Ground Rod Selection
 

On Sat, 22 Apr 2006 20:43:12 GMT, Telamon
wrote:

In article ,
Monroe wrote:

As a lone time listener but relative newbie to the tech, I've been
educating myself on system basics including ground questions.
Currently using a marginal 1.0 m steel post as a ground for a
shortwave Rx application. Intention is to upgrade to a 8 - 10 ft
ground rod (the only ground off of a 9:1 balun - post ground and balun
bracket - that a coax feedline connects with the Rx; this associated
with an inverted "L" antenna). I've read plenty of references to
copper rod or copper clad ground rods but I've yet to have any local
suppliers recognize this (let alone be able to supply). Standard
availability in my area are galvanized steel ground rods. Are these
of equivalent quality?

Grounds are very important for single wire antennas. They are
unimportant for balanced antennas like dipoles.

If you have a single wire like your inverted L then the ground is
important because it is only half the antenna. The ground is the other
half.

How well the ground rods work depends on the ground conductivity so the
bigger rod may make an improvement or it may not.

A better thing to do other rather than pound in another ground rod
would be to add a ground radial. To test this without much pain attach
a wire to the ground stake with a clamp and run it on top of the ground
underneath your current antenna. Check out the difference it makes on
your reception on several stations on different bands to see if it
makes an improvement.

If the wire laying on the ground makes a significant improvement then
you take the effort to dig a shallow trench and bury it.

The ground wire, even on a single wire antenna, may make little
difference listening wise. I have an inverted L on 20 meters; the
ground makes a huge difference on transmit, bringing down the SWR; but
on receive, I hear no difference whether the ground is attached or
not.

bob
k5qwg

Ground Rod Selection
 

In article ,
Bob Miller wrote:

On Sat, 22 Apr 2006 20:43:12 GMT, Telamon
wrote:

In article ,
Monroe wrote:

As a lone time listener but relative newbie to the tech, I've been
educating myself on system basics including ground questions.
Currently using a marginal 1.0 m steel post as a ground for a
shortwave Rx application. Intention is to upgrade to a 8 - 10 ft
ground rod (the only ground off of a 9:1 balun - post ground and balun
bracket - that a coax feedline connects with the Rx; this associated
with an inverted "L" antenna). I've read plenty of references to
copper rod or copper clad ground rods but I've yet to have any local
suppliers recognize this (let alone be able to supply). Standard
availability in my area are galvanized steel ground rods. Are these
of equivalent quality?

Grounds are very important for single wire antennas. They are
unimportant for balanced antennas like dipoles.

If you have a single wire like your inverted L then the ground is
important because it is only half the antenna. The ground is the other
half.

How well the ground rods work depends on the ground conductivity so the
bigger rod may make an improvement or it may not.

A better thing to do other rather than pound in another ground rod
would be to add a ground radial. To test this without much pain attach
a wire to the ground stake with a clamp and run it on top of the ground
underneath your current antenna. Check out the difference it makes on
your reception on several stations on different bands to see if it
makes an improvement.

If the wire laying on the ground makes a significant improvement then
you take the effort to dig a shallow trench and bury it.

The ground wire, even on a single wire antenna, may make little
difference listening wise. I have an inverted L on 20 meters; the
ground makes a huge difference on transmit, bringing down the SWR; but
on receive, I hear no difference whether the ground is attached or
not.

I don't know what your situation is so I can't comment on it. I have
done the experimentation and found it makes a huge difference. It could
be that your equipment grounded through the AC mains was enough for
reception. This will be a poor solution in my area due to the fact that
I live in town and the noise level on the AC mains is high.

Basic circuit theory requires that current travels in a loop. No power
flows in an open circuit. People recognize this obvious fact when
considering DC circuits but for some reason it is forgotten when it
comes to RF. The single wire of an Marconi type antenna is half the RF
circuit where ground is the other half. The receiver input is across
the antenna wire and ground.

A Hertzian antenna such as a dipole has two elements that develop the
voltage across the receiver input so an RF ground becomes superfluous.

In any event I proposed a painless way for the OP to test whether a
ground radial will help or not. I don't know what the soil conductivity
is where the OP lives so I can't advise whether another ground rod will
help or not but if an RF ground improvement can be made at the antenna
location over the installed rod then the radial attached to the
installed ground rod will make a significant difference.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On 23 Apr 2006 00:38:18 -0700, "RHF"
wrote:

For One and All,

Per "Telamon" - A Hertzian Antenna such as a Dipole has two elements
that develop the Voltage across the Receiver Input
- - - So an RF Ground becomes superfluous.

