RadioBanter - View Single Post - Strange Problem With HT

September 25th 04, 10:05 AM

(moth .) wrote in message ...
Just to add to this, I plugged in the toaster, the microwave oven and
several other appliances and the only thing that caused the socket to
buzz when I key the HT is the hair dryer which is on OFF (but not
reset). When I pushed the reset button with the hair dryer still off,
the socket didn't buzz. I would like to understand exactly what
internally in the socket is causing that buzz which is extremely loud.
Does anyone know? Thanks for your responses to my thread.

Hi Moth,
this is indeed a bizarre problem, and by remote control I can offer no
more than a theory - I cannot vouch for its truth without a field
study of the offending apparatus.

The only plausible theory I can see is that the length of the hair
dreyer cord plus the cutout is resonating at your operating frequency
and this energy is being transferred back into the socket causing it
to buzz as its acting as a detector.

The hole in this theory is the amount of RF energy needed to cause
audible buzzing of the AC outlet - it would have to be considerable! -
if this is the case, then anyone in close proximity is getting far too
much exposure to RF energy with possibly consequent negative effects
on their health. I would suggest you move the antenna well clear of
the kitchen.

I did suggest examining the AC outlet - they do fault, particularly in
a kitchen environment because
1.They are used more than any other outlet, with a heavy cycle of
connect/disconnect of appliances. This causes the spring contacts in
the plug to weaken and arc.
2. They get dust/fluff build up from the operating cycle, in a kitchen
with cooking oil in the air, this can cause a conductive path between
active and neutral.

A visual examination usually reveals this, ie signs of overheating
/charring /contact arcing.

I would also check the hairdryer - if the thermal cutouts have
operated, it is usually because the device is clogged with dust/fluff
and has overheated - pull it to bits and clean it, or bin it and buy a
new one - your choice.

I was not attempting to belittle you in any way, Mr NS decided to go
off at a tangent and I foolishly tried to discuss fault finding
methodology with him. You are already doing this with your plugging in
other appliances etc to try and replicate the fault - observation and
experimentation are the basis of ANY field of science. Volta used this
method in inventing the "Galvanic Pile" (aka battery) when he observed
his meal of frogs legs was twitching when his knife came into contact
with them and the pewter plate (with a vinegar dressing - the
elctrolyte) - he observed, experimented, and invented the battery. (a
diversion from this your problem, but hopefully a demonstration of the
"scientific method" - a most useful tool)

73 de VK3BFA Andrew