How long 2.4GHz antenna should be?

Support my work https://www.patreon.com/pawelspychalski It's a common believe that the "perfect" antenna length is "wavelength by four". It is, however, not true. Or at least, not entirely true. This video explains this phenomenon and explains what the real antenna length for Express LRS or other radio should be. It kind of makes sense, after all, with a speed of light, "correct" quarter wavelength for 2.4GHz is 31.25mm. Too bad it is not true, and all those "pseudo-experts" (damn, I think I'm one of them now) tell the only small piece of truth. Equation "c/f/4" is correct but only assuming antenna is made from the void. And we all know that this is not the case. In a wire, things like dielectric constant, Velocity Factor (Propagation Factor) starts to do their things and as a result, those 31.25 for 2.4GHz antenna length is only a myth. On top of that, the 2.4GHz band does not mean this is exactly 2.4GHz. Frequency hopping adds something from itself! This video shows why and what goes where. https://en.wikipedia.org/wiki/Velocity_factor https://en.wikipedia.org/wiki/Relative_permittivity#Terminology And yes, there is a second part: https://www.youtube.com/watch?v=5bOshGLg8wg