ELFA,

"BA" gave you some good advise.

Before you start the windings.

* Find a 6.5" to 8" Ferrite Rod Antenna (FRA).

* 10 Feet of Wire (Magnet or Litz)

* Cut a 2" X 2" piece of Typing/Copier Paper 20/24LB)

* Wrap the Copier Paper around the FRA
(About Two(2) Layers & Tape the Joint)
- - - The Copier Paper will 'form' a "Tube" that can be moved on the
FRA.

* Wrap 50-80 Wire Windings over the Copier Paper Tube to form a
"Moveable Coil Assembly (The Coil).

* Set the Windings at the very tip of one of the Ends of the FRA.

* Connect the Variable "Tuning" 360-400pf Capacitor (VTC) to the Leads
from the Windings.

# Place the FRA and VTC next to a Radio: Ideally you would use a
Radio with a Digital Frequncy Display and a "S" Meter.

* Starting-Mid-Point: "Tune" the Radio to a medium strength AM/MW
Radio Station at the Middle of the AM/MW Band 800-1000 kHz.
- Set the VTC to its Middle/Center Position.
- - Very Slowly 'move' The Coil from the Tip of the FRA towards the
center of the FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.
Note: If you 'find' a "Sweet Spot" on this first try: You have
Luck-Out !

* Top-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the High-End of the AM/MW Band 1500-1700 kHz.
- Set the VTC to its Fully "OPEN" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Starting-Mid-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

* Bottom-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the Low-End of the AM/MW Band 550-700 kHz.
- Set the VTC to its Fully "CLOSED" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Top-End-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

NOTE: Ideally these three points are within a 1/8" of each other and
you would set The Coil in the the middle of the three.

However the reality is that this will not be the case and you will
have to REMOVE/ADD a few Windings and try the above process again.

TIP: If you can "Tune" the Low-End and/or Middle of the AM/MW Band
then REMOVE a few Windings. Or, if you can "Tune" the High-End and/or
Middle of the AM/MW Band then ADD a few Windings.


iane ~ RHF
..
..
= = = "Brenda Ann"
= = = wrote in message ...
"elfa" wrote in message
...
I appreciate your offer of instructions re the ferrite bar antenna but I
think
I'll just skip it for now. This was the wrong group for this kind of
request.
It should have been in an electronics group.

elfa

The number of turns necessary for a loopstick antenna depends on several
factors.

1) the frequency range required
2) the permeability of the ferrite core
3) the spacing of the turns

For experimentation purposes, you might start with about 80 turns of AWG 30
enameled or cloth covered wire, contiguously spaced, near one end of the
core. With this, use a ~360 pF variable capacitor.

If you have a grid dip meter, you can easily find where this is resonant. If
you don't, then you have to poke about on the AM dial of a cheap radio, and
see where you can tune it.

RHF,

That post just made it into my "save" file. Thanks for the excellent
instruction.

-- Stinger
"RHF" wrote in message
om...
ELFA,

"BA" gave you some good advise.

Before you start the windings.

* Find a 6.5" to 8" Ferrite Rod Antenna (FRA).

* 10 Feet of Wire (Magnet or Litz)

* Cut a 2" X 2" piece of Typing/Copier Paper 20/24LB)

* Wrap the Copier Paper around the FRA
(About Two(2) Layers & Tape the Joint)
- - - The Copier Paper will 'form' a "Tube" that can be moved on the
FRA.

* Wrap 50-80 Wire Windings over the Copier Paper Tube to form a
"Moveable Coil Assembly (The Coil).

* Set the Windings at the very tip of one of the Ends of the FRA.

* Connect the Variable "Tuning" 360-400pf Capacitor (VTC) to the Leads
from the Windings.

# Place the FRA and VTC next to a Radio: Ideally you would use a
Radio with a Digital Frequncy Display and a "S" Meter.

* Starting-Mid-Point: "Tune" the Radio to a medium strength AM/MW
Radio Station at the Middle of the AM/MW Band 800-1000 kHz.
- Set the VTC to its Middle/Center Position.
- - Very Slowly 'move' The Coil from the Tip of the FRA towards the
center of the FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.
Note: If you 'find' a "Sweet Spot" on this first try: You have
Luck-Out !

* Top-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the High-End of the AM/MW Band 1500-1700 kHz.
- Set the VTC to its Fully "OPEN" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Starting-Mid-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

* Bottom-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the Low-End of the AM/MW Band 550-700 kHz.
- Set the VTC to its Fully "CLOSED" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Top-End-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

NOTE: Ideally these three points are within a 1/8" of each other and
you would set The Coil in the the middle of the three.

