j-pole 5/8 wave
 

Hello all,

As a new Novice amateur I am considering to build my first antenna.
I know that starting with a j-pole is simple and easy. However. I see many
plans on the internet.

One of interest is the stacked 5/8 wave j-pole.
I only see this in a stacked version. In a not stacked way I only see the
half wave version with a quarter stub.

Can a 5/8 wave length and 1/2 wave stub work as a real 5/8 wave antenna?

Looking forward for any suggestion!

j-pole 5/8 wave
 

michel wrote:
Hello all,

As a new Novice amateur I am considering to build my first antenna.
I know that starting with a j-pole is simple and easy. However. I see many
plans on the internet.

One of interest is the stacked 5/8 wave j-pole.
I only see this in a stacked version. In a not stacked way I only see the
half wave version with a quarter stub.

Can a 5/8 wave length and 1/2 wave stub work as a real 5/8 wave antenna?

Looking forward for any suggestion!





------------


The homemade (very crude) 1/2 wave with a 1/4 wave matching section that
I described in another article easily made great contacts from
Pennsville, NJ (Wilmington, DE) to Philadelphia on simplex with ease. It
was even indoors when I did it and I was running 10 watts or less. That
is about a 30 mile distance. Mine was constructed of two pieces of #8
aluminum grounding wire stuck into two holes drilled into a piece of 2x4
as a base, sitting on my table a few feet away from my rig inside of the
house. That was good enough for me to hold QSO's on FM and sideband with
all of my Philadelphia friends (WA3RXE and several others).


Ed Cregger

j-pole 5/8 wave
 

michel wrote:
Can a 5/8 wave length and 1/2 wave stub work as a real 5/8 wave antenna?

A 5/8WL needs inductive reactance to resonate it.
An inductive stub will do that but a 1/2WL stub
will not. FYI, for a 2x5/8WL dipole, a 0.2 WL
series section of 450 ohm ladder-line is a pretty
good match to 50 ohms.
--
73, Cecil http://www.w5dxp.com

j-pole 5/8 wave
 

"Cecil Moore" schreef in bericht
. net...
michel wrote:
Can a 5/8 wave length and 1/2 wave stub work as a real 5/8 wave antenna?

A 5/8WL needs inductive reactance to resonate it.
An inductive stub will do that but a 1/2WL stub
will not. FYI, for a 2x5/8WL dipole, a 0.2 WL
series section of 450 ohm ladder-line is a pretty
good match to 50 ohms.

In a simple way... I have a vertical radiator of 2 x 5/8 wave length. That
is serie with 450 ladder line one side connected to the radiated element and
the other to a groundplane will work?

j-pole 5/8 wave
 

michel wrote:
In a simple way... I have a vertical radiator of 2 x 5/8 wave length. That
is serie with 450 ladder line one side connected to the radiated element and
the other to a groundplane will work?

I cannot tell from your description what is your
exact configuration. Is this it? (fixed font)

GndPlane--+ +-------------------------------------
| | 1.25WL vertical monopole
| |
| |
| | 450 ohm ladder-line
| | to transmitter

Simple vertical monopoles should not be longer than
5/8WL.
--
73, Cecil http://www.w5dxp.com

j-pole 5/8 wave
 

"Cecil Moore" schreef in bericht
. ..
michel wrote:
In a simple way... I have a vertical radiator of 2 x 5/8 wave length.
That is serie with 450 ladder line one side connected to the radiated
element and the other to a groundplane will work?

I cannot tell from your description what is your
exact configuration. Is this it? (fixed font)

GndPlane--+ +-------------------------------------
| | 1.25WL vertical monopole
| |
| |
| | 450 ohm ladder-line
| | to transmitter

Hi Cecil,

In your first reply you talked about 2x 5/8 wave with 0,2 wave in serie to
50 ohm.
That is the same as in your example here? Or must we use it al the way up to
my transciever? I am still talking about 5/8 wave for 2 meters.

Michel

j-pole 5/8 wave
 

michel wrote:
In your first reply you talked about 2x 5/8 wave with 0,2 wave in series to
50 ohm.
That is the same as in your example here?

No, my first reply was about a 2x5/8WL dipole fed in
the center with 0.2WL of ladder-line and no ground plane.

Or must we use it al the way up to
my transciever? I am still talking about 5/8 wave for 2 meters.

You can turn the 2x5/8WL center-fed dipole vertical
in which case, like a vertical center-fed 1/2WL dipole,
it doesn't need a ground plane.
--
73, Cecil http://www.w5dxp.com

j-pole 5/8 wave
 

michel wrote:
Hello all,

As a new Novice amateur I am considering to build my first antenna.
I know that starting with a j-pole is simple and easy. However. I see many
plans on the internet.

One of interest is the stacked 5/8 wave j-pole.
I only see this in a stacked version. In a not stacked way I only see the
half wave version with a quarter stub.

Can a 5/8 wave length and 1/2 wave stub work as a real 5/8 wave antenna?

Looking forward for any suggestion!

I don't know what construction technique you have in mind, but I
prefer to build them from 1/2" copper pipe. If that's what you intend
to do, then just cut the vertical radiator 5/8ths instead of 1/2
lambda. Build the rest the same (1/4 wave stub). Attach your coax to
the stub section using hose clamps, and tune by sliding the clamps up
or down until you achieve best SWR. Works great.

ac6xg

j-pole 5/8 wave
 

I don't know what construction technique you have in mind, but I prefer to
build them from 1/2" copper pipe. If that's what you intend to do, then
just cut the vertical radiator 5/8ths instead of 1/2 lambda. Build the
rest the same (1/4 wave stub). Attach your coax to the stub section using
hose clamps, and tune by sliding the clamps up or down until you achieve
best SWR. Works great.

ac6xg


Should it be that simple? I understood from other posters that it will not
work with the 1/4 wave stub..
Maybe I must try it myself?

What I found is 2x5/8 wave with a 1/4 wave stub.. ?

j-pole 5/8 wave
 

michel wrote:
I don't know what construction technique you have in mind, but I prefer to
build them from 1/2" copper pipe. If that's what you intend to do, then
just cut the vertical radiator 5/8ths instead of 1/2 lambda. Build the
rest the same (1/4 wave stub). Attach your coax to the stub section using
hose clamps, and tune by sliding the clamps up or down until you achieve
best SWR. Works great.

ac6xg



Should it be that simple?

It can be.

I understood from other posters that it will not
work with the 1/4 wave stub..

For some posters, a view of the forest is obscured by trees. A j-pole
is a quarter wave stub with a 1/2 wave (or longer) radiator attached
to one side of the open end. The feed is connected nearer to the
shorted end of the stub. Build it and they (the QSOs) will come. Get
it up as high above the roof as you can.

ac6xg