"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the
20 meter
band to 70 meter band area. I was looking for advice on what
materials to
use for the antenna and the lead in lines. I will hook it up to a
Drake r8B
radio. What is the minimum height it has to be? Where to ground
it?.
Actually, does it have to be grounded if the radio is grounded at
the
outlet?

I am a little limited in space as my yard is only 75 feet long and
there are
power lines at the front. I assume that they are the source of an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band or
range of frequencies. In fact, it performs well throughout the
shortwave
spectrum. See the following website for instructions on building a
good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but
when I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random
wires of different gauges?? John Doty's article mentioned
an 18 gauge wire hung more than a few feet above the
ground, but I'm just curious what sort of differences there
would be using, say, 14, 16 or 22 gauge wire in a similar
scenario. I can't imagine trying to test it without a load of
some sort.

--Mike L.

Michael Lawson wrote:

"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the
20 meter
band to 70 meter band area. I was looking for advice on what
materials to
use for the antenna and the lead in lines. I will hook it up to a
Drake r8B
radio. What is the minimum height it has to be? Where to ground
it?.
Actually, does it have to be grounded if the radio is grounded at
the
outlet?

I am a little limited in space as my yard is only 75 feet long and
there are
power lines at the front. I assume that they are the source of an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band or
range of frequencies. In fact, it performs well throughout the
shortwave
spectrum. See the following website for instructions on building a
good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but
when I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random
wires of different gauges?? John Doty's article mentioned
an 18 gauge wire hung more than a few feet above the
ground, but I'm just curious what sort of differences there
would be using, say, 14, 16 or 22 gauge wire in a similar
scenario. I can't imagine trying to test it without a load of
some sort.

Don't worry about it. The gauge of the wire will have an extremly minimal
effect, and besides, there are so many other variables as well.

dxAce
Michigan
USA

http://www.iserv.net/~n8kdv/dxpage.htm

In article ,
"Michael Lawson" wrote:

"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the
20 meter band to 70 meter band area. I was looking for advice on
what materials to use for the antenna and the lead in lines. I
will hook it up to a Drake r8B radio. What is the minimum height
it has to be? Where to groundit?.

Actually, does it have to be grounded if the radio is grounded at
the outlet?

I am a little limited in space as my yard is only 75 feet long
and there are power lines at the front. I assume that they are
the source of an irritating hum on the receiver on certain
frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking
of building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band
or range of frequencies. In fact, it performs well throughout the
shortwave spectrum. See the following website for instructions on
building a good low noise inverted-L antenna. I use this kind with
my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but when
I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random wires of
different gauges?? John Doty's article mentioned an 18 gauge wire
hung more than a few feet above the ground, but I'm just curious what
sort of differences there would be using, say, 14, 16 or 22 gauge
wire in a similar scenario. I can't imagine trying to test it
without a load of some sort.

A decrease in the gauge number means an increase in the wire diameter.
If you increase the wire diameter the impedance goes down. If you place
the wire closer to the ground the impedance goes down.

The difference between a step in wire gauge is about 12 ohms.

A 16 gauge wire 5 to 15 feet off the ground ranges from 500 to 600
ohms.

--
Telamon
Ventura, California

Michael Lawson wrote:

"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in the
20 meter
band to 70 meter band area. I was looking for advice on what
materials to
use for the antenna and the lead in lines. I will hook it up to a
Drake r8B
radio. What is the minimum height it has to be? Where to ground
it?.
Actually, does it have to be grounded if the radio is grounded at
the
outlet?

I am a little limited in space as my yard is only 75 feet long and
there are
power lines at the front. I assume that they are the source of an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific band or
range of frequencies. In fact, it performs well throughout the
shortwave
spectrum. See the following website for instructions on building a
good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but
when I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random
wires of different gauges?? John Doty's article mentioned
an 18 gauge wire hung more than a few feet above the
ground, but I'm just curious what sort of differences there
would be using, say, 14, 16 or 22 gauge wire in a similar
scenario. I can't imagine trying to test it without a load of
some sort.

--Mike L.

The size (gauge) of the wire is not important for a *reception* antenna.
It does matter for a transmitting antenna. The typical inverted-L has an
impedance of several hundred ohms for much of it's frequency range.
That's why a 9:1 (impedance) balun is often used. If the receiver has an
antenna input impedance of about 50-ohms, a 9:1 balun will match it to a
450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is
actually 3:1. My balun has a primary winding with 10-turns and a
secondary with 30-turns. I used #22 enameled wire on a 1/2" dia. type-43
ferrite core. I plan to make a new balun using a 'binocular' core. This
core shape makes the balun's impedance more consistent throughout it's
frequency range.


