[K3CAL] RF Interference

[N3AE]

All florescent lights need a ballast to regulate current. 

See http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/adaptableballasts/ballast.asp 

and http://en.wikipedia.org/wiki/Electrical_ballast 

The old style magnetic ballasts typically were not EMI generators unless defective. These days electronic ballasts have taken over the market. Depending upon the design, they can be switching large amounts of current to control the "average current" in a pulse width modulation approach. Rapidly varying (i.e. on/off) signals generate energy at the switching frequency and harmonics of that frequency all the way through the HF bands and beyond. 

In the case of these Lumatek electronic ballasts, the problem is exponentially worse because they are designed to control 1000 watt grow lights .... yes... 1 KW of lighting . Lot's of energy in those switching waveforms. Could it be fixed? Sure. Proper filtering, choice of PWM frequency and a tight EMI enclosure, but that adds to the price of the product. 

In the case of these "unintentional" EMI generators, fielding the product and then asking for forgiveness rather than permission isn't the best policy. 

The Lumatek ballasts probably have a somewhat common spectral signature, so if you know that signature and have the proper equipment (spectrum analyzer) you can probably find out who's growing pot in the neighborhood (and so could the police). Hmmm,,,,have I just generated the seeds of a conspiracy theory ... Lumatek ballasts are strong EMI emitters by design? ;-) 

Shawn 
N3AE 

----- Original Message -----

From: "Rich Weaver" <weaverr at comcast.net> 
To: "K3CAL K3CAL" <k3cal at mailman.qth.net> 
Sent: Saturday, January 24, 2015 10:48:14 AM 
Subject: [K3CAL] RF Interference 

Should you be eligible for this program (or not)... 
Marijuana grow-lights cause problems for ham-radio operators 

The marijuana industry and Uncle Sam haven't been on the same page for 80 years, but these days, in a unique bit of weirdness, it's not the U.S. Department of Justice that could create a problem for pot growers: It's the Federal Communications Commission. 

The FCC regulates the country's electronic communications, which is relevant because it turns out that, bizarrely, light ballasts used in the growing of cannabis emit radio-frequency interference that screws up amateur-radio transmissions being sent by local ham operators, a licensed, legally protected practice. 

In a March 12 letter to the commission, the American Radio Relay League, the national association for amateur radio, complained that interference from grow lights was greatest in the medium- and high-frequency bands between 1.8 and 30 megahertz, and that it comes in no small amount. 

"The level of conducted emissions from this [Lumatek LK1000 grow light] is so high that, as a practical matter, one RF ballast operated in a residential environment would create preclusive interference to Amateur radio HF communications throughout entire neighborhoods," wrote general counsel Christopher Imlay to acting chief of the FCC Spectrum Enforcement Division John Poutasse in the hopes the agency would halt sales. 

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