This Statement may be True a the specific Frequency that
the Dipole is Designed to Operate at {Resonance} .

"IS" this Statement always True at other Frequencies that
the Dipole was NOT Designed to Operate at {Non-Resonant} ?

QUESTION - Does a "Non-Resonant" Dipole Antenna work better
{Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
http://groups.yahoo.com/group/Shortw...a/message/9189

i want to know - cause iane ~ RHF
.
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf
.
I suggest you find a nice copy of the ARRL Antenna book and put it in
your ****ter for a few months.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On Sun, 23 Apr 2006 12:37:43 GMT, David wrote:

On 23 Apr 2006 00:38:18 -0700, "RHF"
wrote:

For One and All,

Per "Telamon" - A Hertzian Antenna such as a Dipole has two elements
that develop the Voltage across the Receiver Input
- - - So an RF Ground becomes superfluous.

This Statement may be True a the specific Frequency that
the Dipole is Designed to Operate at {Resonance} .

"IS" this Statement always True at other Frequencies that
the Dipole was NOT Designed to Operate at {Non-Resonant} ?

QUESTION - Does a "Non-Resonant" Dipole Antenna work better
{Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
http://groups.yahoo.com/group/Shortw...a/message/9189

i want to know - cause iane ~ RHF
.
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf
.
I suggest you find a nice copy of the ARRL Antenna book and put it in
your ****ter for a few months.

Yes, please... see:

http://www.arrl.org/catalog/?categor... gation&words=

bob
k5qwg

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On Sun, 23 Apr 2006 13:28:39 GMT, Bob Miller
wrote:


SWL Antenna Group = http://tinyurl.com/ogvcf
.
I suggest you find a nice copy of the ARRL Antenna book and put it in
your ****ter for a few months.

Yes, please... see:

http://www.arrl.org/catalog/?categor... gation&words=

bob
k5qwg

Even an old used one will work. The Quadrifilar Helix doesn't come up
much on this group.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

"David" wrote in message

The Quadrifilar Helix doesn't come up
much on this group.


That's because it's a shortwave forum.


--

Regards
B.H.

Brian's Radio Universe
http://webpages.charter.net/brianhill/500.htm

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On Sun, 23 Apr 2006 10:10:30 -0500, "Brian Hill" wrote:


"David" wrote in message

The Quadrifilar Helix doesn't come up
much on this group.


That's because it's a shortwave forum.

A forum you say? I'm agin 'em.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On 23 Apr 2006 00:38:18 -0700, "RHF"
wrote:

For One and All,

Per "Telamon" - A Hertzian Antenna such as a Dipole has two elements
that develop the Voltage across the Receiver Input
- - - So an RF Ground becomes superfluous.

This Statement may be True a the specific Frequency that
the Dipole is Designed to Operate at {Resonance} .

"IS" this Statement always True at other Frequencies that
the Dipole was NOT Designed to Operate at {Non-Resonant} ?
Certainly is, the point is a dipole is a balanced antenna, i.e. a
signal impinging on the antenna will have two components that 180
degrees out of phase. Thing about which end of each half the feed
comes from. So one side will always be the opposite orientation from
the other side.

All that happens when the antenna is not resonant, is the effective
impedance changes, and will contain a reactive component. That
usually reduces the power transfered from the antenna to the front end
of the receiver.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better
{Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
http://groups.yahoo.com/group/Shortw...a/message/9189

i want to know - cause iane ~ RHF
.
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf
.
.
. .
.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

David - U may be for'em
I B agin'em :o) ~ RHF

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

MW - Thank You for your Answer ~ RHF

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article ,
matt weber wrote:

On 23 Apr 2006 00:38:18 -0700, "RHF"
wrote:

For One and All,

Per "Telamon" - A Hertzian Antenna such as a Dipole has two elements
that develop the Voltage across the Receiver Input
- - - So an RF Ground becomes superfluous.

This Statement may be True a the specific Frequency that
the Dipole is Designed to Operate at {Resonance} .

