We often get asked which radio/transmitter to buy from new folks getting into RC and UAVs. The answer however is not a simple one and in many respects is like FORD vs GM or PC vs Mac. A lot comes down to personal preferences in regards to brands, look, feel, and price. That said here is some guidance…
The radio is a core piece of your equipment, one you will use across multiple aircraft and for years to come. You want to make it a long term investment, not end up having to replace your radio when you run out of channels or features needed for new aircraft. Prices can range from as little as $25 through to $1000+ for higher end radios. There are lots of bells and whistles available as well from simple flight timers through to color screens and voice feedback, as well as telemetry systems that provide real time status of voltage and other parameters from the aircraft. If your not sure if you’ll be in the hobby/industry long then a used or cheaper 6 channel radio might be the best starting point, otherwise purchase as much as your budget allows to future proof yourself as much as possible, something you feel will last you 3 to 5 years until there are major advancements in technology which is always bound to come over time.
Don’t scrimp on channels. Each channel allows one individual function on the aircraft to be controlled. Most UAVs require at least 4 channels or more, often 6+ for core features. (pitch/yaw/roll/throttle, flight mode, advanced IOC flight modes, return to home, retracts, etc). The minimum we suggest is 6 but ideally 8. When adding in a camera and gimbal to the mix this can quickly grow further (shutter, pan, tilt, roll, gimbal mode, etc). For a single operator setup with camera you would want a minimum of 8 channels for the core functions, and ideally 12+.
For multi operator setups, such as when you want a secondary dedicated camera operator in addition to the pilot, you will need a secondary radio and receiver. This reduces the channel requirement for a single system, so you can use two 6 or 8 channel radios to handle all the functionality between both. Most 2.4GHz radio systems will work fine with each other operating at the same time on a single aircraft so this is not a concern (as it once was with older FM based radios that did not have automatic channel selection and hoping).
The big name brands and most popular with local RC clubs/users and carried by hobby shops are Spektrum, JR, and Futaba. To a lesser extent also Hitec and Graupner. There are also the various Chinese brands from HobbyKing and others.
Spektrum makes a wide range of radios, from cheaper 6 channel through higher end 18 channel. The DX6 would be the lowest end suggested due to the limited channels. If budget allows the DX9 or DX18 are great choices. Spektrum is carried by most local and online hobby shops so sourcing them is fairly simple. Also they are one of the most used brands so finding help is fairly easy due to the large user base. Currently we use a DX9 for flight control and DX8 for gimbal control.
Futaba is also a popular well used brand and again carried by many hobby shops. The 8FG (discontinued) and 14SG are both great radios for UAV use. One nice advantage of the most Futaba systems is the use of SBUS. This is a receiver interface technology that allows a single cable to use used to connect between the radio receiver and many flight controllers, making the installation cleaner and easier.
We have found that the Spektrum radios are generally a bit more user friendly for new users over Futaba, but can lack some of the programmability/flexibility in setup that the Futaba provides.
Right now one of the the more popular and probably best bang for the buck in terms of price vs features is the FrSky Taranis X9D. It offers an open source based software system to allow for endless customization and at a price point well below the name brands, running around $200-$300 depending on the bundled items. The biggest item of note with the Taranis might be the learning curve as it is a bit more involved to setup and configure, however there is becoming a wealth of online videos and tutorials for the radio as it’s usage grows.
It is worth checking with RC local users and clubs for used systems as well. Those into the hobby or commercially are often upgrading gear, so there may be opportunity to pickup a used radio sufficient for your needs to start.
Most of the newer computer radios support storing multiple aircraft/models within their memory. This allows you to have multiple aircraft setup for use from a single radio. Some of the cheaper radios may not provide this and are setup to a single aircraft, or you need to manually reconfigure whenever you change to fly a different craft. With the current availability of multi-model computer radios it makes little sense to invest in a single model basic radio in our opinion. They also give more functionality in terms of other customization and settings.
Most all standard RC air radios these days work on the 2.4GHz band, using different flavors of frequency hoping and spread spectrum technology. One thing to keep in mind is that radios are not compatible across brands, they are each designed to work only with their own matching receivers (or 3rd party compatible versions). You will need a matching receiver for each aircraft, so keep in mind the cost of receivers when purchasing your radio as you will need to purchase more over time, although there are some 3rd party or “clone” receivers now on the market such and the OrangeRx and Lemon Rx receivers for Spektrum that can be a cheaper alternative. For larger and higher cost aircraft we do suggest sticking with brand name receivers however.
2.4GHz is usually sufficient for 1KM of range, fine for most multicopter UAV use. For longer range control, typically for fixed wing UAVs, you will need to use a UHF based system, such as DragonLink, ImmersionRC EZUHF, or others. These typically connect to a standard RC radio via the trainer port, or module based if the radio supports them. You may need to keep in mind that most UHF systems also require a HAM amateur radio license to be used legally in many countries, and also cannot be used commercially in most cases.
Radios come in a couple different stick configurations that you need to be aware of – Mode I (1) and Mode II (2). The following article from Spektrum explains the difference:
The Mode II configuration is very similar to the layout in a full-size airplane. The “stick” controls the Aileron and Elevator functions. Rudder is controlled by the “rudder pedals” and the Throttle is controlled with the pilot’s left hand on the side of the cockpit. A Mode II RC transmitter controls the aileron (roll) and elevator (pitch) with the right hand, while the rudder (yaw) and throttle are controlled by the pilot’s left hand.
Mode I moves the throttle function to the right stick and the elevator control to the left stick. This separates the primary controls so that there is less accidental “mix” when moving one control or the other, as is common with Mode II. The Mode I pilot will be controlling the throttle and aileron with his right hand. The rudder and elevator will be controlled by the left hand.
In North America Mode II (2) is generally the standard used. There are also Mode 3 and 4 variations but they are far less common. If you are buying from overseas be sure to purchase the proper mode.
If possible, try out a radio before you buy, see if the shape and switch position fits your hands comfortably. You want the radio to become an extension of yourself, so being comfortable to hold and use is key. Ask other users in your are what they use and what they like and dislike about their radio. You can also check online forums such as RCGroups to see what others are saying about different radios, issues, and reviews.
There is no “best” radio,it all comes down to selecting a radio that works for you and you are comfortable with and fits your budget. They all have pros and cons and feature that may or may not be suited to your specific needs.