eco32

It looks like my 90cm quassi dish (grid from 5GHz grid antenna) with dipole feed with coaxial splited balun has biger gain ans smaller dimeters Looks like 17dBi gain in loop is a naive wish of the author. Let me try. I have CST studio for a short time, I don't know how to use yet. Please be kind and share this model, I will try to change the diameters of the elements and distances one by one

additional materials [4] A Parasitic End-Fire Array of Circular Loop Elements [5] Optimum Design of Yagi Array of Loop Optimum Design of Yagi Array of Loop.pdf A Parasitic End-Fire Array of.pdf

Vivaldi in progres, Im waiting for bigger drill I do not know completely what the result will be, I make from garbage.

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!

how to finf focal point: you point the antenna towards the sun, and sliding cheet of paper (I couldn't find a better source to ilustrate) LASER use:

It was concept picture, it has one focal point

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

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.

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

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 has right @anoduck: You can use siple laser pointer to findout where your beam is radiating. focus point can be checked by peaper sheet and sun focus point can be checked by peaper sheet and sun. BTW: The sun generates a lot of noise and pointing the anena at the sun You can also adjust the focal point.

I have acces only to "A Novel Wideband Quasi-Yagi Antenna for Base-station Applications", the is no dimensions. From charts it looks like this is antenna for a ~2.3GHz and ~3.3GHz

Is there a director shape that works best, a square, a loop, a simple rectangle , (...)?

In my understanding of MIMO, these antennas transmit separate signals, +45 and -45degr, in the simulation should be considered separately and not together. Gain will be 6dBi, not 9dBi.

Prototyping ongoing

Design with slot or with coaxial splited balun - the reflector disc is smaller than the previous design, I guess that's the reason for the lower gain.

WOW! The antenna is very broadband! It Covers the entire 23cm band, this type of design is also suitable for LTE/5G I have read that for grid parabolic antennas the reflector can be narrower, it does not have to be a circle, it can be a rectangle with rounded corners With my firs 13dBi design, I made the QSO with 250mW over a distance of 8km using the reflection of a tall office building. (I have different grids: 600mmx400mm 13dBi, 700mm x 900mm 17dBi)

MIT Radiation Lab Series V12 Microwave Antenna Theory and Design 1949 chapter 8 Microwave dipole antennas and feeds https://www.scribd.com/document/35903457...and-Design#

This type of antenna is patented : US5191350 LOW WIND LOAD PARABOLIC ANTENNA, for more details check pdf file. US5191350 LOW WIND LOAD PARABOLIC ANTENNA.pdf

Thats grid with dipole rear feed with splited coaxial balun, basic version (1) with one reflector on the feed

Diameters for a 1296MHz Hi, it looks very good! Could You try diameters for a 1296MHz? lambda 127.118644 lamda 231.481481 13cm(inch) 13cm(inch) 13cm(mm) alfa 23cm 2+1/2 2.5 63.5 0.49953333 115.632716 11/64 0.171875 4.365625 0.03434292 7.94974923 1+1/4 1.25 31.75 0.24976667 57.816358 1+27/64 1.421875 36.115625 0.28410958 65.7661073 1+3/32 1.09375 27.78125 0.21854583 50.5893133 2+7/16 2.4375 61.9125 0.487045 112.741898 3/16 0.1875 4.7625 0.037465 8.6724537 15/16 0.9375 23.8125 0.187325 43.3622685 2+7/16 02-Jan 61.9125 0.487045 112.741898

something about thos antenna from 1968 The Radio Amateur's V.H.F. Manual - A Manual of Amateur Radio Communication on the Frequencies Above 50 Megacycles 1968 https://dokumen.pub/the-radio-amateurs-vhf-manual-a-manual-of-amateur-radio-communication-on-the-frequencies-above-50-megacycles-11th-ed.html (I will try do my own for a 1296MHz) From the description, it seems that it is not a "simple dipole" but a slot antenna.

It is based on Pacyfic Grid 917x720 and 15cm deep 5.6GHz grid antenna symulation + Yagi Uda in revers - directors works likea rediators (This is not a good representation, Matlab has big limitations) 1296MHZ => 17.3dBi oryginal grid antenna https://www.cyberbajt.pl/produkt/350/pacific-grid-56-ghz28-dbi.html

I cannot find a commercial implementation of such an "feed" also no publication with "rear dipole feed with two reflectors". May the name is very specific, google does not return anything meaningful.

Thank You!, please give me few days to build this, i will show You the result