In article . com,
"RHF" wrote:

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


Telamon wrote:
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.


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.


The Plug / Jack is 3/16" Stereo - With the Loop
Antenna wired to the End-Tip and Center-Ring.
Note the Barrel of the Plug /Jack is not used.

So what's going on? You got the loop antenna working?

Does the user manual tell you about the antenna plug connections?


No - I do not have the Larger Loop Antenna Working.
Four Turns (4T) of Wire on a 14 Inch Square Form
- - - Should be about 17.5 uH
AM/MW Loop Antenna Calculator :
http://www.mindspring.com/~loop_ante...loop_calc4.htm
+ Tried Adding a Turn (5T)
- Tried Removing a Turn (3T)
Both were no good.

Yes - The Radio Pamphlet {Manual} refers to the
AM/MW Antenna Plug connections :
http://www.cambridgesoundworks.com/p...dio_cd_740.pdf

Page 5 - Item B-1
Page 11- Back of Radio showing AM Antenna Input
Page 24 - Specifications
One rear panel AM Antenna 3.5 mm stereo minijack
Antenna stereo mini plug wiring configuration
sleeve - no connection, tip and ring - wire loop antenna
- - - That's It - That's All - - -

This is what I have figured out to date :
The External AM/FM Antenna feed-in-line requires a 3/32" Stereo
Plug to connect to the Cambridge SoundWorks # 740 Radio
* RadioRadioShack Catalog # 274-244
http://www.radioshack.com/product/in...ductId=2062449

The Plug / Jack is 3/32" Stereo - With the Loop
Antenna wired to the End-Tip and Center-Ring.
Note the Barrel of the Plug /Jack is not used.

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

CSW - Tried contacting Cambridge SoundWorks a month or two
ago and really could not get anyone there to answer any questions
about the AM/MW Loop Antenna : Tuned ? - Un-Tuned ? - uH ?
- - - Seems like they would have the Info and may be the name
of a Product that would work with their Radio for better AM/MW
Radio reception.

How To Contact Cambridge SoundWorks
http://www.cambridgesoundworks.com/s...=about_contact

Sales and Technical Support
7 Days a week 10AM-7PM ET
U.S.: 1-800-FOR-HIFI
Outside U.S.: 1-405-742-6704
Sales Dept. Fax #: 1-405-742-6678
eMail: Sales & Technical Support
- - - Contact Us (CSW) by eMail
http://www.cambridgesoundworks.com/s...ailsupport.cgi

FWIW - I just sent them another eMail about my
AM Radio Reception Problem and related Questions.


'csw' makes me feel : confused, stupid or wrong ~ RHF

The loop is just made of wire and will be untuned.

The manual shows a monaural plug in the picture but the last page
describes it as a stereo plug and that the tip and ring is used and the
barrel is no connection. Be sure to use the tip and ring connections on
a stereo plug.

You only describe things as no success and that is not very descriptive.
Do you not get any signal with the loop than comes with the radio?
Providing that you do get some stations with the loop that came with the
radio are you describing no success as the larger loop is no better?

Providing that you are getting stations with the loop that came with the
radio a bigger loop should work better but I would go with a single turn
large cross section of at least 50 feet.

Keep in mind what I wrote before that you could be living in a shielded
house and not know it if the exterior is stucco.

--
Telamon
Ventura, California