[RFI] Fishtank Lighting RFI on 3.8 and 1.8Mhz

Cortland Richmond ka5s at earthlink.net
Sun Nov 23 15:34:47 EST 2003


I suspect your friend has electronic ballasts (the "power supplies"). These
are efficient but can generate RFI.
Take a look at http://www.icecapinc.com/pdf/660.pdf .  
This ballast will run up to four VHO bulbs totaling 440 watts. 
http://www.icecapinc.com/pdf/430.pdf is for a 330 watt electronic ballast. 

The specifications sheets mention a maximum mounting distance of 50 feet -
which would be a really good antenna for harmonics of the 22-25 KHz
operating frequency. While I see UL approval mentioned, no FCC compliance
is shown.

The company selling these ballasts and VHO fixtures is Ice Cap and its
contact data is at
http://www.icecapinc.com/contact.htm . 

Suggestions: Locate the ballasts as close to the bulbs as possible. Add
power line filtering at the ballast inputs. Do not modify the fixture.
These are designed for aquariums and will have been built to deal with
water (though they are not waterproof) and you do NOT want to breach
whatever protection ICI designed into them.


> [Original Message]
> From: <K1ZM at aol.com>
> I am trying to remedy some TV birdie-like (or touchlight-like type RFI) 
> is coming from special ultraviolet lighting used to stimulate plant
growth in 
> <SNIP>
> The offending signals sound somewhat like TV birdies and are quite
unstable - 
> with the most offensive RFI occuring around +/- 3.8Mhz and on +/-
> These signals drift back and forth - sometimes slowly but more often
> <SNIP>
> Any ideas out there?

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