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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(RHF) wrote in message om...
= = = "Pierre Vachon" wrote in message
= = = ...

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?


A year or so ago I had to come up with a replacement for an ageing
vertical antenna for my amateur radio station...After researching, I
decided to put up a full wave loop cut for 80 meters..Im going to
quote some sentences from this article, which you should check out:

http://www.bloomington.in.us/~wh2t/loop.html

"To determine the approximate length in feet of a Full Wave Loop
antenna use the formula 1005/Freq in Mhz = length in feet. For 160
meters a full wave loop antenna resonant at 1.9 Mhz would be about 529
feet long.

For the 75 meter band a full wave loop antenna resonant at 3.85 would
be about 261 feet long. A full wave for 3.9 Mhz = 257 Feet 8 inches. "

I happened to design mine for the 75/80 meter band.

"This type of antenna doesn't depend on an efficient ground system for
efficient performance. The impedance of a Full Wave Loop antenna is
theoretically in the vicinity of 100 ohms.

Connect one end of the wire to the coax center and Connect the coax
shield to the other end of the wire. Be sure and seal the end of the
coax against water. Form the wire in a loop and run it horizontally to
trees or whatever supports are handy. Be sure to insulate the wire
from the supports. "

Now, this antenna works great on receive and transmit on everything
from 75/80 meters and up (10-80) for transmit, the meager automatic
antenna tunner in me bloody kenwood ts450sat tunes it..amazing..and
the one band that sometimes gives me a bit of trouble is 15 meters,
where I have to use the external tuner..

And it hears really good everywhere my radio will go (general
coverage)...mine is only up an average of about 20 ft..

So, if you have the room I'd seriously consider a full wave loop..good
luck..

Steve
kb8viv

"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

= = = (Steve) wrote in message
= = = . com...
(RHF) wrote in message om...
= = = "Pierre Vachon" wrote in message
= = = ...

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?


A year or so ago I had to come up with a replacement for an ageing
vertical antenna for my amateur radio station...After researching, I
decided to put up a full wave loop cut for 80 meters..Im going to
quote some sentences from this article, which you should check out:

http://www.bloomington.in.us/~wh2t/loop.html

"To determine the approximate length in feet of a Full Wave Loop
antenna use the formula 1005/Freq in Mhz = length in feet. For 160
meters a full wave loop antenna resonant at 1.9 Mhz would be about 529
feet long.

For the 75 meter band a full wave loop antenna resonant at 3.85 would
be about 261 feet long. A full wave for 3.9 Mhz = 257 Feet 8 inches. "

I happened to design mine for the 75/80 meter band.

"This type of antenna doesn't depend on an efficient ground system for
efficient performance. The impedance of a Full Wave Loop antenna is
theoretically in the vicinity of 100 ohms.

Connect one end of the wire to the coax center and Connect the coax
shield to the other end of the wire. Be sure and seal the end of the
coax against water. Form the wire in a loop and run it horizontally to
trees or whatever supports are handy. Be sure to insulate the wire
from the supports. "

Now, this antenna works great on receive and transmit on everything
from 75/80 meters and up (10-80) for transmit, the meager automatic
antenna tunner in me bloody kenwood ts450sat tunes it..amazing..and
the one band that sometimes gives me a bit of trouble is 15 meters,
where I have to use the external tuner..

And it hears really good everywhere my radio will go (general
coverage)...mine is only up an average of about 20 ft..

So, if you have the room I'd seriously consider a full wave loop..good
luck..

Steve
kb8viv

STEVE,

Check-Out the "SkyWire Loop Antennas" eGroup on YAHOO !
http://groups.yahoo.com/group/SkyWires/

Dr. Ace [WH2T] is one of the Moderators of the eGroup.
http://www.bloomington.in.us/~wh2t/loop.html

A Critical requirement for a SkyWire Loop Antenna is "LAND" & Space.

SkyWire Loop Antenna Size per Square Side:
160 Meter Band = 529 Feet Loop = 132 Feet Side = "SPACE"
80 Meter Band = 268 Feet Loop = 67 Feet Side = 'Space'
40 Meter Band = 141 Feet Loop = 35 Feet Side = space
20 Meter Band = 71 Feet Loop = 18 Feet Side
10 Meter Band = 35 Feet Loop = 9 Feet Side

give me land lots of land to build antennas on, don't CCR me in ~ RHF
..

Hi RHF, I used to subscribe to it but I tend to change hobbies in the Summer
LOL..Anyway, last year I remember we were trying to have a net (so to speak) on
hf and it never really materialized. When summer hit I was back into my other
hobby of motorcycles..I should resubscribe though, if I remember correctly
there was a pretty good group there..Thanks again for the invite..

Steve
kb8viv

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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---= East/West-Coast Server Farms - Total Privacy via Encryption =---

= = = 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

In article ,
(bpnjensen) wrote:

(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...

Well, actually in a way it is a trick question. Inductors and
transformers are complex devices. Small differences in construction
will have a large effect on performance. How you connect it will change
its performance. Where (in frequency) you make measurement will affect
the results. I mention this because you want it to work from .5 MHz to
30 MHz.

--
Telamon
Ventura, California