[Elecraft] Noise from Solar System

[Mike Dodd]

On 2/6/2025 11:29 AM, John Pierce via Elecraft wrote:
> I am planning to install Solar on my house.  Any experience you have had
> regarding the inverter as an amateur radio noise source would be of real
> interest.   Noise may vary by Mfg or by inverters at each panel on the roof
> vs one system inverter near my basement.  My antenna is a Hex beam an the
> solar system would be about 15' away.

I installed a solar power system in 2012: 
<http://house.mdodd.com/project_solar.html>

We have 14 PV panels that produce about 4 KW of solar power, 15 KWH of 
battery capacity (to 50% discharge), and an 8 KW inverter in the 
basement that is wired into a dedicated breaker box wired to most house 
circuits (obviously, no high-power stuff like oven, dryer, water 
heater). The inverter does power the well water pump and the geothermal 
HVAC system.

The only RFI I've experienced is hash on 160 and 40 meters when the PV 
panels are producing power (e.g., during the day). Right now it's 
overcast and the PV panels are producing 300 watts. Right now the K4's 
band scope shows the hash at -110 dB on 40M and -105 db on 160M. 80M is 
at -115 dB.

My Carolina Windom antenna is about 40 feet above the ground, and 
parallel to the buried 150-foot cable from the PV array. The cable is 
buried in an 18"-deep trench.

I remember carrying a KX3 outdoors with a short wire antenna just after 
installing the system, and the RFI was pretty high as I walked over the 
cable trench, but decreased rapidly as I moved away.

I have no experience with inverters on the PV panels, but the 8 KW 
inverter we have is _not_ the source of my RFI. That comes from the 
charge controllers between the PV panels and the batteries.

Hope this is somewhat helpful.

73, Mike N4CF