Watching my drone take off and begin to fly an autonomous mission can sometimes bring a mixture of excitement as well as a small level of apprehension. The ability to monitor the operation remotely provides critical data such as where the vehicle is, it's current status, and a whole list of information I have come to rely on.

To ensure a solid communication link, the proper antenna selection can play a large part. With the right equipment, I have found that I can maintain a quality connection with the drone and in some cases, even extend the effective controllable range.

This can be a daunting task when looking at all of the options and terminology associated with antenna design:

gain
polarization
dB
beamwidth
omni-directional
etc.

The list continues to grow along with doubt and confusion about what antenna is right for the mission. Ultimately the mission itself is what will determine the right antenna choice, but I can share some of my experience with some of the more common antenna types you might be considering.

Rubber Ducky ..... You're Not Always THE ONE

You probably already have one of these as they come standard with most drones and are typically used for lots of other common consumer equipment. The reason? These provide an omni-directional pattern. In other words, the antenna radiates signal and receives signal equally in almost all directions. Of course there are some directions relative to the antenna where the signal is poor (typically the "top" of the antenna), but for the most part, these antennas can be effective in just about any direction.

Typical "Rubber Ducky" Antenna - Image Courtesy Wikipedia

You may be thinking that if you are only communicating in one direction between you and the drone, then wouldn't this type of antenna be "wasting" its signal by sending it in all directions? In some situations you would be correct, but having an omni-directional antenna means that you don't have to concern yourself too much about where the drone is in relationship to you or the antenna, and you can fly in almost any direction around the antenna.

Of course you may only need to fly in specific directions and could benefit from taking some of that omni signal and focusing it in the direction of the drone, in which case a different antenna type may be better suited for your mission and might give you a performance edge.

Patch Antenna

A patch antenna can be quite useful in situations where you have the ability to point, at least in a general direction, the antenna toward the aircraft. These typically have a majority of their ability to send/receive signals focused in a more narrow direction, which makes them "directional".

I would typically use this type of antenna if my focus was to keep a strong signal between myself and the aircraft for a longer distance than I would typically have with the rubber ducky type of antenna. The trade-off here is that the face of patch antenna needs to be pointed in the direction of the vehicle. This is just another thing the controller/pilot has to keep in mind while flying, but there are some alternative ways to ensure pointing of the antenna automatically such as using an "Antenna Tracker".... more to come on this topic in a later post!

Stop Screwing Around!

This next type of antenna is typically called a "Helix" antenna and has a corkscrew appearance. These provide a highly concentrated signal and are very directional. These typically have a very unforgiving amount of error in where the antenna needs to be pointed, so these are most effective when used with an antenna tracker.

These are commonly used for video signals between the drone and a ground receiver because of the higher frequency of the video transmitters as well as the antenna design making the signal circularly polarized. I won't go into any of the technical details about polarization here, but the advantage for video applications is that when a polarized signal is reflected off of surfaces such as the ground or other structures, the reflected signal is polarized in the opposite direction which the receiver then ignores since it is only capable of receiving signals polarized in particular directions. This often means that video can be received clearly and without the presence of "ghosting" or other video artifacts introduced by reflected/delayed signals.

So, these were just a few of the typical antenna types you may see in use by drone operators. While these have their own advantages and uses, it is important to understand their capabilities and know when a certain type makes the most sense to use for your mission.

A great resource for learning more about antenna types and fundamentals of radio signals in general can be found HERE