Topband: "Magic" lamp QRM

[Keith Jillings]

Donald Chester wrote:

> I recently noticed a very rough, broad signal that wipes out 30-kHz 
> 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 kHz 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 was given one of these some years ago, and took it to our "place in the hills" 
where I don't usually operate.   Up there, we have a cordless phone:  whenever 
the phone rang, the thing would turn on and off!

Then, last year, I took the HF rig up there and worked on 160 over Christmas. 
I found the thing gave off a little QRM, but before I got round to tackling it, 
I found it switched on and off at every dot or dash...    Wife thought it was 
having a fit.

Anyway, the switching gave up with a muffled PHUT! a few minutes later, and was 
removed and replaced by a standard switch in the lead.   Everyone's happier.

-- 
Keith Jillings
G3OIT   GW3OIT   G-UTSY at EGMC