Ham radio and RFI from system

[N1UB]

Hello,
First post on the forum, I installed an off grid system at my weekend cabin earlier this summer. The system consist of two Trina 255 watt panels, a Classic 150,MN panel , Magnum MS 4024 and 8 Trojan T-104s. Everything works great for my needs, except a lot of RF noise (S9) on all the HF bands on my ham radio. I'm pretty sure the inverter is the culprit. I shut off the inverter and lose 3 S units of noise, even running the radio on a battery I get lots of noise if the inverter is on. I made a call to Magnum and didn't get much help, they mentioned a line conditioner but not much detail.

Just wondering if anyone had some ideas? I really like the system other wise and I'm kind of bummed because one of the reasons I shelled out extra for a pure sinewave inverter was just for less noise on the radio. And the inverter and panel is grounded with #6 copper to an 8' rod into moist soil
Thanks

[Doug]

Hi N1UB,

You can try ferrites on the in and output of the inverter.
I imagine the inverter and the antenna/ transceiver are mounted an not easily repositioned but that can help.

Doug
KG7UNU

[Vic]

Hi Barton (?),  welcome to the Forum,

Just looked at the specs for the MS 4024,  and cannot find a reference to that inverter being FCC Emissions compliant  --  would hope that it would beet FCC Class B ...

But,  in any case,  as Doug mentioned,  placing a stack of several Toroidal Ferrite cores (donuts) with the AC output leads from the 4024 wound through the cores could help.  Would suggest winding the two inverter output AC hot leads,  and the Neutral lead through the cores,  all together,  in the same direction.

You may be able to use #8 AWG cable,  or perhaps #6.   The size of these wires would be (essentially) dictated by the rating of the circuit breaker that protects the inverter output cables.

Would suggest using 2.4 inch diameter Type 31 material for the cores,  and stacking 3 - 4 cores together,  using electrical tape to hold them .

There are ferrite materials that are somewhat better than type 31,  but do I not follow these trends,  and Type 31 material is a good place to start.

The inverter AC output leads are probably the most significant sources of emissions,  and this is probably the most bang for the buck/effort to begin with.   But,  other leads can also conduct emissions from inside the inverter,  and there might be some benefit in using Snap-On ferrites on them,  if needed.

MPPT CCs can also be significant sources of conducted emissions on the HF frequencies,  below 30 MHz.

Also touched on by Doug,  if there is a way of isolating the antenna/s from the power cables,  and PV array,  there is usually a large benefit.   And if you are using directional antennas,  trying to locate these antennas away from the power electronics  and cables,  and with any primary direction of interest in a direction away from these power production items.  That is,  try to place the antenna such that when it is pointed in the primary direction of interest,  the power system,  and cables connected to this equipment are behind the directional antenna ...  this is often not possible,  as ALL directions are of interest.

FWIW,  73,   GL.   Vic

[Halfcrazy]

I had the same issue here and ended up swapping out the Magnum. There was a write up by a fellow ham that showed a lot of work on quieting the Magnum. I will see if I can find it

[N1UB]

Thanks for the replies, nice to hear from some fellow hams. I will try the ferrite cores, I think I have some from a balun project. I'm sure part of the problem is the 80m dipole I use runs about 15 feet over the top of the shed that houses my solar equipment, hard to relocate on the wooded lot, maybe have to try a vertical antenna if the ferrite doesn't do the trick.

Ryan, that would be greatly appreciated if you found some Magnum specific info, because unfortunately swapping out the Magnum isn't in the budget.

Thanks, Bart
73