On 19 Mar 2006 19:01:25 -0800, "RHF"
wrote:

A 72-ohm fanned dipole connected to a single coax feed going to a
50-ohm input doesn't need a balun, especially a 4-1 jobbie.

bob
k5qwg

How...,

1. For a dipole skip the 4:1 balun - go straight to the coax
-R- Good advise for a Ham using the Dipole for a Specific
Amateur Radio Meter Band - But for a Shortwave Listener
(SWL) who is trying to use the Dipole as a general Antenna
for All-SWL-Band reception the 4:1 Balun gives them more
Listening-ability-across-the-Bands.
REMEMBER - This is a Three Band : 49 & 31 & 22 Meter
Bands Shortwave Listener (SWL) "Receive Only" Tri-Band
Dipole {Wire} Antenna built on a On-the-Fence

2. or use a 1:1 unun.
-R- An UnUn with a Dipole ?
- - - Dipole to Twin Lead / Ladder Line = BalBal
- - - Dipole to Coax Cable = BalUn

3. If you were building a folded dipole the 4:1 balun
would be more appropriate.
-R- Again this is a Three Band : 49 & 31 & 22 Meter
Bands Shortwave Listener (SWL) "Receive Only"
Tri-Band Dipole {Wire} Antenna built on a On-the-Fence
The object of the 4:1 Balun is to intergrate the Signals
developed by the Three Dipole Antenna Elements into
the Single Coax Cable Feed-in-Line and provide better
Across-the-Shortwave-Bands frequency coverage.

4. You can ground or not ground the dipole;
it is a balanced antenna so grounding is a
matter of lightning protection & providing a
path for the static electricity to drain
- a better path than draining to the radio.
-R- Lightning Protection and a Static Electricity
'drain' Path are always two good things to achieve
with any Shortwave Listener's (SWL) Antenna.

5. I guess the dipole that's 1 foot above the
ground is for 'ground wave' reception 8-}
-R- Wave Goodbye "How..."

FWIW - A Dipole On-the-Fence would not be my first
choice as a Shortwave Listener's (SWL) Antenna.
But what can you do - If the ONLY place that you can
build an Antenna is On-the-Fence ? ? ? and you don't
have the Money for a Wellbrook Loop Antenna ? ? ?
Plus someone has convinced you that the ONLY
Antenna that is worth having is a Dipole - because it
is a complete Antenna that does not require a ground
to work. - - - So now all you know is that you have to
build a Dipole Antenna and it's got to fit On-the-Fence [.]


right now i am beginning to feel a little di-pole-er - iane ~ RHF
.
.
. .
.

BM [K5QWG],

What you say is correct if the Fan Dipole is being
used properly as a Single Band Amateur Antenna.

How Ever ! ! ! ) Take the same Antenna and . . .
[ Remember we have an Antenna built On-the-Fence
and for what ever reason {or lack of understanding}
the Shortwave Listener (SWL) has decided the a
Dipole is the only thing {Antenna} that they want.
Plus the want a Mutli-Band Antenna to cover a few
of the Shortwave Bands for Broad-Cast Program
Listening (BCL) ]

SO HERE WE GO AGAIN - - - - - - - - - - - - - -
This is a Three Band : 49 & 31 & 22 Meter Bands
Shortwave Listener (SWL) "Receive Only" Tri-Band
Dipole {Wire} Antenna built on a On-the-Fence
Question What Do We Do To Make It 'perfrom' ? ? ?
? To Perform - Or Not To Perform - - - Is That a Question ?
A little better across the Shortwave Bands so we can
"HEAR" a little of everything from 1.8 MHz to 30 MHz.
Not a good answer but never the less a fair answer is
the 4:1 Balun to 'smooth-out' the impedance mismatches
from the Three (3) Dipole Antenna Elements and provide
a fair 'match' from the three of them across the Shortwave
Bands; know that they are One-Foot, Three-Feet and
Five-Feet above the ground when Idealy they would be :
49m = 38.5 Feet above AGL
31m = 24.5 Feet above AGL
22m = 17.1 Feet above AGL

alas - it is an imperfect world - iane ~ RHF

On 21 Mar 2006 19:41:42 -0800, "RHF"
wrote:


SO HERE WE GO AGAIN - - - - - - - - - - - - - -
This is a Three Band : 49 & 31 & 22 Meter Bands
Shortwave Listener (SWL) "Receive Only" Tri-Band
Dipole {Wire} Antenna built on a On-the-Fence
Question What Do We Do To Make It 'perfrom' ? ? ?
? To Perform - Or Not To Perform - - - Is That a Question ?
A little better across the Shortwave Bands so we can
"HEAR" a little of everything from 1.8 MHz to 30 MHz.
Not a good answer but never the less a fair answer is
the 4:1 Balun to 'smooth-out' the impedance mismatches
from the Three (3) Dipole Antenna Elements and provide
a fair 'match' from the three of them across the Shortwave
Bands; know that they are One-Foot, Three-Feet and
Five-Feet above the ground when Idealy they would be :
49m = 38.5 Feet above AGL
31m = 24.5 Feet above AGL
22m = 17.1 Feet above AGL

alas - it is an imperfect world - iane ~ RHF
.
.
. .


