Simple AM Loop Antenna?
 

Bill ha escrito:

Hello everyone :) I am looking for detailed plans for an AM loop. I will
be using it only for one frequency 1370AM so I dont want any tuners just a
simple AM Loop antenna for my AM radio. I will have to solder a 1/8 plug to
a 6-8 ft feedline to connect to my radio. It is a Kaito portable model
1103. I want to built this AM Loop cause I listen to talk radio alot and
the static and other distant stations sometimes make it hard. I have done
alot of looking around on google searches but have found no real detailed
plans I am not sure if I should go with edge wound or Spiral wound. Any
info you guys can give especially a detailed plan would be greatly
appreciated. or maybe there is a website I may not have seen you would like
to suggest. I am sure I have seen most of them atleast the most popular
ones. Anyways thanks in advance for any input:) Bill

Hello Bill,

Regarding your AM loop antenna.

Are you sure the external antenna socket also works for AM? You may
check this by inserting a plug without antenna. The ferrite antenna in
your radio will not be that bad.

You mentioned static and other distant stations. I am not sure whether
the loop will improve the reception. Has the signal from your favorite
radio station sufficient strength (on your current radio)?

Before you build, try to locate (with your current receiver) the best
place and orientation for your loop to be built. Do not use the
external adapter for this. If you cannot find a place/orientation with
good reception, a loop will not do much better.

If you found a good place, power your radio via the mains adapter. This
will clarify whether noise from the mains enters the ferrite antenna.
If so, the loop design must be such that noise does not reach the loop
via the cable between the loop and your receiver.

Generaly a loop will only help to overcome the radio's internal noise
(bad Sensitivity) and spurious products (generated by your receiver)
and interference from nearby sources (electronic equipment). The last
item only, when you can position your loop away from any interfering
source.

The loop will also not improve interference from a very strong adjacent
station. You may orient the loop to get a strong adjacent station into
a null, but this is possible with the built-in ferrite antenna too.

Regarding tuning.
With average means, a resonating (=tuned) loop can be made smaller and
better. When you use fixed capacitors for most of the required
capacitance, you may use a smaller (mica compression) trimmer capacitor
to do the fine tuning to your desired frequency.

I hope this will help you a bit.

Best regards,

Wim
PA3DJS

Simple AM Loop Antenna?
 

Bill wrote:
Yes I have lol :) The station I am trying to recieve usually comes in pretty
good but sometimes at night it gets noisy. It is my understanding that an
external AM Loop antenna will recieve better than an internal loop that
comes with a small portable. I also have heard that a Loop picks up less
noise than an internal ferrite loop or random wire would. I have heard that
these external AM Loop antennas used to be quite common in the good ol'
days. But that they fell out of favor with most people to be replaced with
the internal ferrite loopstick antennas. If anyone has some detailed plans
for these older styled external AM Loop antennas I would really like to get
ahold of them. Thanks in Advance :) Bill

A friend of mine makes them. He uses the variable capacitor
out of old AM radios. He winds a number of turns of #30 wire
on a one foot diameter round piece of Styrofoam. He first
determined the number of turns needed by GDOing the coil
and cap in parallel to about 550 kc. Seems to me he used
20-30 turns. Just sitting it close to the radio and tuning
it to resonance solved his reception problem. It was resonant
and directional and its field was all the internal ferrite
loop antenna needed in his case. CCrane sells similar loops
under the trade name Select-A-Tenna.

http://www.ccrane.com/antennas/am-antennas/
--
73, Cecil http://www.w5dxp.com

Simple AM Loop Antenna?
 

Bill wrote:
Hello everyone :) I am looking for detailed plans for an AM loop. I will
be using it only for one frequency 1370AM so I dont want any tuners just a
simple AM Loop antenna for my AM radio. I will have to solder a 1/8 plug to
a 6-8 ft feedline to connect to my radio. It is a Kaito portable model
1103. I want to built this AM Loop cause I listen to talk radio alot and
the static and other distant stations sometimes make it hard. I have done
alot of looking around on google searches but have found no real detailed
plans I am not sure if I should go with edge wound or Spiral wound. Any
info you guys can give especially a detailed plan would be greatly
appreciated. or maybe there is a website I may not have seen you would like
to suggest. I am sure I have seen most of them atleast the most popular
ones. Anyways thanks in advance for any input:) Bill
Bill,
I have built a number of small receiving loops, and they all work very
well. The easiest way to design the loop is to use a small (and free)
program written by Reg Edwards. Go to his website
(http://www.btinternet.com/~g4fgq.reg...3.html#S301%22) and download
RJELOOP3. It will give you all the info you need, including the
approximate capacitance to resonate the loop. The basic loop consists of
about .1 wavelength of wire for the highest frequency of interest. A
larger loop with fewer turns is much more efficient than a smaller one
using more turns. You will need a variable cap to determine resonance -
the thing tunes too sharp to "cut and try". Once the cap value is
determined, have it measured and make up a fixed cap if you really don't
want to use a variable. You can use a single turn of wire around the
main loop as a low Z pickup that won't excessively load the main loop,
of come off the cap directly to a hi Z FET amp with a low Z output to
the radio. That makes tuning really sharp. These loops have very sharp
rejection, but work best during the day. At night, there are often too
many interferring stations, but it's still worth a try.

bob baldwin

Simple AM Loop Antenna?
 