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"starman" wrote in message
...
Michael Lawson wrote:

"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in
the
20 meter
band to 70 meter band area. I was looking for advice on what
materials to
use for the antenna and the lead in lines. I will hook it up
to a
Drake r8B
radio. What is the minimum height it has to be? Where to
ground
it?.
Actually, does it have to be grounded if the radio is grounded
at
the
outlet?

I am a little limited in space as my yard is only 75 feet long
and
there are
power lines at the front. I assume that they are the source of
an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are
thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific
band or
range of frequencies. In fact, it performs well throughout the
shortwave
spectrum. See the following website for instructions on building
a
good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but
when I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random
wires of different gauges?? John Doty's article mentioned
an 18 gauge wire hung more than a few feet above the
ground, but I'm just curious what sort of differences there
would be using, say, 14, 16 or 22 gauge wire in a similar
scenario. I can't imagine trying to test it without a load of
some sort.

--Mike L.

The size (gauge) of the wire is not important for a *reception*
antenna.
It does matter for a transmitting antenna. The typical inverted-L
has an
impedance of several hundred ohms for much of it's frequency range.
That's why a 9:1 (impedance) balun is often used. If the receiver
has an
antenna input impedance of about 50-ohms, a 9:1 balun will match it
to a
450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is
actually 3:1. My balun has a primary winding with 10-turns and a
secondary with 30-turns. I used #22 enameled wire on a 1/2" dia.
type-43
ferrite core. I plan to make a new balun using a 'binocular' core.
This
core shape makes the balun's impedance more consistent throughout
it's
frequency range.

Is there much of a difference in the gauge of the enameled
wire wound around the core?? I followed John Bryant's
lead in his article and used 30 gauge wire, but I was thinking
that 26 would be easier to handle.

--Mike L.

Michael Lawson wrote:

"starman" wrote in message
...
Michael Lawson wrote:

"starman" wrote in message
...
Pierre Vachon wrote:

Hi there, I am trying to build a longwire antenna for use in
the
20 meter
band to 70 meter band area. I was looking for advice on what
materials to
use for the antenna and the lead in lines. I will hook it up
to a
Drake r8B
radio. What is the minimum height it has to be? Where to
ground
it?.
Actually, does it have to be grounded if the radio is grounded
at
the
outlet?

I am a little limited in space as my yard is only 75 feet long
and
there are
power lines at the front. I assume that they are the source of
an
irritating
hum on the receiver on certain frequencies.

Thanks for the help in advance.

Pierre

A real longwire antenna is much longer than what you are
thinking of
building. The antenna you describe is called a 'random wire' or
inverted-L. This kind of antenna is not tuned for a specific
band or
range of frequencies. In fact, it performs well throughout the
shortwave
spectrum. See the following website for instructions on building
a
good
low noise inverted-L antenna. I use this kind with my R8B.

http://www.anarc.org/naswa/badx/ante...e_antenna.html

Hmm. That brings up a question that I'd thought of earlier, but
when I was writing my posts, I forgot to put it in.

How do you figure out the impedance of various random
wires of different gauges?? John Doty's article mentioned
an 18 gauge wire hung more than a few feet above the
ground, but I'm just curious what sort of differences there
would be using, say, 14, 16 or 22 gauge wire in a similar
scenario. I can't imagine trying to test it without a load of
some sort.

--Mike L.

The size (gauge) of the wire is not important for a *reception*
antenna.
It does matter for a transmitting antenna. The typical inverted-L
has an
impedance of several hundred ohms for much of it's frequency range.
That's why a 9:1 (impedance) balun is often used. If the receiver
has an
antenna input impedance of about 50-ohms, a 9:1 balun will match it
to a
450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is
actually 3:1. My balun has a primary winding with 10-turns and a
secondary with 30-turns. I used #22 enameled wire on a 1/2" dia.
type-43
ferrite core. I plan to make a new balun using a 'binocular' core.
This
core shape makes the balun's impedance more consistent throughout
it's
frequency range.

Is there much of a difference in the gauge of the enameled
wire wound around the core?? I followed John Bryant's
lead in his article and used 30 gauge wire, but I was thinking
that 26 would be easier to handle.

