Q&A: Is it possable to turn on a touch lamp with a Ham radio?
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Question by 2W615: Is it possable to turn on a touch lamp with a Ham radio?
My neighbor is telling me that Im turning on their touch lamps in their home when I operate my ham radio gear, I know Its probably posable if I was close to the frequencey that the lights operat on but Im only running on the 10 meter bands, wich is only 28Mhz area.
Best answer:
Answer by Patrick B
Over the years, many different properties of the human body have been used to flip touch-sensitive switches:
* Temperature - The human body is generally warmer than the surrounding air. Many elevators therefore use buttons that are sensitive to the warmth of the human finger. These buttons, of course, don't work if you have cold hands. The motion-sensitive lamps you see on people's patios also sense the heat of the human body.
* Resistance - The human body, being made mostly of water, conducts electricity fairly well. By placing two contacts very close together, your finger can close the circuit when you touch it.
* Radio reception - You may have noticed that, when you touch an antenna, the reception gets better on a TV or radio. That's because the human body makes a pretty good antenna. There are even small LCD TVs that have a conductive neck strap so that the user acts as the antenna! Some touch-sensitive switch designs simply look for a change in radio-wave reception that occurs when the switch is touched.
Touch-sensitive lamps almost always use a fourth property of the human body -- its capacitance. The word "capacitance" has as its root the word "capacity" -- capacitance is the capacity an object has to hold electrons. The lamp, when standing by itself on a table, has a certain capacitance. This means that if a circuit tried to charge the lamp with electrons, it would take a certain number to "fill it." When you touch the lamp, your body adds to its capacity. It takes more electrons to fill you and the lamp, and the circuit detects that difference. It is even possible to buy little plug-in boxes that can turn any lamp into a touch-sensitive lamp. They work on the same principle.
What do you think? Answer below!
Yes, possible.
The power level could be over driving the touch circuit (even if the wrong freq) Consumer electronics are notorious for not being shielded very well to RF.
Just because the neigbor “thinks” it is you, it does not prove it is you. Have you done any testing to verify? If so, try turning down your output power to see if that helps.
It may be. Frankly I’d never really heard of anyone using touch lamps before, but according to this link, some of the touchlamp switches depend on a change of frequency, such as would be caused by the touch of the human body, to change the setting from the off setting to the on setting.
It sounds to me that it would have to be something like the way an IF works, you know, how an IF of 5 MHz will take an incoming signal of 3.700 and change it to 8.700? If this is happening, perhaps the switching device, which apparently does use an antenna, is interpreting the signal at between 28 and 29.7 somewhere, as equivalent to the touch of a human being. If you were on CW, I imagine it would be particularly annoying, if the switch was responding to the keying.
If you think this is the case, you can test it where you are transmitting (low power, you’d need to use a small vertical for this, I think, and even at 10 meters, 100 watts won’t do anyone any good in an enclosed space) , and no other living creature is near the lamp, not even someone’s dog, and pressing the mike button turns it on, it may be the case. If it is, you could try using a toroid core, like you can get at Radio Shack, and wrapping the line cord around it a few times, and thus change the resonant frequency of the line, and maybe resolving it that way.
You’ve no doubt heard of the ham opening and closing his neighbor’s garage door by keying his rig. Hopefully, your neighbors may have heard of this too, and jumped to the wrong conclusion.
If the switch is confusing a 10 meter signal as a human touch, despite the interesting resonance problem, I suppose loading up a neighbor and trying to work DX would be a bad idea. Hi.
AB9BD
yes it is. sometimes when i turn on my bathroom fan, my bedroom touch lamp turns on!