We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: Rolling QRM - Grow Lights RFI?  (Read 659 times)

Offline ultravista

  • Jr. Member
  • **
  • Posts: 67
    • View Profile
    • Email
Rolling QRM - Grow Lights RFI?
« on: June 02, 2018, 1736 UTC »
https://youtu.be/4XyqMayYElc

Rolling QRM. It starts fast, slows, then stops. When it stops, the interference is present for 12 hours. Some have suggested this is Grow Lights RFI.

The fast rolling begins at roughly at the 2 minute mark

It lasts approximately 5 minutes before stabilizing, just like the ARRL states.

http://www.arrl.org/grow-light-rfi

Grow lights tend to exhibit several unique and identifiable characteristics. So far, they typically produce a broad band noise, particularly across the 40m band. It propagates over much greater distances than one might expect from devices that meet the applicable FCC limits. Other clues include:

  • Generally grow lights are set by a timer for 12 hours on and 12 hours off but this can vary

  • Once you have established the turn on time, listen to the noise as the lamp turns on. Itís generally noisier with less of a flat spectrum. This generally lasts about 5 minutes until the lamp is warm

Now ... how do I locate the source in a densely populated neighborhood? Homes, homes, everywhere ..

Offline Pigmeat

  • DX Legend
  • ******
  • Posts: 4428
    • View Profile
Re: Rolling QRM - Grow Lights RFI?
« Reply #1 on: June 02, 2018, 2352 UTC »
Check my post on the other thread. Do an online search of county and state permits for legal grows in your area. If one is close, it's a prime candidate. Stay safe as your RF source may be coming from an illegal grow nearby.


Offline n3umw

  • Newbie
  • *
  • Posts: 11
  • Germantown, MD USA
    • View Profile
    • Email
Re: Rolling QRM - Grow Lights RFI?
« Reply #2 on: November 13, 2018, 1723 UTC »
Does anyone know of any way to cure the RFI? I have a 300W light and have to turn it off when listening to the radio. I've tried putting a couple of 31 ferrites on the AC cord at the light and it didn't help at all.
RX: Afedri SDR-net, WJ-8711, Lowe HF-150, RSPduo, AirSpy HF+
TX: Icom IC-718
ANT: W2PM Mini-diamond,  KK5JY LoG, 9:1 23' UNUN
AUDIO: Kenwood HS-5 communication head phones
QTH: Germantown, MD USA

Offline Traveling Wave

  • Hero Member
  • *****
  • Posts: 972
  • WNY
  • Let Radio Furnish The Entertainment
    • View Profile
    • Email
Re: Rolling QRM - Grow Lights RFI?
« Reply #3 on: November 13, 2018, 1825 UTC »
What wattage is the light approved for ?
Did you try changing the bulb to a lower wattage?
Location: Western New York ( Niagara Frontier)
Radio :TS480 with RTL-SDR pan-adapter, HDSDR, Omni-Rig Control,Zenith T/O R600
Antenna: 40m dipole, 20-17-15 meter fan dipole

Offline Josh

  • DX Legend
  • ******
  • Posts: 3716
    • View Profile
Re: Rolling QRM - Grow Lights RFI?
« Reply #4 on: November 13, 2018, 2001 UTC »
Some have found relief from rfi induced by touch lamps by installing ac line rated bypass caps in the lamp, I suppose this would take care of new ones too but might affect their function, dunno.
Conveniently located near Vincennes Indiana.

Offline n3umw

  • Newbie
  • *
  • Posts: 11
  • Germantown, MD USA
    • View Profile
    • Email
Re: Rolling QRM - Grow Lights RFI?
« Reply #5 on: November 26, 2018, 1450 UTC »
Adding caps is a good idea, THANKS! Three .01uF 5kv disk caps between each of the AC lines might help. Probably not room for anything bigger. The "light" is a 300W bank of LEDs.
https://www.amazon.com/gp/product/B00XC3LBI2/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
RX: Afedri SDR-net, WJ-8711, Lowe HF-150, RSPduo, AirSpy HF+
TX: Icom IC-718
ANT: W2PM Mini-diamond,  KK5JY LoG, 9:1 23' UNUN
AUDIO: Kenwood HS-5 communication head phones
QTH: Germantown, MD USA