In article . com,
"RHF" wrote:
Telamon wrote:
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...ry=about_conta
ct
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.
-R- That is what I initially thought - but then may be it is.
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.
-R- Yes I am using a 3/32" Plug with the Tip-and-Ring not the Barrel
for the AM/MW Loop Antenna.
You only describe things as no success and that is not very
descriptive.
-R- That is true.
Do you not get any signal with the loop than comes with the radio?
-R- I get AM/MW Radio Signals - But not much stronger then using
the (OEM) smaller Loop Antenna located In-Doors and Not Across
the AM/MW Band. - - - This is why I was wondering if this Loop
Antenna was designed to be a Circuit Element in a Tuned RF Stage
within the Radio.
-Note- My first Loop Antenna for this Radio was located 'out-side' and
was simply 20 Turns on a 24" Square Frame with a 20 Foot Coax
Cable and performed poorer then the small (OEM) Loop Antenna.
[ Basically a Larger Un-Tuned Loop Antenna located Out-Side. ]
-Next- I started reducing the Number of Turns in this Loop Antenna
by Twos : 20 Turns 18 Turns 16 Turns 14 Turns 12 Turns
10 Turns 8 Turns 6 Turns 4 Turns 2 Turns - Again with
poor results.
-Then- Went back to the Drawing Boad and Calculated that
the small (OEM) Loop Antenna was about 17.3 uH.
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
? Question - Can anyone confirm this 'uH' Number ?
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.
Again - 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 small (OEM) Loop Antenna.
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?
-R- The Large Loop is only slightly better on a Few AM/MW
Radio Stations and does not cover the complete AM/MW
Broadcast Band.
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.
-R- This is bigger then the View {The Viewer} from the Kitchen
will allow.
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.
-R- Six-Inch Walls with Insulation (No Foil) and Sheet Rock
and Wood interior Wall surfaces with "HardiPlank" Filber
Cement Siding made from Portland Cement Mixed with
Ground Sand, Cellulose fiber, and other Additives. {No Iron
or Steel}
Telamon,
I have used the Select-A-Tenna with the Cambridge SoundWorks
# 740 Radio using a 1/8" Mono-Plug into the Select-A-Tenna and
a 3/32" Stereo Plug {Tip-and-Ring - not the Barrel} into the Radio.
While this works OK - each time the AM Radio Station is changed
the Antenna must be re-tuned. One of the Users of this Radio in
the Kitchen does not want to deal with Playing-wth-the-Antenna.
Also - I have used the Crane AM/MW Twin Coil Ferrite Rod Antenna
and the TG33 In-Door AM/BCB Medium Wave Active Loop Antenna
with the Cambridge SoundWorks # 740 Radio both of which tend
to OverLoad the Radio's RF Front-End. Plus again they need the
External AM/MW Antenna Re-Tuned each time that the Radio
Stations is changed.
Currently - I can use the small little (OEM) Loop Antenna with the
Select-A-Tenna {Taped to the Inside Top of the Select-A-Tenna}
and this will help to improve the AM/MW Radio Reception, some
what . . .
I want to simply have an "Un-Tuned" Large External AM/MW
Loop Antenna that is located 'out-side' that does not requirer
Tuning and gives me improved AM/MW Radio reception. ~ RHF
A large loop does not need to be tuned.
Start with the 50 foot circumference loop connected to the radio from
the antenna. If that does not overload the radio front end then try 75
or 100 foot. You can tack one up for starters to see how it works with
that radio and when you find a size that works well then you can make
the effort to make it more robust against the elements.
According to the spec you should use the stereo jack, ring and tip. The
center of the coax should probably go to the tip. Try it both ways to
see which set of connections has the least noise.
--
Telamon
Ventura, California