26 will work just fine. I've typically used 22.

dxAce
Michigan
USA

http://www.iserv.net/~n8kdv/dxpage.htm

Michael Lawson wrote:

"starman" wrote in message

The size (gauge) of the wire is not important for a *reception*
antenna.
It does matter for a transmitting antenna. The typical inverted-L
has an
impedance of several hundred ohms for much of it's frequency range.
That's why a 9:1 (impedance) balun is often used. If the receiver
has an
antenna input impedance of about 50-ohms, a 9:1 balun will match it
to a
450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is
actually 3:1. My balun has a primary winding with 10-turns and a
secondary with 30-turns. I used #22 enameled wire on a 1/2" dia.
type-43
ferrite core. I plan to make a new balun using a 'binocular' core.
This
core shape makes the balun's impedance more consistent throughout
it's
frequency range.

Is there much of a difference in the gauge of the enameled
wire wound around the core?? I followed John Bryant's
lead in his article and used 30 gauge wire, but I was thinking
that 26 would be easier to handle.

--Mike L.

Use whatever size wire works best on the ferrite core you have.


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= = = starman wrote in message
= = = ...
Michael Lawson wrote:

"starman" wrote in message

The size (gauge) of the wire is not important for a *reception*
antenna.
It does matter for a transmitting antenna. The typical inverted-L
has an
impedance of several hundred ohms for much of it's frequency range.
That's why a 9:1 (impedance) balun is often used. If the receiver
has an
antenna input impedance of about 50-ohms, a 9:1 balun will match it
to a
450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is
actually 3:1. My balun has a primary winding with 10-turns and a
secondary with 30-turns. I used #22 enameled wire on a 1/2" dia.
type-43
ferrite core. I plan to make a new balun using a 'binocular' core.
This
core shape makes the balun's impedance more consistent throughout
it's
frequency range.

Is there much of a difference in the gauge of the enameled
wire wound around the core?? I followed John Bryant's
lead in his article and used 30 gauge wire, but I was thinking
that 26 would be easier to handle.

--Mike L.

Use whatever size wire works best on the ferrite core you have.


STARMAN,

Isn't Type 43 the recommended as a Balun "Core Material" ?

Why isn't Type 61 also a 'suggested' Balun Core Material ?

NOTE: Matching Transformer = Balun = UnUn

True Story: A while back I bought a Grab Bag of Feritte Cores on eBay.
Some of them had a #20 Enameled Wire wrapped on them with 36 Turns.
They were about 1" OD x 1/2" ID x 1/2" H. So I thought, why not
try them as an Matching Transformer on an 'old' Telephone Two Wire
Service Line (pre-1950s) that runs overhead about 75 Ft from
the Power Pole to the House. Being lazy I simply wrapped a Twelve
Turn (12T) Secondary and wired it up with a #22 Magnet Wire from a
RadioShack 'three pack' Catalog # 278-1345 ($5). Well 36:12 Turns
worked good for AM/MW and up to 7 MHz but the Signal Levels fell
off after 7 MHz. So then I tried Reducing the Primary to 30
Turns and the Secondary to 10 Turns. Again the AM/MW Band was
good and the Shortwave coverage went up to 23 MHz. Not being
one to settle for 'good enough'; I then tried Reducing the Primary
to 24 Turns and the Secondary to 8 Turns. Well the AM/MW Reception
went down and the Shortwave Bands reception picked up to the CB Band.
So it seems that the 'majic' 30 Turns and 10 Turns worked the best
for my needs using this ?Core?.

TESTING: The receiver for this Test was an Icom IC-R75.
http://www.icomamerica.com/products/receivers/r75/
My Matching Transformer "Test Standard" was an ICE 180A.
http://www.arraysolutions.com/Produc...age%20Matching
My Test Measurement were with "My Ears" and 'My Eyes' (S-Meter).
The 'old' Telephone Service Line was a Two Wire (Copper Clad
Steel?) Cable. One Wire was used for the ICE 180A and the
other Wire was used for the ?Core? Matching Transformer.

FWIW: Reading your statement about the Binocular Cores, I
have just ordered some from Universal-Radio.Com to Test.
It is my understanding that One Turn 'counts' for Two when
You use a Binocular Core. Now Is That True ?

Also, I have a SWL 10:1 Balun that is made by "RF Junkie"
and will be testing it soon using the same test-set-up.
* Two Shortwave Listener (SWL) 10:1 Baluns for Random Wire Antennas
http://groups.yahoo.com/group/Shortw...a/message/1523


iane ~ RHF
..
..

