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Author Topic: RFI-Part 2--The touch lamp  (Read 2073 times)

Posts: 10

« on: May 27, 2001, 12:21:05 AM »

Having recently picked up the HAM hobby while simultaneously raising two perfect daughters, 3 and 5, is a fairly large challenge.  But what makes it even tougher is when I am tranmitting at night (the only time I can) on 30 meters (a band that just seems to work very well for me)on CW, and the touch-sensitive lamp in their room cycles through its settings.

For instance, tonight I was in the middle of a perfectly nice QSO when the lamp in their room first went to full brightness, waking them, then to the off position, causing them to call me immediately!
This is no way to operate.

Will winding the lamp power cord around a ferite core help?  Any other ideas?



Posts: 692

« Reply #1 on: May 27, 2001, 07:19:15 AM »

 I was tracking down noise on my receiver. The noise was on all bands. I started turning off one circuit breaker at a time at the house electrical distribution panel. When I turned off the circuit breaker that was supplying power to the touch lamp, the S7 noise dropped to S1. The lamp was not even in the 'on' state, can you believe this! My daughter wanted the lamp which she took back to college. The next day she received an electric shock from it. Either modify with a switch or toss the hazard out. Mabby these lamps will get some bad press on 20/20 or Primetime TV. Jim

Posts: 37

« Reply #2 on: May 27, 2001, 07:38:02 AM »

Same here as N8FVJ absolutely terrible noise across the band particularly 80m with me,was an swl at the time and nearly missed getting into ham radio because of it thinking that my qth was just too noisy,found it by accident one day,like N8FVJ it radiated s**t even when it was off,was able to convince rest of household that it would be OK as a permanent lamp ,so took snips and screwdriver,cut out guts and fitted in-line switch.
Its actually quite a nice looking lamp and no problems now!!

73 de Noel

Posts: 984

« Reply #3 on: May 27, 2001, 04:28:31 PM »

Touch lamps are notorious for generating RFI at the frequencies we use as well as many others. They are covered under FCC rules which allow for radiation below a certain limit. Unfortunately for us, that limit in our our home is within our own receiver's distance.  They, like wall switch reostats are real noise culprits. I refuse to allow them into my home due to their noise levels. The lamps are ALWAYS on like the TV and other units that use remotes to "turn them on". They are never off. The electric companies are now asking people to put those types of appliances on switchable extensions and turn them off when not in use or put them on an outlet that can be turned off. They are using power even we aren't using them.
 I also found that the switching power supply I use for my own IC-706 generates noise at certain frequencies - notably on the AM radio portion that I listen to sometimes.  I hunted all over my house looking for the noise and finally switched to an older non-switching supply and the noise went away. They are now another noise culprit we need to deal with. Good luck.

Posts: 4431

« Reply #4 on: May 28, 2001, 09:06:45 AM »

Please see my reply in Part I.

A 136' Off-Center Fed Dipole will NOT work on 160, 30 or 15 Meters and I've had no RFI problems on 75, 40, 20, 17, 12, 10 or 6 Meters. If you want to try a coax feed, scrounge up a 4:1 Guanella "current" balun and hang it at the feedpoint then run 50 ohm coax to the rig. Wire dimensions are 45' 6" on the short side and about 136' overall. I started at 140' and (slowly) pruned the long side only until the bands dropped in where I wanted them. I'm no-tune everywhere except the top & bottom of 75/80 Meters and the internal tuner handles that.

The antenna does not work on 160, 30 or 15 Meters.


Brave Helios, wake up your steeds.  Bring the warmth the countryside needs...    

Posts: 4431

« Reply #5 on: May 28, 2001, 09:47:28 AM »

Here's an alternative for you: The All-Band Doublet.

132' across the top section fed with 66' of 450 ohm ladder line to your antenna tuner. Just remember there's 66' of wire from all points on the center insulator. If you can manage it, this could cure your RFI problems on 30 and 15 Meters...

Brave Helios, wake up your steeds.  Bring the warmth the countryside needs...    
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