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Solar panel RFI

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K3RW, Jul 27, 2016.

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  1. K3RW

    K3RW Ham Member QRZ Page

    I'm thinking of putting up a bunch of solar panels on the new house.

    Some people have complained about the noise and interference coming from the panels. I'm not sure if 'turning them off' when I want to use the rig would make any difference. Or if the RFI is more of an issue that can be fixed (like shielding it properly, etc.).

    Any wisdom on this one?
  2. AC0GV

    AC0GV Ham Member QRZ Page

    Solar panels do not make noise of any kind. If you use the power as DC you will have no problem.
    Inverters and RV converters how ever are an RF noise problem. (AC operated LED house lights are a good jammer as well.)
    NH7RO, KK4NSF, K3RW and 1 other person like this.
  3. KD0CAC

    KD0CAC Ham Member QRZ Page

    2nd that , no noise from panels , possibly from the panels that have mini-inverters on back , but do not remember any talk about those and noise .
    The other related gear can make noise - chargers / charge controllers , inverters - many of the larger / quality inverters have all above in one cabinet .
    I was into solar for over 35 yrs. but a new-be in ham radio 10 yrs. and have not done hole house system since being into ham radio .
    Can not remember , others talking about brands of inverters that make little to no noise .
    But there are at least 2 steps to the RFI issue , finding the correct gear to prevent creating and building your station to deal with the noise .
    Good source for alternative energy / solar ,
    RFI & solar
    K3RW likes this.
  4. K7GQ

    K7GQ Subscriber QRZ Page

    April 2016 QST page 33 had an excellent article on this very subject. It caused my supplier-to-be to rework their initial proposal.
    K3RW likes this.
  5. AA7EJ

    AA7EJ Ham Member QRZ Page

    In my recent experience with existing solar setup primarily used to power few 12V fluorescent (!) lights, water purifier and commercial FM radio plus sat phone I noticed strange birdie when going from TX ( SSB 100W) to RX.
    This whistle kinda off audio lasted few seconds and repeated few times with diminishing intensity.
    The controller ( DC to DC) would also (slowly) indicate lower discharge (batteries) current same time.
    The display was digital.

    After about 10 seconds the RX was back to normal, no birdies.

    Apparently the controller did not handle the abrupt change in overall load on the setup.

    The unknown solar panels would supply over 35 V / 15 A at full sunlight and the controller charged 12V batteries of dubious capacity / age. Running 100W SSB TX should not be an issue for the physical size of the batteries.

    Shirley /6

    PS I did not record the controller brand name , but it was rated to run 50A .
  6. K5VV

    K5VV Ham Member QRZ Page

    I've heard of RFI from some inexpensive controllers, but no problems here.
  7. KK4NSF

    KK4NSF Ham Member QRZ Page

    I've got to vote with the "no noise from solar panel" sentiment. I've got 4 kw of panels on top of my fishing camp / cabin, and they are as quiet as a church mouse. (that's actually a metaphor. I have no idea how quiet a church mouse may or may not be.... since I've never seen a mouse at church. Of course that may be because they are very stealthy, and don't draw much attention to themselves. ;) )

    One bit of solar gear that can be noisy are the Inverters that change the DC into 110vAC. Synchronous inverters, which match the AC from the system to the incoming AC from the power lines, are typically the noisiest types. Some charge controllers can also cause some problems as noted above. Battery systems, independent of the AC power grid are usually much quieter.

    My system uses PV400 PowerVerter inverters, and a BlueSky 3024 charge controller..... and it powers my little remote station without any noticable RFI at all.
  8. WB0RIO

    WB0RIO Ham Member QRZ Page

    Many commercial charge controllers use PWM or MPPT schemes for regulating the solar panel
    current, these use square waves to switch high current DC lines. Much RFI is produced.
    Wiring from the PV panels to the charge controller/battery is typically long and unshielded,
    making for a good RFI antenna. With PWM controllers, little or no RFI will be produced when the battery
    is charging, the controller starts switching and making RFI when it hits the point of regulation.

    Plug: the SCC3 charge controller uses a damped gate control signal on the switching MOSFET to
    greatly reduce the harmonics, see:
    for details.

    KK4NSF is right about DC to AC inverters causing lots of RFI. If you require AC, the inverter *and* batteries
    and associated wiring need to be inside of a Faraday shield and the AC wiring should be run through an RFI
    filter. Off-grid solar installations often have all of the batteries and inverter in an out-building.
    That should be shielded, grounded and far from your antennas.
    KL7KN likes this.
  9. K3RW

    K3RW Ham Member QRZ Page

    Thanks for all the helpful info. I didn't realize that LEDs can cause about as many problems as far as noise goes (!)--but I can definitely see why. The city is slowly replacing all the streetlights here from the orange glow ones to hyperwhite LEDs. Lucky for me the area neighborhood powerlines are all underground.

    I wondered if there was a way to throw a switch on the inverter--you know, to turn it off in case the noise was high when I would run the rig--if that would help. Unlucky me would somehow get stuck with a lousy controller and not know it :eek:

    The proposed solar setup wouldn't be for off the grid, just the run of the mill rooftop thing in a residential neighborhood. Still in the planning stages but maybe at least a year away if it is feasible.
  10. K6MSM

    K6MSM Ham Member QRZ Page

    I installed solar last year and I regret it as respects ham radio. I have very large amounts of RFI from my own system, during the day and possibly some at night as well. I wasn't very active in ham radio when I installed it and now I am again. The noise is on every band from 80m to 2m. Perhaps there's a newer thread I should post on. This one came up on a search.

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