I took into consideraton that there are three dipoles here, connected
to a single transmission line -- so hopefully each will be within
yelling distance, impedance wise, of 75 ohms, so there's no need for a
4-1 balun to a 50 ohm input.

Unless you want to transpose 75 ohms to about 20 ohms?

And if the antenna is less than a half-wavelength high at frequency,
on a fence so to speak, the impedance could be anywhere between 40 and
90 ohms, according to chap. 20 of the ARRL handbook. Still no need for
a 4-1 balun. Maybe a 1 to 1 choke balun, to sop up noise, but a 4-1?

What is it, this high religious SW fever for baluns in this group :-)

bob
k5qwg

In article ,
Bob Miller wrote:

On 21 Mar 2006 19:41:42 -0800, "RHF"
wrote:


SO HERE WE GO AGAIN - - - - - - - - - - - - - -
This is a Three Band : 49 & 31 & 22 Meter Bands
Shortwave Listener (SWL) "Receive Only" Tri-Band
Dipole {Wire} Antenna built on a On-the-Fence
Question What Do We Do To Make It 'perfrom' ? ? ?
? To Perform - Or Not To Perform - - - Is That a Question ?
A little better across the Shortwave Bands so we can
"HEAR" a little of everything from 1.8 MHz to 30 MHz.
Not a good answer but never the less a fair answer is
the 4:1 Balun to 'smooth-out' the impedance mismatches
from the Three (3) Dipole Antenna Elements and provide
a fair 'match' from the three of them across the Shortwave
Bands; know that they are One-Foot, Three-Feet and
Five-Feet above the ground when Idealy they would be :
49m = 38.5 Feet above AGL
31m = 24.5 Feet above AGL
22m = 17.1 Feet above AGL


I took into consideraton that there are three dipoles here, connected
to a single transmission line -- so hopefully each will be within
yelling distance, impedance wise, of 75 ohms, so there's no need for a
4-1 balun to a 50 ohm input.

Unless you want to transpose 75 ohms to about 20 ohms?

And if the antenna is less than a half-wavelength high at frequency,
on a fence so to speak, the impedance could be anywhere between 40 and
90 ohms, according to chap. 20 of the ARRL handbook. Still no need for
a 4-1 balun. Maybe a 1 to 1 choke balun, to sop up noise, but a 4-1?

What is it, this high religious SW fever for baluns in this group :-)

It's a way to current terminate a coax so it is not completely (100%)
dependent on the the antenna impedance for the source termination.

You want to have lengths of the dipoles to be high impedance respective
to each other so the characteristic impedance of the sum says around the
72 to 50 ohm range. You would then want to then use a 1:1 BALUN.

--
Telamon
Ventura, California

On Wed, 22 Mar 2006 21:01:37 GMT, Telamon
wrote:

In article ,
Bob Miller wrote:

On 21 Mar 2006 19:41:42 -0800, "RHF"
wrote:


SO HERE WE GO AGAIN - - - - - - - - - - - - - -
This is a Three Band : 49 & 31 & 22 Meter Bands
Shortwave Listener (SWL) "Receive Only" Tri-Band
Dipole {Wire} Antenna built on a On-the-Fence
Question What Do We Do To Make It 'perfrom' ? ? ?
? To Perform - Or Not To Perform - - - Is That a Question ?
A little better across the Shortwave Bands so we can
"HEAR" a little of everything from 1.8 MHz to 30 MHz.
Not a good answer but never the less a fair answer is
the 4:1 Balun to 'smooth-out' the impedance mismatches
from the Three (3) Dipole Antenna Elements and provide
a fair 'match' from the three of them across the Shortwave
Bands; know that they are One-Foot, Three-Feet and
Five-Feet above the ground when Idealy they would be :
49m = 38.5 Feet above AGL
31m = 24.5 Feet above AGL
22m = 17.1 Feet above AGL


I took into consideraton that there are three dipoles here, connected
to a single transmission line -- so hopefully each will be within
yelling distance, impedance wise, of 75 ohms, so there's no need for a
4-1 balun to a 50 ohm input.

Unless you want to transpose 75 ohms to about 20 ohms?

And if the antenna is less than a half-wavelength high at frequency,
on a fence so to speak, the impedance could be anywhere between 40 and
90 ohms, according to chap. 20 of the ARRL handbook. Still no need for
a 4-1 balun. Maybe a 1 to 1 choke balun, to sop up noise, but a 4-1?

What is it, this high religious SW fever for baluns in this group :-)

It's a way to current terminate a coax so it is not completely (100%)
dependent on the the antenna impedance for the source termination.

You want to have lengths of the dipoles to be high impedance respective
to each other so the characteristic impedance of the sum says around the
72 to 50 ohm range. You would then want to then use a 1:1 BALUN.


H-Y-P-O-C-R-I-T-E ALERT!!