Although I have been flying SUAS drones for several years and 107 certified, and all of that, I have been, and I am experienced in antenna Siri simply due to the fact that I have an FCC licensed “extra class“ amateur radio operator for no less than 40+ year. I am familiar with all various types of UHF, VHF, HF & LF, radio theory, radio, frequency, propagation, antenna, design, etc. However, what I do not know, at least in practicum is the best way to integrate (physically attach the coaxial cable lines” to what amounts to are the 2/twin stock antenna ports on most drone, smart controllers. (Various types of UHF connections, depending on the manufacturer).
That being stated, I currently do utilize LMR400 flex your cable on both my HF amateur radio stations and VHS/UHS transceivers. Given that all drone frequencies are either in the 2.5 GHz and 5.8 GHz frequency ranges (with exceptions of the 900 MHz frequencies in European countries.) obviously has the power that is running from the smart controller. (I have no idea how many watts are being transmitted from most manufacturers, smart controllers)
But it would be my first assessment based on the various manufacturer claims, and just understanding radio theory and antenna, propagation physics that the various manufacturers such as alien tech, and all the others are frankly a complete waste of money. Or at best and extremely poor return on investment. UHF frequencies with very rare exceptions always travel, line of sight and the higher frequencies such as 5.8 GHz cough are even more susceptible to line of sight and other natural obstructions.
Therefore, it is my hypothesis that there are only three possible ways of improving range in a reliable way. The first of which is to somehow develop a more sensitive receiving antenna on the actual drone itself. I would not ever begin to attempt this personally. However, the remaining to a question. The second way would be to increase the actual output of both the drone transmitter that transmits radio frequency, and the smart controllers, output, power. You would have to increase the water gel put a boat sense. It obviously requires bi directional communication.
Therefore, the only way to reasonably achieve more reliable ranges in any type of environment whether it be urban, natural obstructions, or other, would be to increase the height of the transmitting/receiver (transceivers/smart, controller) device. I’m not certain as to why all smart controllers require two separate antenna, other than perhaps one of the two stock antennas ask, is a “parasitic antenna“??
But all antennas require is basically a ground plane, or if not ground plane, Director and reflector, or the most basic antenna, a vertical antenna, which requires a ground plane and if not a vertical antenna than a dipole type of antenna and I have no idea if the smart controller ask is a dipole antenna because it has two separate UHF antenna on each smart controller?
So the question remains for me is that of the two antenna on all smart controllers for drones, are both antenna transmitting radio frequency or is one antenna the transmitting antenna and the other antenna a receiving antenna? Does anyone know the basic design of smart controllers, when it comes to the function of the two separate stock antenna?
If someone knew that I would be happy to work on some antenna modeling with some antenna modeling software that I have and come up with a very directional as well as an Omni directional antenna that could be placed either on a tripod 10 to 20 feet from ground or if someone has a mast or a tower that is higher than that like I do, That could be placed 85 or 90 feet above ground, indeed, with LMR400 or LMR 800DB loss would be insignificant, and the transmitting and receiving gain would be tremendous and the range improvement would be also substantial. Sorry for any grammatical or contextual errors as I used voice to text dictation for this post.