Larry, W0QE, and I developed the filters for the grow light ballast
because of a neighboring grow light setup down the street. I persuaded
the grower to lend me his setup for a day and Larry and I tried various
filters. This is by no means a fix for every ballast, but they are
similar enough that it is a good place to start. We discovered a
combination differential and common mode filter on the AC side along
with a common mode choke on the lamp side works well. The common mode
choke on the lamp side should not include the third wire for best
results. You can probably find a commercial filter from Corcom or
Morgan Mfg. for the line side but you will have to make the filter for
the lamp side. We used #31 material for the core. The system we tested
used a 1000 Watt bulb, so the core has to be sufficiently large so that
it does not get too warm with the large amount of common mode current
that it must choke. Larry's web site , http://www.w0qe.com shows
bypass capacitors on the lamp side filter, but we found the lamp would
not start with those capacitors installed. We were able to purchase
the pigtail adapters at a hydroponic store. I did a before and after
comparison with my IC-7000 mobile installation on 40 meters while
sitting in front of the grower's house. The RFI went from S-9+40 dB to
S-5 after the filters were installed. Total price of the parts was
about $60.00.
40 and 30 meters seems to be the bands most effected. I believe this is
due to a "sweet spot" existing between the antenna factor of the house
wiring and the harmonics of the ballast. The energy in the ballast
harmonics decreases with frequency but the antenna factor increases. I
think 40 and 30 meters is the crossover point.
As far as the FCC is concerned, at least here in the Denver area, they
are not much help. Due to budget cuts and the direction largely having
to come from the Washington office, I have not found that avenue
productive. I had a long telephone conversation with Laura Smith, and
whereas they are beginning to recognize the problem, I do not think any
solutions will be forthcoming soon if at all.
I have tracked down three grow situations in the last month. I am
finding it to be almost impossible to stay on top of it. This makes
nine in the past few years. I have found in some cases, if the property
is a rental, getting the landlord involved can work.
We are losing this battle because most of these electronic ballasts are
being imported with no filtering and some with bogus FCC stickers.
Since recreational marijuana has become legal in Colorado and the
federal government has agreed to turn a blind eye, I don't see much hope
on the horizon. With legalization, perhaps some rules can be
implemented on the local level for some inspection. We may be able to
get an in that way so we or the inspector can recommend some filtering.
Enough of my rant. I hope some of this is helpful.
73, Tom W0IVJ
On 9/27/2013 1:31 AM, Jim Brown wrote:
On 9/26/2013 11:00 PM, Ron, K6KYJ wrote:
My old friend is back.
Hi Ron,
One of the members of this reflector, W0QE, is a veteran EMC
specialist, has done extensive work on RFI from grow lights, and has
developed solutions. I suggest you chat with him, acquire/build
suitable filters, and approach your neighbor telling him you don't
give a shit what he's growing or what he does with it, but that his
lights are making your life impossible, and you would really
appreciate it if he would stop making your life miserable by fixing
his noise, and that installing your filters would be a great way to
start.
73, Jim K9YC
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