fluorescent lamps interferance

[chuck]

Hello David,

What radio reception are you concerned with?

Interference from the switch-mode power supply in the lamp
fixture could be radiated, or it could be getting to the
radio through the 12 volt circuit.

RadioShack ferrites could help, but I think we need more info.

Chuck

 

[chuck]

Ok, then the interference is being radiated. Take the radio
out on deck and see if the interference drops to an
acceptable level when you are 10-15 feet from the lamp. If
so, then the answer may be to use an external antenna.
Nothing elaborate is necessary. Maybe a twisted pair from
the radio antenna jack to the antenna would help cancel any
radiation from the lamp to the feedline.

Can't think of anything else to try that wouldn't be "over
the top". Someone else may have a better suggestion.

Good luck, David.

Chuck

 

[Doug Dotson]

I'd say that turning off the flourescent lights when using the radio is the
simplest solution. Install an indandesent for use during those times if you
need light at the rig.

Doug

 

[david]

Hi all
Is there an easy soloution to stop the interfrence that florescent lamps the
12volt ones from tandy/dick smith cause to radio reception.
thanks
David

 

[david]

Hello Chuck
Thank you for your reply.
Its just an AM/shortwave reciver it makes no diffrence if it works from the
ship supply or the radios internal batteries.
the florescent lamps internals are a transformer a switch a transistor on a
heat sink 3or 4 capactors and a diode which i disabled to avoid the .6volt
drop that seemed to reduce the interfrence a bit (i think).
the above is from memory I'd have to open one up again to be more accurate.

 

[Me]

Hi all
Is there an easy soloution to stop the interfrence that florescent lamps the
12volt ones from tandy/dick smith cause to radio reception.
thanks
David

that's an easy question....the answer.....TURN THEM OFF.......



Me

 

[Bruce in Alaska]

OK guys...its sea story time! After several years of fighting florescent
desk lamps in US Navy HF receiver sites (110 VAC versions) using the turn
them off, get them out the building policy, I was shocked to see a new
construction building in Alaska having florescent fixtures being installed
in the ceiling. Not only that, but the Naval Research Lab was supplying the
fixtures as GFE (government furnished equipment). This was in 1970 and I was
very surprised to find out there exists special ballasts and fixtures for
florescent lights in radio reception areas. The diffuser cover over the
tubes had a very fine wire mesh laminated into the translucent material and
grounded to the fixture case. We powered up a fixture in the building and I
used a Stoddard NM25 RFI meter and swept the HF spectrum. The fixture was
quiet with the diffuser in place, and fairly quiet with the diffuser open.
Bottom line--there are at least 110VAC RFI reduction fixtures available. I
have no idea what the taxpayers paid for them.
73
Doug K7ABX

There are RFI eliminators that can be added to florescent lighting
fixtures, as an after-market upgrade. GE made all the ones that
I had installed in every Cannery Office in alaska. This was before
the advent of computer networks in the offices, and when that happened
we moved the radio's and antennas out away from the offcies and clear
out in the brush, and just left the Control Heads, back in the plants.
SEA 322's, 330's, and 325's work really well, at the end of 3000 ft of
telephone wire.

Bruce in alaska there is always a way to fix a problem, if money
isn't a part of that problem......