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