"IS" this Statement always True at other Frequencies that
the Dipole was NOT Designed to Operate at {Non-Resonant} ?
Certainly is, the point is a dipole is a balanced antenna, i.e. a
signal impinging on the antenna will have two components that 180
degrees out of phase. Thing about which end of each half the feed
comes from. So one side will always be the opposite orientation from
the other side.

All that happens when the antenna is not resonant, is the effective
impedance changes, and will contain a reactive component. That
usually reduces the power transfered from the antenna to the front end
of the receiver.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better
{Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
http://groups.yahoo.com/group/Shortw...a/message/9189

i want to know - cause iane ~ RHF
.
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf

Matt is explanation correct but I would like to add a little more
information on what happens on receive. If the dipole is a half
wavelength then the antenna output is at the maximum voltage point.
This a resonance point because the EM wave is 2X length of the elements
electrical length. The elements are 1/4 wavelength each.

When the EM wave is longer or shorter than the antenna's electrical
length the antenna output is not at the maximum point so the output
decreases. When you get to a frequency 2X what the 1/2 wave dipole is
cut for the antenna output point is at zero volts and the antenna will
appear to be deaf at that point.

It is easy to visualize what is happening. Draw a sine wave and below
it draw a line under the positive excursion, zero volts to max positive
and then back to zero volts. Make a break in the middle of the line.
These two break points in the middle of the line are the 1/2 wave
dipole output. Each line segment is 1/4 wave length. You can see the
voltage is at maximum in the middle of the line and zero volts at the
ends of the line.

Now do the same thing for a 1 wave length dipole. Draw a line under the
entire sine wave and make the break in the middle of the line. Each
line segment is 1/2 wave. Notice that now the antenna output is at the
zero volt point where you go from positive excursion to negative
excursion and so there is no voltage at the antenna output.

Now all you need to visualize is that going from 1/2 to 1 wave length
you go from maximum possible output to nothing. You can't see radio EM
waves but why things work as they do is not hard to visualize.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

David :

Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf
.
I suggest you find a nice copy of the ARRL Antenna book and put it in
your ****ter for a few months.

Painful. Is it softcover edition?

--
Bob

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On Sun, 23 Apr 2006 21:31:11 GMT, Telamon
wrote:

In article ,
matt weber wrote:

On 23 Apr 2006 00:38:18 -0700, "RHF"
wrote:

For One and All,

Per "Telamon" - A Hertzian Antenna such as a Dipole has two elements
that develop the Voltage across the Receiver Input
- - - So an RF Ground becomes superfluous.

This Statement may be True a the specific Frequency that
the Dipole is Designed to Operate at {Resonance} .

"IS" this Statement always True at other Frequencies that
the Dipole was NOT Designed to Operate at {Non-Resonant} ?
Certainly is, the point is a dipole is a balanced antenna, i.e. a
signal impinging on the antenna will have two components that 180
degrees out of phase. Thing about which end of each half the feed
comes from. So one side will always be the opposite orientation from
the other side.

All that happens when the antenna is not resonant, is the effective
impedance changes, and will contain a reactive component. That
usually reduces the power transfered from the antenna to the front end
of the receiver.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better
{Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
http://groups.yahoo.com/group/Shortw...a/message/9189

i want to know - cause iane ~ RHF
.
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf

Matt is explanation correct but I would like to add a little more
information on what happens on receive. If the dipole is a half
wavelength then the antenna output is at the maximum voltage point.
This a resonance point because the EM wave is 2X length of the elements
electrical length. The elements are 1/4 wavelength each.

When the EM wave is longer or shorter than the antenna's electrical
length the antenna output is not at the maximum point so the output
decreases. When you get to a frequency 2X what the 1/2 wave dipole is
cut for the antenna output point is at zero volts and the antenna will
appear to be deaf at that point.

It is easy to visualize what is happening. Draw a sine wave and below
it draw a line under the positive excursion, zero volts to max positive
and then back to zero volts. Make a break in the middle of the line.
These two break points in the middle of the line are the 1/2 wave
dipole output. Each line segment is 1/4 wave length. You can see the
voltage is at maximum in the middle of the line and zero volts at the
ends of the line.

Now do the same thing for a 1 wave length dipole. Draw a line under the
entire sine wave and make the break in the middle of the line. Each
line segment is 1/2 wave. Notice that now the antenna output is at the
zero volt point where you go from positive excursion to negative
excursion and so there is no voltage at the antenna output.

