Removing/shielding RF noise from 12V Fluros

Submitted: Friday, Sep 26, 2003 at 18:21
ThreadID: 7456 Views:2252 Replies:8 FollowUps:11
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Whilst the subject of RF interferance is being discussed, have any of you worldly experienced 4WD-ers got any ideas/suggestions on how to remedy the following:

The 12V fluros inside my Troopy camper, when switched on, turn the AM/FM & SW radios into screeching, wailing banshees.

I have made a few enquiries and all the answers seem to be along this line.

"well these type of fluros are 12Volters, which are made as cheap as possible and the R&D required to silence them is just not justified".

I am wondering is that is the end of the road or is that just 'a blind you with science' type answer.

If the fluros in the house don't dick with the radios, then I am sure there must be something that can be done with 12V ones.

Sooooooo! does anybody have any suggestions.

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Reply By: Member - Wherethehellawi - Friday, Sep 26, 2003 at 18:58

Friday, Sep 26, 2003 at 18:58
Just asking for info sake...
are the 12v fluros like the 12v work light that is rubberised or are these a smaller fluro that are used to replace conventional interior type lighting?...
If its not the 12 v work light type try one and see if it interferes. does it happen if connected directly to battery?
Just adding food for thoughtWow! am I cute
If yer ain't fishing, Yer ain't livin
AnswerID: 32135

Follow Up By: Member - Ken - Friday, Sep 26, 2003 at 21:27

Friday, Sep 26, 2003 at 21:27
Thanks for the reply.

They are the fixed fitting sort and I have used a 12V workshop fluro around the vehicle without any interferance.

Whatever it is, is just a bitch.

I am going to try a television next to see if they interfere with that.


FollowupID: 22939

Reply By: Eric - Friday, Sep 26, 2003 at 21:56

Friday, Sep 26, 2003 at 21:56
I have made a fluro with a stianless steel mesh cage which also protects the lamp and the power is fed to it via a piece of coax, the unit still makes a little interferance but is heaps better. My next light will be a LED type. ERic.
AnswerID: 32144

Follow Up By: Member - Ken - Saturday, Sep 27, 2003 at 12:12

Saturday, Sep 27, 2003 at 12:12

Thanks for the the feedback.

It's obvious that you have experienced the same problem and your 'fix' is interesting to say the least.

Good old Aussie lateral/inventive thinking at its best.

I still believe the real answer lies with the Electrical Engineering R&D 'Einsteins'.

Funny thing about this whole thread is that you and I seem to be the only ones in the whole of Australia experiencing this phenomenon.

Makes you wonder what all the others use for 'lighting sources'.
FollowupID: 22959

Follow Up By: Member - John - Saturday, Sep 27, 2003 at 22:47

Saturday, Sep 27, 2003 at 22:47
Eric, very interested in your comment about LED lighting, was thinking of using this instead of fluro's, but have not checked it out further. Any information on types etc gratefully recieved.
FollowupID: 22993

Follow Up By: Member - Ken - Saturday, Sep 27, 2003 at 23:33

Saturday, Sep 27, 2003 at 23:33

Mate it looks like there are more than two of us who are game enough to 'fess up' to having this problem.

I two would be interested in your idea/s on LED lighting.


Ken Robinson
FollowupID: 22995

Reply By: Member - JEFF - Saturday, Sep 27, 2003 at 14:51

Saturday, Sep 27, 2003 at 14:51
I think your problem is unique. i purchased a cheap interior fluro lite from Supercheap Auto. duel tubes 8 watts each cost about $32. works fine ,no noise , 3 years old with 2 simpson desert crossings Maybe you should change fluros
The alternative is RF supressors avialable from Jaycar Electronics
AnswerID: 32180

Follow Up By: Member - Ken - Saturday, Sep 27, 2003 at 23:39

Saturday, Sep 27, 2003 at 23:39

Thank you for taking the time to reply.

If you have continued to watch this thread you will have no doubt by now seen that I am not a lone ranger here. Thought I was for awhile though.

Anyway, I checked out JAYCAR on the NET an found that they sell a different interior fluro to the ones I have.

So I will check it on Monday and use the information supplied by others on the forum to see if it has one or two diodes.

If I can't fix it that way then I'll try some of the other recommendations except for the petrol lamp as I am a Diesel freak.


Ken Robinson
FollowupID: 22996

Reply By: ToyMotor - Saturday, Sep 27, 2003 at 16:19

Saturday, Sep 27, 2003 at 16:19
The main reason these 12v fluoros produce a lot more interference than 240v ones is that they run at a much higher frequency. Add to that the significantly lower signal strength for your radio when out bush, and you can get a problem!

There is basically two types of interference - radiated and conducted.* The conducted can be fairly easily stopped by wrapping the cable around a iron powder toroid close to the light, the radiated can be more tricky. The cage idea may help here, especially if it's earthed. I've got a cheap 12v fluoro which is a real bastard for interference, but I had one just as cheap mounted in the back of my old 60 series which was as quiet as a mouse. The petrol light I normally use doesn't interfere with the radio at all ;-)

*Just to keep it interesting, the conducted emissions will also radiate from the cable!

AnswerID: 32185

Follow Up By: Member - Ken - Saturday, Sep 27, 2003 at 23:49

Saturday, Sep 27, 2003 at 23:49

Thanks for the info.

I get the gist of what you are saying, however I am not sure I really understand what a Toroid fix is, and if I did, how I would actually go about it.

In the short term I am going to try and source another brand/type of fluro and see if I can cure it that way.