However the reality is that this will not be the case and you will
have to REMOVE/ADD a few Windings and try the above process again.

TIP: If you can "Tune" the Low-End and/or Middle of the AM/MW Band
then REMOVE a few Windings. Or, if you can "Tune" the High-End and/or
Middle of the AM/MW Band then ADD a few Windings.


iane ~ RHF
.
.
= = = "Brenda Ann"
= = = wrote in message ...
"elfa" wrote in message
...
I appreciate your offer of instructions re the ferrite bar antenna but
I
think
I'll just skip it for now. This was the wrong group for this kind of
request.
It should have been in an electronics group.

elfa

The number of turns necessary for a loopstick antenna depends on several
factors.

1) the frequency range required
2) the permeability of the ferrite core
3) the spacing of the turns

For experimentation purposes, you might start with about 80 turns of AWG
30
enameled or cloth covered wire, contiguously spaced, near one end of the
core. With this, use a ~360 pF variable capacitor.

If you have a grid dip meter, you can easily find where this is
resonant. If
you don't, then you have to poke about on the AM dial of a cheap radio,
and
see where you can tune it.

Stinger,

Thank You, ELFA did not indicate that he had any test equipment Grid
Dip Meter etc. So this was the simplest method by just using a basic
AM/MW Radio.

A Copy of this simple method is posted to:

* " Ferrite Rod Antenna for Experimenters" eGroup on YAHOO!
http://groups.yahoo.com/group/FerriteRodAntenna/

* "SWL Antennas and AM & FM Antennas" eGroup on YAHOO!
http://groups.yahoo.com/group/SWL-AM-FM-Antenna/


~ RHF
..
..
= = = "Stinger"
= = = wrote in message ...
RHF,

That post just made it into my "save" file. Thanks for the excellent
instruction.

-- Stinger
"RHF" wrote in message
om...
ELFA,

"BA" gave you some good advise.

Before you start the windings.

* Find a 6.5" to 8" Ferrite Rod Antenna (FRA).

* 10 Feet of Wire (Magnet or Litz)

* Cut a 2" X 2" piece of Typing/Copier Paper 20/24LB)

* Wrap the Copier Paper around the FRA
(About Two(2) Layers & Tape the Joint)
- - - The Copier Paper will 'form' a "Tube" that can be moved on the
FRA.

* Wrap 50-80 Wire Windings over the Copier Paper Tube to form a
"Moveable Coil Assembly (The Coil).

* Set the Windings at the very tip of one of the Ends of the FRA.

* Connect the Variable "Tuning" 360-400pf Capacitor (VTC) to the Leads
from the Windings.

# Place the FRA and VTC next to a Radio: Ideally you would use a
Radio with a Digital Frequncy Display and a "S" Meter.

* Starting-Mid-Point: "Tune" the Radio to a medium strength AM/MW
Radio Station at the Middle of the AM/MW Band 800-1000 kHz.
- Set the VTC to its Middle/Center Position.
- - Very Slowly 'move' The Coil from the Tip of the FRA towards the
center of the FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.
Note: If you 'find' a "Sweet Spot" on this first try: You have
Luck-Out !

* Top-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the High-End of the AM/MW Band 1500-1700 kHz.
- Set the VTC to its Fully "OPEN" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Starting-Mid-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

* Bottom-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the Low-End of the AM/MW Band 550-700 kHz.
- Set the VTC to its Fully "CLOSED" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Top-End-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

NOTE: Ideally these three points are within a 1/8" of each other and
you would set The Coil in the the middle of the three.

However the reality is that this will not be the case and you will
have to REMOVE/ADD a few Windings and try the above process again.

TIP: If you can "Tune" the Low-End and/or Middle of the AM/MW Band
then REMOVE a few Windings. Or, if you can "Tune" the High-End and/or
Middle of the AM/MW Band then ADD a few Windings.


iane ~ RHF
.
.
= = = "Brenda Ann"
= = = wrote in message ...
"elfa" wrote in message
...
I appreciate your offer of instructions re the ferrite bar antenna but
I
think
I'll just skip it for now. This was the wrong group for this kind of
request.
It should have been in an electronics group.

elfa

The number of turns necessary for a loopstick antenna depends on several
factors.

1) the frequency range required
2) the permeability of the ferrite core
3) the spacing of the turns

For experimentation purposes, you might start with about 80 turns of AWG
30
enameled or cloth covered wire, contiguously spaced, near one end of the
core. With this, use a ~360 pF variable capacitor.

