I Found the Secret to WiFi Antennas!

Hey Scott 😊 Really enjoyed this video!! I studied antenna theory during my master's degree, so it was really watching you test and explain antennas ahah 😊 ahhhh I really miss RF engineering!

As a very simple rule of thumb on antennas; When you have antennas that promise a gain of X dBm, then you know the antenna is more selective. In other words, there are less directions with a good reception. Just consider a theoretical point size antenna. Then you will have the same signal quality regardless of the orientation from the antenna. So on each point on a sphere you will have the same signal strength/quality. Since such a point size antenna doesn't exist, you will have some shape of the antennas you show in the video. Now back to the sphere where you can have a good reception from the antenna. Those dipole antennas will just result in a smaller band around the equator of the sphere. So when you consider the spots with good reception on the sphere, you effectively have a smaller area on the sphere with good reception. The amount this area is smaller compared to the full sphere is what you 'gained' in RF signal strength, since you send out the same RF power, but to a smaller piece of the sphere. Thus it makes the antenna more 'selective' as you can't get a good signal in some directions from the antenna. This is exactly what is meant with a 'gain' of an antenna. You keep sending the same amount of power, just to fewer directions. The antenna itself doesn't have some active components like an amplifier, so there is no amplification of the signal. It is just transmitting in fewer directions. The most well known example is a satellite dish, where the antenna is only sensitive to a very small area in the sky. Another example is a directional antenna like those cantennas made from a Pringles crisps container. Oh and about those VNA's. I don't know the one shown in the video. (which does look a lot like the LiteVNA/NanoVNA) However from another brand/model like the LiteVNA/NanoVNA, there are a lot of clones sold on sites like AliExpress. So best to buy those from an official reseller or else you may not know what you're buying. And as we say in Dutch: "Meten is weten als je weet wat je meet" (Measuring is knowing if you know what you're measuring)

Man, this channel is a super useful sub. Great analysis of something that's baffled me forever.

Ah the mysterious world of Electromagnet Resonance! One of my favorite rabbit holes. I have a router that I was given that the guy who gave it to me had lost the antennas. I built a set. Cutting and tunning them was more fun than using the router. I love playing here in mysterious world of Electromagnet Resonance! Peace

I am musician and electronic engineer. The analogy of the tunining fork was genious! If someone has explained that to me like this it would be much easier! Nice one Scott!

Looking forward to the Yagi followup!

Vee antenna are easy to make and in my experience work very well. I use them for long distance UAV drone flights.

Great video. On your next class/video it would be cool if you showed how a Smith Chart works and how you can calculate the matching network for an antenna and demonstrate how the component values do actually correlate to what you calculate they will do on the Smith Chart (as displayed on the VNA).

Enhorabuena, buen vídeo. Es claro e instructivo. Aunque has tocado tangencialmente la adaptación de impedancias, sería bueno explicar que ese tema está relacionado con el coeficiente de onda estacionaria y es importante minimizarla (no solo para mejorar el rendimiento maximizando la señal emitida sobre la reflejada, sino para evitar quemar el circuito emisor con el retorno de la misma). Además, es interesante comentar que influyen parámetros como el volumen del elipsoide no obstaculizado (zona de Fresnel) y también, tan importante o más importante que el patrón de radiación que has explicado adecuadamente: la polarización de las antenas. ¡Un saludo! Tienes un nuevo suscriptor 😊

Great video, we would like more videos about antennas :)

Excelent video. I would love to see more videos of this topic!!

An embedded mobile device engineer once told me: it's not just about putting a bigger antenna to it. You will raise input sensibility in a certain sense, but as long as the output power stays the same, you will have to take other things into consideration (like dampening, resonance, energy etc etc)...

The antenna radiation pattern does have an effect on the power coupling but not quite in the way you described. Even if you tipped one antenna sideways 90 degrees (eg to the left), the receive antenna would still be in the same radiation lobe you drew at 5:43. However the polarization of the electric and magnetic fields is now 90 degress off, so the receiving antenna element cannot be excited and the received power would be much lower than if they were both pointing vertically. If you pointed the transmitting monopole antenna directly at the receiving antenna, it would then be in the low point of the radiation field pattern, and the recieved power would be significantly reduced because of both polarization mismatch and lower field strength (out of the main radiation lobe).

Very helpful video! Made some immediate adjustments to an antenna attached to a BT proxy. Thank you!

I tried building one like 12 years ago.. and I managed a verry nice distance by using a Yagi type antena and a small parabolic "dish" that was a lid from a cookware covered in aluminum foil as a reflector. (The antena looked similar yo yours - the big one from the thumbnail). The second design was actually another antena made from a long screw with the elements being metal discs fixed with nuts on the screen and the reflectior being a tin can, when we mounted this on a 60cm parabolic dish (where the LNB sits) we got 160km wifi range(Valencia to ibiza), barely usable(50kbps)

Years ago back in the 70's we had a CB radio and could make our own areal using a coaxil cable with the single wire vertical and the brad wire horzional like a L shape i know it was on the 27mhz but it did work and had to be the same length, but i dont thinkg this will help you, very intresting video thanks for sharing

As a radio amateur, I still find antennas a dark art... but they are fun to play around and experiment with. The satisfaction of building your own antenna that works :) The Nano VNA is a must-have tool.

The best time for DIY Antennas on wifi was 10-20 years ago. Nowadays routers use MIMO, that means multiple data streams via multiple antennas. Some routers even use phased arrays, which is more HF black magic and can create movable directional beams without moving parts. Even for outdoor or P2P links there are ready made project nowadays. I run a tp-link cpe210 for 2.4 Ghz and a ubiquity nanobeam for 5 ghz. These receivers are integrated into dish/plate antennas, work out of the box and you can get them (or the china clones) for cheap.

when I was a Kid, my Dad also tryed to build an own Antenna. His Version was made out of the plastic rod from the Package of blank CDs for mounting, a wire shaped like a diamond based 8 and a CD as Reflector.

Very nice, the world of RF is truly amazing.