Simple Dipole Antenna

[eco32 27]

Prototyping ongoing

[eco32 27]

I have two same grids, lets fin out how it will be in thi  combination (simple ilustration):

(simulation without optymalization shows inceasing gain from 17.2dBi to 19.6dBi)

[Admin 2561]

,,,where did you get this from? - such a thing is not possible...???!!!

[eco32 27]

1 hour ago, Admin said:

such a thing is not possible...???!!!

That's what my fellow senior radio amateurs tell to me

 

[eco32 27]

Measured very roughly, when the dimensions of the system are accurately measured the results will be different

Thats the basic grid - 17.3 dBi

 

That's double grid: 19.8dBi

 

option B -  it does not work: 16.9dBi

 

 

conclusion: doubling the reflector area gives ~~~~ 2.5dBi or more of the gain.

 

I will show real pictures later, will be mechanically difficult.

I think I can get a few dB more by improving the feed.

Edited June 13, 2023 by eco32

[Admin 2561]

,,,this is a bit stupid..!!
,,,you'd better use a parabolic offset...!!!

[eco32 27]

9 minutes ago, Admin said:

,,,this is a bit stupid..!!
 

This requires an explanation as to why you think it is stupid.

 

11 minutes ago, Admin said:

,,,you'd better use a parabolic offset...!!!

Of course not, such a grid reflector is best for dipole feed that have parabolas smaller than 10xlambda

BTW, it is prototypingc, parabolic offset will be consider in other project. Here we consider the "siple dipole" feed and exploration, what we can do. @Admin do you agree with me?

 

 

 

 

[Admin 2561]

[eco32 27]

It was concept picture,  it has one focal point

[eco32 27]

conclusion from simulations and from experiment:

shape is ok, gemetry is wrong!

 

Why?

The ratio of focal length to aperture size (ie., f/D) known as “f over D ratio” is an important parameter of parabolic reflector. Its value varies from 0.25 to 0.50.  calculator: https://satlex.de/en/fdratio-params.html?diam=90&depth=15

in my case is  f/D = 0.16 => Geometry is wrong - may it be that with other type of feed will be more profitable. Any parabolic antenna larger than 120cm is horrendously expensive, building big grid antennas is reasonable.

Example from Czech Republic: https://www.ok2kkw.com/wsjt2006/23cm2008.htm also for Earth–Moon–Earth communication (EME).

 

 

 

Grid vs double grid with siple dipole fed without small  reflector as case  above 13.5dBi VS 17dBi

 

 

 

I DID IT, AND YOU DONT HAVE TO!

 

 

[Admin 2561]

,,,the best f/D=0,6...!!!

[eco32 27]

Simple design with a corner reflector. 14dB, 10dB in the main direction, with additional  work with  the elements, you can probably improve the main beam. The structure is similar to my latest grid (17dBi), but simpler. Important detail : standard model  feed was changed to revers direction of radiation - director is Reflectors and reflector is director. Useful when you don't want to build a parabola

 

[Admin 2561]

,,,eco32, what program do you use for simulation...!!!

[eco32 27]

 

19 minutes ago, Admin said:

,,,eco32, what program do you use for simulation...!!!

Matlab (not yet able to use CST)

[eco32 27]

two dilpes with corner reflector: Gain increases, but at the expense of side lobes, in some applications this is unacceptable

details: Yagi feed is reversed and it has two reflectors

 

 

side lobes:

how it looks in "normal mode:, feed litle yagi was not reversed:

design:

patern

 

Edited November 15, 2023 by eco32

[Admin 2561]

,,,executes a single reflector with two antennas spaced at a distance greater than 143 mm between them...!!!

[eco32 27]

On 15.11.2023 at 4:04 PM, Admin said:

,,,executes a single reflector with two antennas spaced at a distance greater than 143 mm between them...!!!

10dBi in main direction, same a single dipole with corner reflector

Edited November 16, 2023 by eco32