[RFI] Fishtank Lighting RFI on 3.8 and 1.8Mhz

Bob Tellefsen n6wg at earthlink.net
Sun Nov 23 17:27:22 EST 2003

>From your description, it sounds like switching power supplies used to power
the UV tubes.
I'd suggest some ferrite cores on the ac cord right at the power supplies.
See if that at least knocks down the RFI level.
73, Bob N6WG

-----Original Message-----
From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com]On
Behalf Of K1ZM at aol.com
Sent: Sunday, November 23, 2003 2:32 PM
To: rfi at contesting.com
Subject: [RFI] Fishtank Lighting RFI on 3.8 and 1.8Mhz

Hello out there.

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
a large aquarium.  Apparently a combination of ultraviolet and white light
makes algae grow on the rocks and helps the plants survive - and these
must be on for about 6 hours daily.

The offending signals sound somewhat like TV birdies and are quite
unstable -
with the most offensive RFI occuring around +/- 3.8Mhz and on +/- 1.830Mhz.
These signals drift back and forth - sometimes slowly but more often quite
erratically.  One moment they will be on 3803 and then they will be present
low as 3795.

The specific system I am dealing with has ACTINIC WHITE - VHO-1 and SUPER
ACTINIC R - VHO - 1 (ultraviolet light) bulbs in it - 2 each/ 4 total and
twin power supplies of sorts supplying the voltage to the lamps.

The bulbs (which look like very long fluorescent tubes) are made by
Ultraviolet Resources International - and are quite expensive - around $100

Powering off the units kills the birdies COLD - and they definitely reappear
as soon as the unit is turned on again.

As this one is totally new to me, I am unsure how to proceed.  Has anyone
ever seen this one before?  What type of fix will work and where should it

(Yes, I know three sticks of DYNOMITE in the right place will solve my
problem - but this guy is a friend and I am trying to find a solution that
works for
both of us.)

Any ideas out there?

Sure would appreciate some help with this one.

Many thanks.


K1ZM at aol.com

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