I'm going to try to write about 5.8GHz antenna choices without clouding things with too much technical jargon. 5.8 GHz is the most popular FPV transmission frequency as it's legal in most countries, including the UK. Also, 5.8 video signals are very clean and clear so long as they're uninterrupted. The downsides to 5.8GHz are that the signal is easily blocked by buildings, towers and even trees so you need a clear line of sight all the time between receiver and transmitter, plus the signal does not travel as far without degrading as lower frequencies. In general, the lower the frequency the farther the signal travels without degrading. However, lower frequencies send less information over the same distance as higher frequencies, which is why 5.8GHz gives you a better image over, say, 2.4GHz over the same distance - though 2.4GHz video transmission is still pretty good. However, we usually use radios for controlling our planes etc that utilize 2.4GHz, so it makes sense to have our video on a different frequency so they don't interfere with each other. 2.4 and 5.8 work well together. You can increase the distance of good quality video transmission by increasing the power of the transmitter and/or receiver. In fact there are a lot of 5.8 transmitters on the market with higher and higher power ratings. In some countries, UK included, you're said to need a special radio license (HAM in UK) to use 5.8 over a certain power, but the rules on this are a little cloudy where some argue it's the radio on the ground that matters more than the video transmitter on the plane. Anyway, I'm not going to delve into this topic here. The good news about using 5.8GHz is there are a lot of antenna choices these days that help increase the distance you can fly and still receive a clear video signal, even with low power transmitters. Rubber Ducky/Dipole Antennas: Rubber Ducky antennas are made with a dipole inside and are the bog standard antennas that usually ship with FPV equipment. The distance you can fly and still receive a good signal is very disappointing for most. For example if you buy the Fat Shark goggles with built in 5.8 receiver and the supplied transmitter and Rubber Ducky antennas on both ends you'll be lucky to traverse the length of a football field without losing signal entirely. This is because the so called omni-directional signal is susceptible to reflecting off objects and because the shape of the signal transmitted is not very good for using on a moving, flying object. The signal is basically the shape of a ring doughnut, so if you imagine the antenna pointing straight up in the centre of the hole the signal radiates out in the shape of the doughnut and has a hole in the middle directly overhead and below, and as your plane banks the orientation of the antenna changes so the doughnut shape is also at an angle – so instead of radiating out equally in all directions it may be radiating up towards the sky and down towards the ground if you’re flying at 90 degrees to the ground. If you get a ring doughnut and pretend to fly it round the room in your hand like a toy plane you can see how the signal will move on your actual rc plane. All the while your antenna on the ground is stationary and trying to intercept this ever tilting signal from your plane. You can alleviate some of these problems by using a diversity receiver with two antennas, having one pointing straight up and one horizontal, but basically, for FPV, Rubber Duckies are pretty rubbish. If you are using a Rubber Ducky it is best to have it mounted vertical on your plane so the signal is radiating out evenly in all directions of the compass if you fly mostly level and not above your head. Patch Antennas Patch antennas are literally a patch or square of metal, usually in a white or black plastic casing. They are better for long distance flights in a single direction. These types of antennas fall under the category of high gain antennas. The antenna’s ability to receive or transmit in a given direction in called its gain, which is measured in decibels or dBi. The typical gain of a standard Rubber Ducky is 2 or 3 dBi, where a standard Patch Antenna might be more like 8 dBi. For every 3 dBi you round about double the effective range – so a standard patch antenna of 8 dBi will transmit/receive up to 3 or 4 times further than the Rubber Ducky. However, where the Rubber Ducky transmits outwards to all points of the compass equally in terms of power, the Patch Antenna only transmits/receives at its full gain in a forward facing direction in a beam about 90 degrees wide and tall with pretty much no signal pick-up outside those angles and a very small reception to the rear. You can increase the coverage of your receiving ground station by using more than one patch antenna – placing two side by side at an angle so their beams overlap and double up on the effective width, and/or have one facing back and one front so you get coverage behind and in front. There will still be a loss directly above. Doubling up forward facing Patch Antennas will suit those into long range FPV who often fly out straight in front of them in a relatively straight course before turning around and coming back. If you want to fly a large circle with Patch Antennas you may have difficulties as your plane flies outside the beam of one of your antennas. However, you can get around this by installing an Antenna Tracker and have your Patch Antenna mounted on a rotating gear on a tripod or box so it can follow the movements of your plane. The drawbacks of Patch Antennas are the narrow beam, and you would still be using a Rubber Ducky or maybe a Y shaped antenna on your plane with this setup and be susceptible to dropouts while banking. Yagi Antennas A typical TV aerial looking antenna, this antenna can give you an extremely long range but like the patch they are extremely directional, perhaps more so. Again you can use more than one and other equipment to enhance their effectiveness, but there will still be gaps between beams as your plane moves around where you may lose signal. Furthermore, with Patch and Yagi antennas, tracking, tripods and diversity boxes etc you’re starting to collect a rather hefty ground station and looking like some kind of university science experiment. You can fly FPV to distances of over 10 miles or so with these setups, but realistically where could you fly that far in the UK without bothering anyone and perhaps getting yourself in trouble? Circular Polarised Antennas – Omni-directional Cloverleaf and Skewplaner For me and many others, Cloverleaf antennas have become the Holy Grail of FPV since they started appearing a couple of years ago, thanks to the likes of IBCrazy and David from rcexplorer.se who began making their own antennas with bits of glue and copper wire. Thankfully, as they became more popular they began to be manufactures so we don’t have to make our own, which can be pretty tricky with 5.8GHz as they’re quite small (lower frequencies have larger antennas). There is lots of information online about the mathematics of these antennas, but I don’t want to get in to that. I prefer to simply think of them as being omni-directional in every orientation, like having a collection of your doughnut shape radiation patterns overlapping each other for almost total coverage. The unique shape of Cloverleaf and Skew Planer type antennas causes the transmission to sort of sweep up and down vertically and horizontally. They pick up your FPV signal much more reliably regardless of the orientation of your RC plane. Plus, because of their sweeping pattern they tend to work at much greater distances even at lower powers because they’re more sensitive. There are a few more designs now for these types of antenna besides Cloverleaf and Skewplaner, but the principles are similar with various shapes of copper wire at the head of the antenna. You can easily achieve a mile or so with relatively low power 5.8 GHz paired Circular Polarised Omni-directional Antennas. Helical Circular Polarised Antennas These are sort of half patch and half Cloverleaf type antennas. They are directional antennas that work very well with a narrow beam without dropouts cause by the orientation of your plane. A typical helical transmitter may have a gain of 13dBI, 6x more powerful than the Rubber Ducky. You can get away with mounting these on your FPV goggles, if you use goggles, and moving your head. However they’re probably best paired with a Cloverleaf or similar on a diversity receiver so the Cloverleaf can pick up and take over the signal close in and behind you. Diversity Receivers Diversity receivers are basically a box with a receiver inside and some extra circuitry so you can attach two or more antennas. The DR unit measures which antenna is picking up the signal more successfully, giving the strongest signal, and uses that antenna to send the video signal to your goggles or LCD screen. Some companies have made FPV screens with diversity receivers built in and two antenna inputs on top. I use one of these myself for my professional aerial photography setup on a hexacopter. For my planes flying FPV as a hobby I use Fatshark goggles with Cloverleaf/Skewplaner attached on goggles and plane. Enclosed Cloverleaf/Skewplaners Because the copper wire makeup of these antennas is quite delicate you can now buy enclosed versions with a plastic case around them. Fat Shark do enclosed versions as do Fox Tech and a few others. I use these exclusively because if you bend or distort your pretty copper wire assembly the signal deteriorates.