(RHF) wrote in message m...

Good information snipped

STARMAN,

Isn't Type 43 the recommended as a Balun "Core Material" ?

Why isn't Type 61 also a 'suggested' Balun Core Material ?

NOTE: Matching Transformer = Balun = UnUn

True Story: A while back I bought a Grab Bag of Feritte Cores on eBay.
Some of them had a #20 Enameled Wire wrapped on them with 36 Turns.
They were about 1" OD x 1/2" ID x 1/2" H. So I thought, why not
try them as an Matching Transformer on an 'old' Telephone Two Wire
Service Line (pre-1950s) that runs overhead about 75 Ft from
the Power Pole to the House. Being lazy I simply wrapped a Twelve
Turn (12T) Secondary and wired it up with a #22 Magnet Wire from a
RadioShack 'three pack' Catalog # 278-1345 ($5). Well 36:12 Turns
worked good for AM/MW and up to 7 MHz but the Signal Levels fell
off after 7 MHz. So then I tried Reducing the Primary to 30
Turns and the Secondary to 10 Turns. Again the AM/MW Band was
good and the Shortwave coverage went up to 23 MHz. Not being
one to settle for 'good enough'; I then tried Reducing the Primary
to 24 Turns and the Secondary to 8 Turns. Well the AM/MW Reception
went down and the Shortwave Bands reception picked up to the CB Band.
So it seems that the 'majic' 30 Turns and 10 Turns worked the best
for my needs using this ?Core?.

RHF - it sounds like you did not know what the material for this core
was (43 vs. 61 or other) - right? Is it possible that the frequency
range is more dependent on the number of turns (inductance?) than the
actual material? This is not a trick question...

TESTING: The receiver for this Test was an Icom IC-R75.
http://www.icomamerica.com/products/receivers/r75/
My Matching Transformer "Test Standard" was an ICE 180A.
http://www.arraysolutions.com/Produc...age%20Matching
My Test Measurement were with "My Ears" and 'My Eyes' (S-Meter).
The 'old' Telephone Service Line was a Two Wire (Copper Clad
Steel?) Cable. One Wire was used for the ICE 180A and the
other Wire was used for the ?Core? Matching Transformer.

Question - what is the advantage of using the ICE 180A (1.5-30 MHz)
over the 180C (0.1 - 30 MHz)? Is the 180A inherently better suited to
SW because it does not need to be so broadbanded? Or will the other
work as well, PLUS get you MW? Do these use binocular cores? Or just
one of them?

FWIW: Reading your statement about the Binocular Cores, I
have just ordered some from Universal-Radio.Com to Test.
It is my understanding that One Turn 'counts' for Two when
You use a Binocular Core. Now Is That True ?

I would love to know this also, and also see a GOOD diagram of how to
wire a binocular core.

Also, I have a SWL 10:1 Balun that is made by "RF Junkie"
and will be testing it soon using the same test-set-up.
* Two Shortwave Listener (SWL) 10:1 Baluns for Random Wire Antennas
http://groups.yahoo.com/group/Shortw...a/message/1523

It is great to see all these fine antenna posts - becoming familiar
with the experience of others, and ultimately (hopefully) contributing
something that may help others, is the best and highest use of this
medium, I think (oh, yeah, that and name-calling over politics ;-)

Bruce Jensen

Isn't Type 43 the recommended as a Balun "Core Material" ?

Type 43 is optimal for the shortwave (HF) spectrum.

Why isn't Type 61 also a 'suggested' Balun Core Material ?

The 'Q' of type-61 makes it too selective for HF. You want the balun to
be broadband not peaked for a particular frequency.

Is it possible that the frequency
range is more dependent on the number of turns (inductance?) than the
actual material? This is not a trick question...

The ferrite composition plays a large role in determining the effective
frequency range of the coil. In the case of a balun/unun you're not
trying to make a tuned coil. You want it to be efficient over the
desired frequency range. See the following webpage for ferrite core
info':

http://www.universal-radio.com/catal.../amidonT1.html

FWIW: Reading your statement about the Binocular Cores, I
have just ordered some from Universal-Radio.Com to Test.
It is my understanding that One Turn 'counts' for Two when
You use a Binocular Core. Now Is That True ?

I would love to know this also, and also see a GOOD diagram of how to
wire a binocular core.

Here's how to wind ferrite cores, including binocular ones:

http://www.oselectronics.com/downloa...ansformers.pdf


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