hi guys... im new to the group... im looking to design my own antenna's and hopefully resell a few as i have loads of 3d printers. ive also just started my website where i will be selling my 3d printer mods and drone mods+ anything else i can sell... gotta try anything after the covid lul ive been in... im not too keen on stealing peoples designs directly for sale (dont mind if i redesign something from scratch that does the same job - thats fair game)... its obviously looking like the physical layout of these antennas is gonna be the same for my design as whats already out there...
anyway to cut a long story.... anyone seen this mashup of the yagi + parabolic? ... anyone in the know maybe tested these? would a parabolic work better or worse on the back of a yagi or is it just gonna be over kill... thought id post it anyway as i havent seen anyone else mention this design and i thought it was interesting...
A combination of both types of antennas boosters, yagi and parabolic. The last element (reflector) could also be much bigger. Its for Mavic Mini CE version (Europe), so I focused on 2.4 Ghz, which gives by default the maximum distance. I will be happy if someone tests it and write the results...
www.thingiverse.com
Welcome to the group ...
A Parabolic dish works by focusing RF energy back to a point where you locate an antenna element (dipole). Due to the focussing, the received energy is much higher than if the dipole was sitting in space by itself. In the same regard, the transmitted energy from the dipole is reflected in a single direction - like a flashlight focuses a light beam in one direction.
In contrast, a Yagi antenna is an extension of a 'transmission line' and uses the distance between the transmission elements to build 'standing waves' that add in the forward direction but cancel each other out everywhere else. The Yagi has a set of elements consisting of a dipole, with a reflector bar behind it, and director bar in front.
Although the results are similar, the two technologies are working in entirely different and unrelated ways.
The 'steeod' item you posted above, seems to be using the parabolic part as an extension to the reflector bar. It's parabolic in the horizontal plane but is not a dish. The mistake here is the designer has taken the name of the 'reflector' element in the Yagi literally. The reflector element is not there to 'mirror' RF energy back onto the dipole. The way it works is that the RF energy passing it induces Electro-Magnetic energy into the bar. That causes the reflector bar to 're-emit' the same signal. Due to its position and length in relation to the dipole element, it adds to [amplifies] the RF signal arriving at the dipole (or being Transmitted by the dipole) - as long as that received signal is coming from a point in the same plane as the dipole and the reflector - and the dipole and reflector are perpendicular to the source of transmission - and the transmission source dipole is the same polarity (vertical in the case of a DJI Mavic) as the Yagi's elements.
In the real-world, the choice of 'Parabolic' or 'Yagi' antenna comes down to the frequency of the RF service you are carrying. Yagi's serve the lower frequency ranges, while Parabolics are used up in the microwave end of the spectrum, where you no longer use a dipole antenna but focus the energy into a Wave-Guide.
It's a long time since I did my antenna theory as a Civil Aviation Engineer, but I can tell you that if putting a parabolic reflector on a Yagi antenna made an appreciable difference, you would see them everywhere!
In regard to 'stealing' designs - I'm afraid that there is ONLY one design for a Yagi, and even if you did all the physics to design it from scratch - unless you got the Math's wrong - it would look exactly the same as what's out there right now. You may as well buy a product that customer feedback says it works - and base your design on that!