Excellent presentation on the web site, Tom - very nice.
Looking at your designs, I wonder if a computer power supply input
filter such as the Qualtek 858-03/007 might be a reasonable alternative,
in cases where the grow light user was uneasy about a ham-built unit
(though yours look very professional). It is rated at 110/220VAC 3A,
has 2 x 2.5 mH inductors in serieswith the hot and neutral, and
capacitors across both the input and output (0.1uF and 2200 pF). IIRC
this cost me about $10 and was very effective in quieting a computer
whose power supply had all the filtering components omitted (still shown
on the PC board, but neatly jumpered). I noted (and worried about)
feeding a 450-watt computer supply with this filter, but it runs cold
and has done so for about 4 years, 24 hours a day.
Has anyone done careful tests of these units? It strikes me that, if
effective, something like this could be a cost-effective, low effort
substitute for many home-built solutions.
73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.
On 3/8/2013 5:00 PM, tlthompson wrote:
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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