Now all you need to visualize is that going from 1/2 to 1 wave length
you go from maximum possible output to nothing. You can't see radio EM
waves but why things work as they do is not hard to visualize.

What about the virtual capacitor?

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

Bob wrote:
David :
Shortwave Listener Antennas = http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group = http://tinyurl.com/ogvcf
.
I suggest you find a nice copy of the ARRL Antenna book and put it in
your ****ter for a few months.

Painful. Is it softcover edition?

Look at it this way; you won't need TP for your bunghole.

--
All relevant people are pertinent.
All rude people are impertinent.
Therefore, no rude people are relevant.
-- Solomon W. Golomb

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

Telamon wrote in
:

In article , "Brian Hill" wrote:

"David" wrote in message

The Quadrifilar Helix doesn't come up
much on this group.


That's because it's a shortwave forum.

That's because they would be to big for most people to construct for
short wave and they are very directional and so they would have to be
rotated.


Oh my.

SC

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

FO&A - But their is another work around
'trick' answer - out there !

So I want to Rig my cut-to-order Dipole Antenna to use
for general across-the-bands Shortwave Listening.

First - Don't Think of It as a Dipole . . .

QUESTION - Does a"Non-Resonant" Dipole Antenna work better {Be...
 

Brian,I am going to float my Sunn thingy over to you.Dontchoo worry.I
will get it to you.
cuhulin

Ground Rod Selection
 

I need to email Mary DuRose over yonder in the Sydney,OZ area.She is
originally from Kansas.I lived in Salina,Kansas in 1957.She is from the
Wichita area,or somewhere around there.My old brother in law has an Air
Force buddy in Topeka,Kansas.His buddy used to work his Farm near
Wetmore,Kansas.I am just as much Kansan as any other Kansans out there.
cuhulin

QUESTION - Does a"Non-Resonant" Dipole Antenna work better {Be...
 

All I want to do is ''cut one''
cuhulin

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article .com,
"RHF" wrote:

FO&A - But their is another work around
'trick' answer - out there !

So I want to Rig my cut-to-order Dipole Antenna to use
for general across-the-bands Shortwave Listening.

First - Don't Think of It as a Dipole . . .

I prefer antennas for reception closer to the space impedance around it.
A ball park antenna type is a folded dipole. It can be made cheaply with
300 ohm twin lead transmission line and 4:1 BALUNs to connect it to 50
ohm coax is also cheap and common.

Another advantage is it is grounded so static charge pickup is shunted.

There is a trick to make it perform better on bands other than what it
is cut for using shorts at a specific distance from the ends depending
on the band for which it is cut.

You can use the dipole concept by using several cut for different bands
tied together at the antenna output. For this to work well the
paralleled elements need to have a relationship to each other that
prevents the energy picked up from one element flowing into another
element.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article . com,
"RHF" wrote:

MW - Thank You for your Answer ~ RHF
.
But their is another work around 'trick' answer
- out there . . .

I don't care for the language of "trick answers" or "black magic" when
it comes to RF or antennas. RF and antennas behavior can be understood.
This understanding can be shallow or deep depending on what your needs
are or what you are trying to accomplish. Here in this news group where
we are interested in short wave reception we only need to understand
basic antenna and grounding behavior where simple algebraic formulas to
calculate antenna element lengths are easily found on the Internet.

Depending on your location some antennas will work better for you than
others and so is one level of investigation.

1. Determine the antenna type for your application and location.
2. Find the formula to determine the element lengths.
3. Using inexpensive wire, cable, insulators to build it.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On Tue, 25 Apr 2006 20:05:26 GMT, Telamon
wrote:

In article .com,
"RHF" wrote:

FO&A - But their is another work around
'trick' answer - out there !

So I want to Rig my cut-to-order Dipole Antenna to use
for general across-the-bands Shortwave Listening.

First - Don't Think of It as a Dipole . . .

I prefer antennas for reception closer to the space impedance around it.
A ball park antenna type is a folded dipole. It can be made cheaply with
300 ohm twin lead transmission line and 4:1 BALUNs to connect it to 50
ohm coax is also cheap and common.

Another advantage is it is grounded so static charge pickup is shunted.

There is a trick to make it perform better on bands other than what it
is cut for using shorts at a specific distance from the ends depending
on the band for which it is cut.