If you have a grid dip meter, you can easily find where this is
resonant. If
you don't, then you have to poke about on the AM dial of a cheap radio,
and
see where you can tune it.

elfa, wrote:

All the devices that have been described by you draw the magnetic
component of the radio wave out of the air, and concentrate it in a core
that has a coil mounted on it. This induces RF voltage in the coil. In
most of these, that coil is connected to a variable capacitor. Both the
coil and the capacitor have a property called reactance, which resists the
flow of RF current. But the two components have reactances of opposite
signs (one positive, one negative), so when you adjust things so the
positive & negative numbers are equal at your frequency of interest, the
reactances cancel, and a large RF current flows. While this does bring in
one more control, the ability to 'peak' the coil to work best ay only one
frequency is usually worth it.

The trick to using this to boost reception is to have a coil that
intercepts more energy than your naked radio does. Ferrite has a high
permitivity (take my word for it), which causes the magnetic field that
would have flowed near the rod to go through it; the rod picks up energy
from a physical space larger than the rod.

Another approach is to build an air-core coil that encloses a lot of area.
This gives up compactness, but is well-suited to home construction with
balsa & plastic.

Unfortunately, another poster was right, unless you can give us some
quantative data about your rod & capacitor, we can't help with a
recommended turns count. To try a guess, start with 40 turns, tune
through your frequencies while tuning your loop's capacitor. When you
find a frequency where the capacitor can peak the signal (orthe noise),
adjust things: remove turns to move the loop's range to higher
frequencies, add to bring down.

Good luck.

--

R F Wieland Newark, DE 19711-5323 USA 39.68N 75.74W
Icom R75 Heathkit GR-81 Inverted-L in the attic
Reply to wieland at me dot udel dot edu

Iane:

- thanks for posting this, it is very helpful..

Dan


In article ,
(RHF) writes:

Subject: Homemade AM ferrite antenna question
From: (RHF)
Date: 20 Oct 2003 20:24:28 -0700

ELFA,

"BA" gave you some good advise.

Before you start the windings.

* Find a 6.5" to 8" Ferrite Rod Antenna (FRA).

* 10 Feet of Wire (Magnet or Litz)

* Cut a 2" X 2" piece of Typing/Copier Paper 20/24LB)

* Wrap the Copier Paper around the FRA
(About Two(2) Layers & Tape the Joint)
- - - The Copier Paper will 'form' a "Tube" that can be moved on the
FRA.

* Wrap 50-80 Wire Windings over the Copier Paper Tube to form a
"Moveable Coil Assembly (The Coil).

* Set the Windings at the very tip of one of the Ends of the FRA.

* Connect the Variable "Tuning" 360-400pf Capacitor (VTC) to the Leads
from the Windings.

# Place the FRA and VTC next to a Radio: Ideally you would use a
Radio with a Digital Frequncy Display and a "S" Meter.

* Starting-Mid-Point: "Tune" the Radio to a medium strength AM/MW
Radio Station at the Middle of the AM/MW Band 800-1000 kHz.
- Set the VTC to its Middle/Center Position.
- - Very Slowly 'move' The Coil from the Tip of the FRA towards the
center of the FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.
Note: If you 'find' a "Sweet Spot" on this first try: You have
Luck-Out !

* Top-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the High-End of the AM/MW Band 1500-1700 kHz.
- Set the VTC to its Fully "OPEN" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Starting-Mid-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

* Bottom-End-Point: "Tune" the Radio to a medium strength AM/MW Radio
Station at the Low-End of the AM/MW Band 550-700 kHz.
- Set the VTC to its Fully "CLOSED" Position.
- - Very Slowly 'move' The Coil from the 'prior' (Top-End-Point)
position towards the Tip of the FRA and then towards the center of the
FRA.
- - - Try to identify by Ear or Eye an change in the Quality and
Strength of Reception.
- - - - Mark-Measure-Record this 'position'.

NOTE: Ideally these three points are within a 1/8" of each other and
you would set The Coil in the the middle of the three.

However the reality is that this will not be the case and you will
have to REMOVE/ADD a few Windings and try the above process again.

TIP: If you can "Tune" the Low-End and/or Middle of the AM/MW Band
then REMOVE a few Windings. Or, if you can "Tune" the High-End and/or
Middle of the AM/MW Band then ADD a few Windings.


iane ~ RHF
.
.
= = = "Brenda Ann"
= = = wrote in message ...
"elfa" wrote in message
...
I appreciate your offer of instructions re the ferrite bar antenna but I
think
I'll just skip it for now. This was the wrong group for this kind of
request.
It should have been in an electronics group.

elfa

The number of turns necessary for a loopstick antenna depends on several
factors.

