[RFI] Nineteen Hour Noise

[tlthompson]

Ron,

I have tracked down several grow light noise sources in my neighborhood 
that fit your description exactly.  The noise in my case was generated 
by 1 kW ballasts used with high pressure sodium lamps.  In one case I 
was able to borrow the light system from one grower for a day.  W0QE and 
I spent 8 hours developing filters on the lamp side and AC side with 
good success.  See 
http://www.w0qe.com/RF_Interference/grow_light_electronic_ballasts.html 
for details.  In both of my cases, the growers were growing marijuana so 
be careful when you approach them after you find the offending source.

Good Luck,
Tom   W0IVJ

On 3/7/2013 9:43 PM, Ron, K6KYJ wrote:
> I have a unique RFI situation that first surfaced within the past thirty days. The interference is a very constant buzz saw type noise, without pulse and with constant amplitude. It is strongest at 7.0 mHz with a peak of S9+10 received on an Icom R71A (my RFI search rig). The signal peaks at S9 on an Elecraft K2.
>
> There are two confusing (in my perception) variables.
>
> The noise ceases every day at precisely 12:23 p.m. local time. It is an instant on/off cessation. This would suggest that the source is controlled by a timer.
>
> The noise resumes every day at precisely 6:25 p.m. Here is where it becomes interesting. At the edge of my property is a new Pacific Gas and Electric (PGE) LED street light. It would seem that the street light comes on simultaneously with the noise.
>
> [My next step to confirm the light/noise association is to set up a video camera with sound linked to a receiver.]
>
> The timer aspect makes me suspect grow lights on a timer.  This is a real possibility. The concurrence with the street light coming on points at a LED power supply issue.
>
> (For the record, I have read all of the previous threads re grow lights. I would prefer not to enable further discussion of the legalities of herbal agriculture; in my neighborhood, until recent regulations became law, there were at least fifty (CA) Prop. 215 medical marijuana grows within a mile of my QTH.)
>
> A complaint has been filed with PGE and I have been promised direct contact “within five working days”.  Our mutual approach will probably be a path of eliminating suspect locations. In the past, PGE has been very cooperative in resolving issues with the older streetlight photocells and with 12 KV cut out fuses.
>
> I will return to this thread when more information develops.  Right now, I have a five hour window for noise-free radio operation.
>
> Ron K6KYJ
> Chico CA
>
>
>
>
>
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