In article om,
"RHF" wrote:

Telamon wrote:
In article . com,
"RHF" wrote:

Blitz,

Ideally - I should be able to take the little Loop Antenna
that came with the Cambridge SoundWorks # 740 Radio
and Up-Size It + Plus Relocate It to and Out-Side Location
and there-by improve my overall AM/MW Radio Reception.

# 1 - Same Impedance at the Antenna Input Jack from the
larger Loop Antenna as the smaller {Factory} Loop Antenna.
[ Not Tune AM/MW/BCB Wide Band Loop Antenna. ]

# 2 - Larger Loop Diameter {Larger Signal Capture Area}
and Few Turns in the Loop itself.

# 3 - Out-Side Location Stronger RF Signals and less Man
Made Noise then in-doors.

QUESTION - Does anyone with some simple practical ideas
for Loop Antenna Up-Sizing to help fix my problem ?

Snip

Yes. I've posted it many times. Cheap and easy to make with items from
Radio Shack and other places. You can make it out of magnet wire or coax
cable. Do you want a less sensitive shielded antenna or higher gain? As
long as you don't have aluminum siding you can use an exterior wall on
the inside.

Telamon,

I have tried building and using a larger Un-Tuned Loop Antenna
with the Cambridge SoundWorks # 740 Radio several times
with out any sucess.

ORIGINAL AM/MW LOOP ANTENNA :
Eight Turns (8T) of Wire on a 4 5/8 Inch Square Form
with a 51 Inch Twisted Pair of Wires to the AM/MW
Antenna Input Jack. - - - Should be about 17.3 uH

AM/MW Loop Antenna Calculator :
http://www.mindspring.com/~loop_ante...loop_calc4.htm
This original (OEM) Loop Antenna worked barely OK
with the Radio for local AM/MW Radios Stations only.

LARGER AM?MW LOOP ANTENNA :
Four Turns (4T) of Wire on a 14 Inch Square Form
with a 15 Feet Twisted Pair of Wires to the AM/MW
Antenna Input Jack. - - - Should be about 17.5 uH
This Larger AM/MW Loop Antenna did not work at all.

Tried a 51 Inch Twist Pair feed-in-line and a 72 Inch
Coax Cable feed-in-line with this Larger Loop Antenna
with worse results then the original Loop Antenna.

-IF- In fact the Radio is Tuning the Loop then this Larger
AM/MW Loop Antenna should have worked at 17.5 uH
with the Radio's internal circuitry. It Did Not.

You want to make a 1 turn loop and it has to be at least 50 foot in
length. If you have a 12 foot square room you can tack or tape magnet
wire to wall facing the outside will work as long as you do not have
aluminum siding or stucco. A wire mesh nailed to the frame is used to
hold the stucco up.

Use the coax from loop to radio connection.

Then you are down to figuring out the antenna jack. It could be a three
connection stereo or 2 connection mono plug. Whichever it is you have to
get the right two contacts connected to the loop. The spec on the jack I
can find on line just says 3.5 mm and that's it.

The loop is electrically small so it will pick up stations on edge in
the plane of the loop.

I use a loop like this and I get -20 dBm levels for local stations on it.

--
Telamon
Ventura, California