You can use the dipole concept by using several cut for different bands
tied together at the antenna output. For this to work well the
paralleled elements need to have a relationship to each other that
prevents the energy picked up from one element flowing into another
element.

300 Ohms matches better to 75 Ohm line with a 4:1 transformer.

4 X 75 = 300

4 X 50 = 200

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article om,
"RHF" wrote:

Telamon - The Trick is not in the Antenna but . . .
in the application and implementation of it use in
a manner for which it was not originally designed.

On its face that statement does not make a lot of sense. Engineering is
applying mathematical and scientific concepts to an application. You
could use a spoon as a shovel for digging a trench but it would not work
well. An antenna is designed for a purpose of receiving of transmitting
on some range of frequencies and it generally won't work well in other
applications.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article .com,
"RHF" wrote:

So I want to Rig my cut-to-order Dipole Antenna to use
for general across-the-bands Shortwave Listening.

First - Don't Think of It as a Dipole . . .

Think of it as Two Horizontal Wire Antennas that are fed
with a Pair of Matched Lines {Ladder Line - Twin Lead - etc}


You have three paragraphs that appear to cover three different issues
with no attribution so I don't know how to respond to this post.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

David - Now you are thinking :o) ~ RHF

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article . com,
"RHF" wrote:

So I want to Rig my cut-to-order Dipole Antenna to use
for general across-the-bands Shortwave Listening.

First - Don't Think of It as a Dipole . . .

Think of it as Two Horizontal Wire Antennas that are fed
with a Pair of Matched Lines {Ladder Line - Twin Lead - etc}

Second -Taking the two (a pair of) feed-in-line Wires and
Connecting them together at the "Antenna" HI-Z (500 Ohm)
{Red} Terminal of my Radio / Receiver.

Third - Then I connect my Ground Wire to the "Ground"
HI-Z (500 Ohm) {Black} Terminal of my Radio / Receiver.

The impedance does not match up that well as a 300 ohm transmission
line to 500 high impedance input on most radios but it might work well
in low noise situation. Anyone ever try this?

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

On Fri, 28 Apr 2006 17:03:30 GMT, Telamon
wrote:

In article . com,
"RHF" wrote:

So I want to Rig my cut-to-order Dipole Antenna to use
for general across-the-bands Shortwave Listening.

First - Don't Think of It as a Dipole . . .

Think of it as Two Horizontal Wire Antennas that are fed
with a Pair of Matched Lines {Ladder Line - Twin Lead - etc}

Second -Taking the two (a pair of) feed-in-line Wires and
Connecting them together at the "Antenna" HI-Z (500 Ohm)
{Red} Terminal of my Radio / Receiver.

Third - Then I connect my Ground Wire to the "Ground"
HI-Z (500 Ohm) {Black} Terminal of my Radio / Receiver.

The impedance does not match up that well as a 300 ohm transmission
line to 500 high impedance input on most radios but it might work well
in low noise situation. Anyone ever try this?

He's talking about shorting both legs together I think. Most Hi-Z
inputs work OK with 300 or 450 Ohm line, as well as monopole wires.

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article .com,
"RHF" wrote:

FWIW :

Starting with a Single Band Dipole Antenna :

First - Both the Wires of the Ladder Line / Twin Lead / Twisted Pair
are connected to "Antenna" HI-Z (500 Ohm) {Red} Terminal of the
Radio / Receiver.

Second - The Ground Wire is connected to the "Ground"
HI-Z (500 Ohm) {Black} Terminal of the Radio / Receiver.

For a "Receive Only" Shortwave Listening (SWL) Antenna
it works OK.

For use as a Transmitting Antenna then an Antenna Tuning
Unit (ATU) "Trans-Match" would be required.

SO... WHAT KIND OF ANTENNA IS IT ?

At the Top the Antenna has two Horizontal Arms that are
Part of the Wire Antenna Element.

The two feed-in-line Wires can be considered as simply
feed-in-line or as part of the Antenna.

David says that this is a Top Loaded Vertical.

I believe some refer to it as a Double Extended Zepp Antenna ?
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=7682

I tent to think of it as a Twin Inverted "L" Antenna -or-
opposing classic LongWire {Random Wire} Antennas.

WHAT WOULD YOU CALL THIS MISS WIRED DIPOLE ?

Sorry I misread your previous post.

