My comment was for the FM noise. I guess I should have explained
"capture ratio." With FM, the radio can reject an interfering signal as
long as the desired signal is sufficiently stronger. So for you to get
noise on FM, the noise source has to be very close, or the desired
signal is very weak. I say this only because you have eliminated power
line (mains) noise by going to battery operation. It would make sense
to try the radio that you suspect has a problem in another location to
see if the noise goes away.

Noise on shortwave is another story. There is no ability to reject
noise with an AM radio. Rather, on AM, the noise gets demodulated with
the desired signal. There isn't much you can do other than to locate
the noise source and eliminate it. There are some solutions, such as
going to a loop antenna, which tends to not pick up some types of
noise, or use a noise canceller like the ANC-4. But there is nothing
like finding the noise source and eliminating it.

I have no idea what it is like where you live. In urban areas, noise is
everywhere. My house has it's share of devices that make noise on
shortwave and even AM BCB. I have a laser printer that pumps out
847kHz. Battery chargers with switching supplies are another noise
source. Computer monitors, especially CRT types make noise. Dirty
insulators on power lines. The list is endless.

wrote:
wrote:
Noise on FM is kind of strange due to the capture ratio of the radio,
i.e. it should be reject noise. I'd expect the noise source to be very
close. FM radios aren't hard to find. Try a second radio in the same
location and see if you get the same noise.


wrote:
Hello Everyone,

I am new to SW listening.

The few times I have heard SW, I assumed that the BBC was the only
broadcasting station.

My dad used his SONY ICF-2002, to pick up the BBC news in the mornings.

(So.. I never used to trouble the controls)

Much later, the AC adpter got damaged & he stopped listening to the
BBC. (I believe he mentioned the SONY ate batteries)

It gathered dust for a while, & then I tried using it with an
adjustable, DC voltage adapter & realised there was nothing wrong with
the radio itself.

Since then, I learnt:

1. The BBC isn't the only broadcast station on SW.

2. Signal reception would be improved if I learnt how to build a better
antenna.

3. I should really return the radio w/DC adapter to my dad so he could
listen to the BBC again.


So I bought a Kaito KA1102 portable radio last November 2005.

Initially I was thrilled.

Then after the excitement of owning my own wore off (i.e. about a month
of SW listening), I suddenly noticed that whether operated on battery
or Adapter:

1. A high pitched whistle on the local FM station.


2. A warbling, high pitched whistle on the SW bands.

NOTE:
I am resident in South America.

Within my neighbourhood, two people use broadcasting radio sets to
contact their inland business operations & two taxi service bases
operate near my home.


The whistle is sometimes so loud that it overpowers the voice tones of
the announcers... which is very annoying.


The manual didn't say anything about high pitched whistles, and I have
tried moving to different locations at home (i.e. where I got good
reception before), all to no avail.

Fortunately, it doesn't happen all the time during a sitting, so I just
turn the radio OFF, pause for a bit and then turn it back ON.

That works.... for a short while.


I would really like to understand what causes this problem in my KAITO
KA1102 and what I should do to correct it. (i.e. Preferably before I
return the SONY to my dad)


I believe that if I can resolve this problem I will have a great
portable radio.

My dad's SONY ICF-2002 has been around for years, and except for the
adapter issue and some whip antenna wiggle, gives no trouble today.

Your suggestions on my KAITO 1102, (i.e. besides shipping it back to
the Manufacturer's) would be most helpful.

Kindest regards,
SW Newbie,
Yerodin P.

Hello ,

Thanks for writing in.

I am unsure of what more competent SW radio fans call "noise".

A "whistle, that sounds like a mosquito buzzing in my ear" is something
I can relate to.

What does noise sound like?

Kindest regards,
SW Newbie
Yerodin P.