[AMRadio] "Magic" lamp QRM

[Tommye & Jim Wilhite]

Don:

I remember several years ago about some company that designed a lamp like
that, but don't remember all the particulars.  Back in the 80's I had a
friend that had a lamp that the switch was touch sensitive, and if my memory
serves right it was an add in device that screwed into the base of the lamp
then the bulb screwed into the device.  You would leave the switch turned on
and it sensed the touch of your hand to the base of the lamp.  There was
also some company that developed a bulb that ran in the 14 meg region.

Could this lamp be something one of the companies shelved years ago and now
has redesigned and/or reintroduced or do you have any additional information
about it?  It seems the price of the lamp that had that kind of switch
integrated was so expensive that they didn't sell many so it disappeared
from the shelves.  I don't remember the frequency of the thing but thought
it was higher than you reported.  Again if I remember right, the cap effect
of your hand on the lamp base changed frequency of the oscillator in it
which caused the lamp to go off/on.

Sorry I don't remember who built or sold them, sadly it has been too many
years.

73   Jim
de W5JO





>
> I recently noticed a very rough, broad signal that wipes out 30-kc
portions
> of the spectrum from the middle of the broadcast
> band through 10 m. It is especially bad on 160 and 80m. I did a little
> sniffing with a portable radio and found the source to be a
> table lamp my daughter just bought. The thing doesn't have a conventional
> switch, but a metal base, and you turn in on and off
> by touching the base with your hand. The thing must have some sort of
> oscillator somewhere in the 450 kc range, and works by
> detuning the oscillator when you touch it. What kind of rubbish is someone
> going to think of next to garbage up the radio
> spectrum!
>
> I have never seen one of these things before. Is this a novelty or
> speciality item, or is this the way all table lamps are made these
> days? (This was probably the first time in over 20 years since anyone here
> brought home a new table lamp.) Surely, this must fall under Part 15, so I
> wonder why the FCC even allows those things to be sold on the market. The
> noise is far worse than the hash from my computer monitor, and I thought
> that was already bad enough. I'm surprised the AM broadcast industry isn't
> raising bloody hell about stuff like this. I can't imagine polluting the
rf
> spectrum with rubbish because someone might be too lazy to flip a switch
on
> a table lamp.
>
> I'm wondering if anyone else has had problems with interference from those
> things, and what might be the simplest solution. I tried an in-line rf
> filter, but it made no improvement whatever. Unless there is something
> simple to by-pass, the only solution I can think of is to go into the
thing,
> rip out the electronics, and mount a conventional swith with a knob on the
> base. I'd like to hear form anyone who has successfully fixed one of these
> things some way other than clip-leading the power cord across the HV
> terminals of the plate transformer and throwing the big switch.
>
> Don K4KYV