Any time you have one element for the antenna and ground for the other
side of a radio input you have a common voltage mode antenna.

There are two basic voltage antenna types Marconi and Hertzian. The
Marconi is single element and ground common mode antenna. The basic
Hertzian is two elements and balanced making it a differential mode.

Depending on dimensions of the horizontal and vertical parts your
proposed antenna could be a top loaded vertical. Change the dimensions
and it could be an inverted L. Just understand that the mode the
antenna operates in does not change. The vertical portion can connect
to the horizontal section at the end, middle, or somewhere in between
and it still is a common mode antenna whatever the resulting shape.

Call it the RHF special.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

Telamon,

At least according to my reads over the years.
Amateurs have been hooking-up their Dipole
Antennas this way for decades using an ATU.

The Twin (2) feed-in-lines would effective make them
a thicker single conductor.

Assuming that the Twin (2) feed-in-line are mostly Vertical
and the Splight Top Wires (2) are mostly Horizontal

Then what you got is . . . {Marconi}
A Moderate Size Vertical Antenna with a Big Top Hat.
[ Gee isn't that what David Said ? ]

iane ~ RHF

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

In article . com,
"RHF" wrote:

Telamon,

At least according to my reads over the years.
Amateurs have been hooking-up their Dipole
Antennas this way for decades using an ATU.

The Twin (2) feed-in-lines would effective make them
a thicker single conductor.

Assuming that the Twin (2) feed-in-line are mostly Vertical
and the Splight Top Wires (2) are mostly Horizontal

Then what you got is . . . {Marconi}
A Moderate Size Vertical Antenna with a Big Top Hat.
[ Gee isn't that what David Said ? ]


A tuner to fix VSWR antenna problems is not a good way to go. It is OK
to use a shack tuner for small values of VSWR so the transmitter finals
don't have to burn the added reflected power or cause instability. The
tuner in the shack does not cause the antenna to perform better.

Because hams operate on a range of frequencies in a band the strategy
is to have it resonant in the center of the band so the VSWR is about
1:1 there. Then it is about the same at the band ends say for example
1.5:1. Now the tuning unit is not needed at all in the band center and
only has to compensate small values of VSWR at the band edges. This is
an acceptable approach to using a shack tuning unit.

Now before some cleaver but silly person mentions that a certain length
of coax will cause the shack tuning unit antenna side to actually
represent the antenna impedance don't bother. While this is true it
only represents certain operating points and is not usable across a
band or bands on a multi-band antenna.

In order to get better antenna efficiency you need a tuning unit that
actually causes the antennas resonant frequency to change as opposed to
a variable impedance matching unit in the shack. This means the tuner
has to be a part of the antenna and that can't happen in the shack.

Now do you see the problem this presents for SW listening 3 to 30 MHz?

***
Yes, paralleling conductors makes them look like a bigger conductor
because RF current travels on the conductor surface. Generally you want
a better circular symmetry than two wires provide. Three would be better
as a minimum. Generally three to five is a good number. This is of
course diameter and frequency dependent number.

***
I would not know what Dave said. He is in the kill file because he keeps
going off the deep end.

Antennas operate in different modes and they can be classified in that
way. Pay attention to how they operate so you can determine what will
work for you depending on your location and needs.

--
Telamon
Ventura, California

QUESTION - Does a "Non-Resonant" Dipole Antenna work better {Benefit} when a Receiver is RF Grounded in the Shack ? ? ?
 

Telamon,

I would agree with just about everything that you wrote.

"Now do you see the problem this presents
for SW listening 3 to 30 MHz?"

YES - But for the Shortwave Listener (SWL) using
the Antenna (any antenna) the VSWR could be 1:1
or 8:1 (Doubled (2x) and Re-Doubled (2x2) and then
Doubled Again (2x2x2) - - - Because - - -
The SWLs are using their Antenna for "Receive Only"
and the Radio / Receiver's AGC Circuit or more will
function to compensate for the differences caused
by the variation in VSWR as the frequency changes
from 3 MHz to 30 MHz.

IMHO _ The Shortwave Listener like the Amateur who
puts the ATU at the Antenna before the feed-in-line to
get the most out of their Transmitting Antenna; should
put a Matching Transformer at the Antenna before the
feed-in-line to get the most out of their "Receive Only"
Antenna.

it's not science - just my opinion - iane ~ RHF