Bill wrote:
Hello everyone :) I am looking for detailed plans for an AM loop. I will
be using it only for one frequency 1370AM so I dont want any tuners just a
simple AM Loop antenna for my AM radio. I will have to solder a 1/8 plug to
a 6-8 ft feedline to connect to my radio. It is a Kaito portable model
1103. I want to built this AM Loop cause I listen to talk radio alot and
the static and other distant stations sometimes make it hard. I have done
alot of looking around on google searches but have found no real detailed
plans I am not sure if I should go with edge wound or Spiral wound. Any
info you guys can give especially a detailed plan would be greatly
appreciated. or maybe there is a website I may not have seen you would like
to suggest. I am sure I have seen most of them atleast the most popular
ones. Anyways thanks in advance for any input:) Bill

Bill,

Forget about the antenna problem. The bigger challenge is distinguishing
talk radio programming from static and interference, even if the radio
reception is perfect.

8-)

73,
Gene
W4SZ

Simple AM Loop Antenna?
 

Allodoxaphobia wrote:
On Tue, 5 Dec 2006 20:34:30 -0600, Bill wrote:
Thanks for the input Christopher :) I am indeed determined to build one.
I don't want to build a tuning one though.

Go ahead and build a tuneable one. It's not _that_ more complicated.
Besides, the minute you would finish your no-tune antenna, Clear Channel
Communications will buy up your favorite talk station and convert it to
country and western. Then you'll have to look elsewhere up and down the
AM band.

Jonesy


I thought Colorado was part of the Wild West. Is is legal to listen to
anything other than C&W?

8-)

73,
Gene
W4SZ

Simple AM Loop Antenna?
 

"Bill" wrote in message
. ..
Hello everyone :) I am looking for detailed plans for an AM loop. I will
be using it only for one frequency 1370AM so I dont want any tuners just a
simple AM Loop antenna for my AM radio. I will have to solder a 1/8 plug
to
a 6-8 ft feedline to connect to my radio. It is a Kaito portable model
1103. I want to built this AM Loop cause I listen to talk radio alot and
the static and other distant stations sometimes make it hard. I have done
alot of looking around on google searches but have found no real detailed
plans I am not sure if I should go with edge wound or Spiral wound. Any
info you guys can give especially a detailed plan would be greatly
appreciated. or maybe there is a website I may not have seen you would
like
to suggest. I am sure I have seen most of them atleast the most popular
ones. Anyways thanks in advance for any input:) Bill

Bill,
Make your loop tunable. Variable caps aren't that hard to find.
Find a program to calculate the inductance of an inductor.
Try a google search of Reg Edwards, Reg is no longer with us but
his wonderful programs are still available.
(Someone else may want to post some solenoid inductance calculators)
Make an inductor of 240uh. ( Yes, other values will work)
A pure 240uh inductor and a 56pf cap resonate at about 1370khz.
(no inductor is pure, your inductor will have interwinding capacitance,
maybe 15pf, so 56pf minus 15pf is 41pf) So 41pf would make it resonate
at 1370khz. (pf = picofarad)
You could use a 100pf cap that will tune from about 1000khz to almost
1600khz.
Using a 365pf cap, this will tune almost the entire AM band.

Make an inductor of whatever size you are comfortable with 1ft to 8ft.
(Rotation is important but once you find the direction that minimizes noise
for your one station you have it.) So if you have a wall that is oriented
correctly
you could string wire around the corners.
You can go simple, as in wind it on styrofoam or a carboard box or spend
time
on a good frame and base and easy rotation.
If you get this far then there are a few ways to couple the signal into
your radio.
Tell me what you don't understand and I'll do my best to inform you.
Mike

Simple AM Loop Antenna?
 

Gene Fuller wrote:
Bill wrote:
Hello everyone :) I am looking for detailed plans for an AM loop. I
will be using it only for one frequency 1370AM so I dont want any
tuners just a simple AM Loop antenna for my AM radio. I will have to
solder a 1/8 plug to a 6-8 ft feedline to connect to my radio. It is a
Kaito portable model 1103. I want to built this AM Loop cause I listen
to talk radio alot and the static and other distant stations sometimes
make it hard. I have done alot of looking around on google searches
but have found no real detailed plans I am not sure if I should go
with edge wound or Spiral wound. Any info you guys can give especially
a detailed plan would be greatly appreciated. or maybe there is a
website I may not have seen you would like to suggest. I am sure I
have seen most of them atleast the most popular ones. Anyways thanks
in advance for any input:) Bill

Bill,

Forget about the antenna problem. The bigger challenge is distinguishing
talk radio programming from static and interference, even if the radio
reception is perfect.

8-)

73,
Gene
W4SZ

Personally, I love talk radio. I have, long ago, given up on getting
any real information from major networks ... but then if I had to
listen to rush, or chaps like him, I'd abandon talk radio also!

A tuned loop is the way to go. The only real practical application of
one needs a variable cap in my humble opinion ...

JS

Simple AM Loop Antenna? may have found it
 

On Wed, 6 Dec 2006 00:07:24 -0600, "Bill" wrote:

After searching for about a week now on Google I think I may have stumbled
on something here. What do you guys think about this AM loop? If nothing
else it should atleast work better than the internal Ferrite Loopstick
right? It requires no tuner.
http://members.cox.net/rwagoner/columns/am_antenna.html

Hi Bill,

Give it a try. It may work for what you want it to do, but if you add
a capacitor, it will do considerably better. Also, claims of
canceling noise are rarely demonstrated without care and attention to
design (this one does not go that extra mile).

73's
Richard Clark, KB7QHC

Simple AM Loop Antenna?
 

Bill wrote:
...

Far as mw loops go, this person has put together a reasonable page with
good links:


http://www.mindspring.com/~loop_antenna/

JS

Simple AM Loop Antenna?
 

Gene Fuller wrote:
Is is legal to listen to anything other than C&W?

Johnny Cash was doing rap long before there were
any rappers. :-)
--
73, Cecil http://www.w5dxp.com