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Author Topic: halogen lamp switching power supply rfi -solution-  (Read 2684 times)
KA7GKN
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Posts: 147




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« on: April 17, 2003, 12:41:14 AM »

Hi gang, this is slick! I have a halogen under shelf light system. It's 3 20w bulbs and a 75w switcher power supply. The damn thing has been intermittent since day one..however, when it works it's fine EXCEPT... tonight I had the lamp assembly in the radio room and turned it on, Oh MY the rfi/qrm across the band. The Icom IC775dsp noise blanker did nothing not a thing!!!! I then turned on my timewave ANC-4 a little tweeking and poof silence the switcher noise is gone! in A.M. or SSB modes gone quiet I did on/off testing and behold the ANC-4 can and will get rid of the noise.

I suspect though the noise generator being near the ham gear does improve the operation of the ANC-4

So, what did this teach us?
1. any switching power supply no matter how small or packaged will cause interference. Be aware some items using wall warts are actually switching power supplies and not just a tiny transformer type power supply!
2. most radio noise blankers will not eliminate or squelch switching power supply noise
3. the TIMEWAVE ANC-4 does indeed work to eliminate this type noise even though it requires some tweeking.
4. Eliminate the noise at the source! tomoorow I'll go the Home Depot or Lowe's and purchase some sort of small incandescent shelf lamp system.

I hope this helps someone hunting down their mystery noise on HF

regards, Marty   ka7gkn
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KA7GKN
Member

Posts: 147




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« Reply #1 on: April 25, 2003, 12:29:42 AM »

Here is a follow up on the halogen lights and noise...yep it's real! I replaced the 3 20w =60w under shelf system 12v/20w with a slick 120v 20w x3=60watt 3 bulb lamps system. the 20w 120vac lamp system from lowes works well bright and dim and no noise!]
3 lamp system about 39 bucks but really well made!

so all is great yes? no!
In the den I installed a long time ago the individual
12v 20w lamps systemeach lamp is in its own housing then all are wired to a yep! you guessed it a switching power supply. Today I turned them on and wow! the noise covered the band and the anc could not eliminate it since it, the switching power supply, was not close to the sense antenna!

tomorrow I'll replace the bulbs with 120v20w ones and eliminate the power supply.
I'm now confident if anyone has halogen track lighting in their home and find their reveivers plauged with high noise [buzzing] levels try unplugging the power supply, as sometimes turning them off is not really off.

I hope this helps in your search to reduce locally produced noise

regards, Marty ka7gkn
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