1) the frequency range required
2) the permeability of the ferrite core
3) the spacing of the turns

For experimentation purposes, you might start with about 80 turns of AWG 30
enameled or cloth covered wire, contiguously spaced, near one end of the
core. With this, use a ~360 pF variable capacitor.

If you have a grid dip meter, you can easily find where this is resonant.
If
you don't, then you have to poke about on the AM dial of a cheap radio, and
see where you can tune it.

You should look at:
http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html
(many simple schematics for buling crystal radios are also avaible over WWW pages)

elfa wrote:

I want to try to make a homemade ferrite antenna to improve the AM reception on
an old radio. I can't find any place on the internet that gives a simple
explanation of the how to's. All I want to know is how many winds of copper
wire and what lead connects to what radio connection. And also, just the most
basic of antenna principals involved.

Anyone have any suggestions?

thanks

elfa

Looked this over; utterly worthless without advanced math skills;

- Good for those what got em !



Subject: Homemade AM ferrite antenna question
From: Igor Gros
Date: 11/4/2003 3:05 AM Eastern Standard Time
Message-id:

You should look at:
http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html
(many simple schematics for buling crystal radios are also avaible over WWW
pages)

elfa wrote:

I want to try to make a homemade ferrite antenna to improve the AM
reception on
an old radio. I can't find any place on the internet that gives a simple
explanation of the how to's. All I want to know is how many winds of
copper
wire and what lead connects to what radio connection. And also, just the
most
basic of antenna principals involved.

Anyone have any suggestions?

thanks

elfa

Try 40 turns of wirewrap wire on the following ferrite:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=30573159 10

I measure 147uH which will put you in the center of the MW band with a 150
pF cap. This means that you can use the standard 10 - 356 pF variable cap.

Happy winding,

/Dave



"Soames123" wrote in message
...
Looked this over; utterly worthless without advanced math skills;

- Good for those what got em !



Subject: Homemade AM ferrite antenna question
From: Igor Gros
Date: 11/4/2003 3:05 AM Eastern Standard Time
Message-id:

You should look at:
http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html
(many simple schematics for buling crystal radios are also avaible over
WWW
pages)

elfa wrote:

I want to try to make a homemade ferrite antenna to improve the AM
reception on
an old radio. I can't find any place on the internet that gives a
simple
explanation of the how to's. All I want to know is how many winds of
copper
wire and what lead connects to what radio connection. And also, just
the
most
basic of antenna principals involved.

Anyone have any suggestions?

thanks

elfa

Try 40 turns of wirewrap wire on the following ferrite:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=30573159 10

I measure 147uH which will put you in the center of the MW band with a 150
pF cap. This means that you can use the standard 10 - 356 pF variable cap.

Happy winding,

/Dave



"Soames123" wrote in message
...
Looked this over; utterly worthless without advanced math skills;

- Good for those what got em !



Subject: Homemade AM ferrite antenna question
From: Igor Gros
Date: 11/4/2003 3:05 AM Eastern Standard Time
Message-id:

You should look at:
http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html
(many simple schematics for buling crystal radios are also avaible over
WWW
pages)

elfa wrote:

I want to try to make a homemade ferrite antenna to improve the AM
reception on
an old radio. I can't find any place on the internet that gives a
simple
explanation of the how to's. All I want to know is how many winds of
copper
wire and what lead connects to what radio connection. And also, just
the
most
basic of antenna principals involved.

Anyone have any suggestions?

thanks

elfa

Try 40 turns of wirewrap wire on the following ferrite:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=30573159 10

I measure 147uH which will put you in the center of the MW band with a 150
pF cap. This means that you can use the standard 10 - 356 pF variable cap.

Happy winding,

/Dave



"Soames123" wrote in message
...
Looked this over; utterly worthless without advanced math skills;

- Good for those what got em !



Subject: Homemade AM ferrite antenna question
From: Igor Gros
Date: 11/4/2003 3:05 AM Eastern Standard Time
Message-id:

You should look at:
http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html
(many simple schematics for buling crystal radios are also avaible over
WWW
pages)

elfa wrote:

I want to try to make a homemade ferrite antenna to improve the AM
reception on
an old radio. I can't find any place on the internet that gives a
simple
explanation of the how to's. All I want to know is how many winds of
copper
wire and what lead connects to what radio connection. And also, just
the
most
basic of antenna principals involved.

Anyone have any suggestions?

thanks

elfa