Richard, VK3LRJ, is a recent licensee and when he initially set up his HF station was disappointed with the high level of noise across HF.
It didn’t take long to figure out that the culprit is Richard’s off grid solar and battery system. Some noise came from switch mode battery chargers but the vast majority from the inverter.
Although he moved the antenna (an Off Centre Fed Dipole) from the building with the solar and battery equipment, noise remained quite high.
A call to the inverter supplier produced the suggestion that the capacitors need to be “serviced” every few years as they degrade. These high power inverters are an impressive piece of equipment.
Richard ordered a new set of capacitors and replaced them. This had an immediate good effect.
Noise varies but in general the noise floor has dropped from about S9 to around S5 which is quite significant.