Charly wrote:
Hello Yerodin,

Did you check the same frenquencies with the Sony radio ? (the previous posts do
not mentioned such try). If you have the whistle on the Sony too, the problem is
not in the radio.

About the antenna, you can give a try to a very simple antenna :
- coax feed line maid out from a piece of TV coax
- two thin wires, one connected to the center line of the coax,
the other connected to the shield.

You extend the two wires in opposite directions and it makes a portable random
dipole. Mine is about 5m fully extended, just because I had this length of wire.
No computation or studies to match specific frequency or having right impedance.
In buildings made of iron structure, I put it on a window with adhesive tape, or
let it hanging outside, trying to keep the two wires apparts.

This greatly improved my reception on all bands. I must say I tried mainly in
the lower bands in frequency (F = 15000 kHz) since I'm mostly listening at
night. MUCH BETTER than the piece of random wire.

I'm interested in your experience since I'm planning to buy this Kaito 1102 some
day as a smaller travelling radio than my current Sangean 909.

Charly

Thanks for responding Charly,

I did simultaneously check the same frenquencies with the Sony radio...
and there was no whistle (i.e. mosquito buzzing) noticeable from the
Sony.

I do greatly appreciate the instructions on building the "portable
random dipole", & will save what you said and try it later.

FYI, I have been researching what some radio websites call a
"broomstick antenna".

It basically consists of a length on non-conductive form (e.g.
broomstick or PVC conduit), around which a number of turns of wire are
wound.

Technical information (i.e. that made sense to me) was initially scarce
until I found this gem:

" Wound on a 3 foot length of PVC pipe, the long loopstick antenna was
an experiment to try to improve AM radio reception without using a long
wire or ground. It works fairly well and greatly improved reception of
a weak station 130 miles away.

A longer rod antenna will probably work better if space allows. The
number of turns of wire needed for the loopstick can be worked out from
the single layer, air core inductance formula:

Inductance = (radius^2 * turns^2) / ((9*radius)+(10*length))

where dimensions are in inches and inductance is in microhenrys.

The inductance should be about 230 microhenrys to operate with a
standard AM radio tuning capacitor (33-330 pF). The 3 foot PVC pipe is
wound with approximately 500 evenly spaced turns of #24 copper wire
which forms an inductor of about 170 microhenrys, but I (i.e. the
author) ended up with a little more (213uH) because the winding spacing
wasn't exactly even.

A secondary coil of about 50 turns is wound along the length of the
pipe on top of the primary and then connected to 4 turns of wire wound
directly around the radio. The
windings around the radio are orientated so that the radio's internal
antenna rod passes through the external windings.

A better method of coupling would be to wind a few turns directly
around the internal rod antenna inside the radio itself, but you would
have to open the radio to do that. In operation, the antenna should be
horizontal to the ground and at right angles to the direction of the
radio station of interest.

Tune the radio to a weak station so you can hear a definite amount of
noise, and then tune the antenna capacitor and rotate the antenna for
the best response."


Quoted from Mr. Bill Bowden's web site, on which there is also a
pictu

http://ourworld.compuserve.com/homep...wden/page2.htm


Although I didn't see any reference to using the radio's external
antenna jack, I was grateful for:

1. The entire explanation.

2. The explanation that an antenna tuner, is a a standard AM radio
tuning capacitor. (he included values)

3. The diagram.

4. The formula.

For my dad's radio, I plan on combining this information with data from
these two websites:

http://www.hard-core-dx.com/nordicdx...al/broom3.html

http://www.hard-core-dx.com/nordicdx.../bromstik.html



I will build one for myself, whenever I figure out what's the fix for
my KAITO 1102.

Kindest regards,
SW Newbie
Yerodin P.