Good to see another who has experienced this problem.

By the way, the petrol lamp do-da is out as I am a pure diesel man with a touch of LPG to cook with.


Ken Robinson
FollowupID: 22997

Reply By: Eric - Saturday, Sep 27, 2003 at 21:53

Saturday, Sep 27, 2003 at 21:53

The reason some flouros are worse than others is the design of the inverter, the ones that use only one transistor rely on the transformer saturating in order to switch the transistor of, the good ones use two transistors, one transistor is an osilater that drives the power transistor, this unit turns the power of before the transformer is saturated, it is the vertual short cct on the battery when the transformer saturates that generates the rf interferance. Interesting to read other posts where the auther thinks we are talking about audible niose. Eric.
AnswerID: 32197

Follow Up By: Member - Ken - Saturday, Sep 27, 2003 at 23:58

Saturday, Sep 27, 2003 at 23:58

I am with you on this.

In the event that I can't source a fluro with two diodes or one that makes no RF interferance, do you know if an Electronics Tech or a Electrical engineer can modify the ones I have, by adding the additional diode etc.

FollowupID: 22998

Follow Up By: Eric - Tuesday, Sep 30, 2003 at 16:11

Tuesday, Sep 30, 2003 at 16:11
The cct uses two transistors not diodes, the problem is on my list of things to fix, I have a cct and some of the hardware built for a interferance free lamp. In the interem I am using a light that is made from 4 off 5mm ultra bright white LEDs purchased from Jaycar for $15 total, the 4 are simply connected in series on 12 volts if you are running you motor while the light is on there is a risk of damage to the LEDs but if the motor is off the voltage is just right without any resistor. The alternative energy asscosiation based in melbourne are selling 1 watt white Led that is as bright as a 20 watt flouro but I think they are not legal because they exceed the allowable radiation under the laser safety regulations. If the LED was used in conjunction with a difuser to spread the beam they may be ok but I hesitate to recomend them if you have children. The !watt LED cost about $50. Eric.
FollowupID: 23165

Reply By: haze - Sunday, Sep 28, 2003 at 07:56

Sunday, Sep 28, 2003 at 07:56
I have one of the "better" double tube ones fixed in the van and its an absolute screecher! Also the single tube, plug in the cig. lighter type similar result. Thought this was the nature of things, usually use tilley lamps anyway but interested in the remedies suggested
cheers haze
AnswerID: 32213

Follow Up By: Member - Ken - Sunday, Sep 28, 2003 at 12:20

Sunday, Sep 28, 2003 at 12:20
There you go Haze, you learn something every day, well I do anyway.

With a bit of luck and all the free and open advice that has been provided by contributors to this forum I/we might be able to solve this vexing problem.

I intend keeping at it until I can get battery powered lighting that is RF free (noiseless).

If and when I do I'll chuck a post on and let you all know.

You wouldn't think it could be that hard to fix. (maybe it is )


Ken Robinson
FollowupID: 23009

Reply By: Member - Timothy - Sunday, Sep 28, 2003 at 09:44

Sunday, Sep 28, 2003 at 09:44
LED tecnology is going ahead in leaps and bounds
as a couple of people have already mentioned.

I'm no expert, but seems they use a fraction of the
power draw of a floro or halogen light.

Bias Boating has a small range
but for the real "cyber-campers" out there
check out the Alternative Technology association (ATA)

look for Luxeon LEDs.

They publish ReNew magazine
which is usually a good read
and can be found at your newsagency
or hopefully library.

(I'm in the middle of setting up a backup solar power
system for our house up here in the Blue Mountains.
I think its going to be a long hot summer
with bush fires, power cuts etc
and I'm going to be the one with cold beer
in the camping fridge and the lights still on.)

Timothy Defender Extreme
AnswerID: 32221

Follow Up By: Member - Ken - Sunday, Sep 28, 2003 at 12:34

Sunday, Sep 28, 2003 at 12:34

Mate, you may have come up with a winner here. Thanks for the info.

I just had a look at the ATA website and noticed that they are in Melbourne where I am.

Soooooooooo! tomorrow I'll give them a call and possibly go and have a look.

I'll keep you posted as to how things pan out


Ken Robinson
FollowupID: 23011

Reply By: haze - Sunday, Sep 28, 2003 at 16:39

Sunday, Sep 28, 2003 at 16:39
Ken. Further to my comments I have radically altered the elecs. of our van to use 20w. halogan lamps. At under 2amp. draw they are a terrific reading light. Also have one rigged on a multi swivel which clamps to an upright on the tray canopy frame. This can be directed onto the fire or barbeque while cooking, then onto the table whilst eating. (Our van is basically for sleeping only, all cooking/eating done outside) But still keen on the fluro solution!
cheers haze
AnswerID: 32230

Follow Up By: Member - Ken - Monday, Sep 29, 2003 at 00:28

Monday, Sep 29, 2003 at 00:28

I've actually got a swivel mounted halogen in the camper as a reading light and know what you are referring to.

We also cook outside when the weather permits.

Now our Troopy camper has a pop-top with the main bed 'upstairs when its made up. When the top is popped its a fairly large area to illuminate.

Sooooooooooo, the good old conversion man installed three of these bastard fluro's.

This week, I will research/make enquires re the LED'S mentioned above in this thread and have a chat to JAYCAR about alternative ones which don't make noise as well as enquire about RF Chokes with them as well.

Once I get some believable answers I will post same on the forum.


FollowupID: 23044

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