Plasma TVs, ethernet-over-mains adapters, aquarium heaters
- Utility pole hardware — arcing insulators produce a rasping buzz over huge distances
Finding it
- Kill the main breaker and listen on a battery radio. If the noise stops, it is yours.
- Restore circuits one at a time.
- Outside the house, use a portable receiver on AM or a handheld with a directional antenna and
- Utility noise: log the times and directions, then report it to the utility. They have RFI teams,
walk the noise down.
and arcing hardware is a fire risk they care about.
Fixing it
- Ferrite chokes on the offending device's power and data cables.
- Replace the cheapest offenders — a $6 charger causing S7 noise is not worth defending.
- A receive-only antenna (loop, flag) sited away from the house helps on the low bands.
- Noise blankers and DSP noise reduction help with some noise types and none of the others.
Interference you cause
If a neighbor reports interference: be polite, respond immediately, and get on their side of the problem. Most cases are poor immunity in consumer equipment rather than a fault in your station, but "the FCC says it is their problem" has never once ended well. Filters, chokes, reduced power and a friendly manner solve nearly all of it.