Create an FPV-system: Part 2 - The Receiver and Monitor

Create an FPV-system: Part 2 - The Receiver and Monitor


When I started putting together an FPV-system for my Phantom 2, I thought the transmitter (see part 1) was the hard part of the set-up. I was wrong. While the transmitter only took me only a few minutes to set-up, I spent hours and hours trying to find out why my reception was so poor. Turns out I hadn't read up on the intricacies of radio reception and the huge role antennas play in getting better video reception. I'll share my findings here, to save you the hassle ;)

When looking for an FPV monitor, I went with the smallest option I could find: the Foxtech PVR58. It's convenient to have a small monitor with a built-in receiver and antenna, right? Well, I should have read up on things first. The reception with the standard antenna was abdonimable, and - adding to the situation - the screen was very low-contrast and dark. Not recommended.

Then I started researching into my problem, and found two important clues:

Antennas

Without getting too technical, each type of antenna has its own characteristics and range, so knowing the characteristics of each antenna can help you improve the reception for your particular use case. Most important takeaway will be that the standard antennas that come with your receiver will give you the least amount of range. They're commonly called "rubber duckies" and I'm not sure if there is much love in that expression ;) I'll outline some common antennas below:


Rubber Duck Antenna

The standard antenna that comes with your receiver or monitor. It does not have a long range (low dB) and the radio waves are such that pointing the antenna horizontally or vertically it can make a massive difference on your reception (vertically polarised).

Cloverleaf Antenna

Cloverleaf antennas have a much bigger reach (higher dB) and the shape of the radio waves is such that it doesn't matter if you point them horizontally or vertically, the reception will be good (circularly polarised).

Patch Antenna


If you want very long range reception, a patch antenna might be a great solution (even higher dB). The downside of this antenna is that the distance you gain, goes at the expense of the 'width' of the signal: you have to point the antenna towards your Phantom.

In most cases, replacing your standard 'rubber duck' antenna with a cloverleaf antenna will be all you need to do to greatly improve FPV reception and range. Even more so when you also attach a cloverleaf to your Phantom.

There is one important thing to keep in mind when buying an antenna: different transmitters/receivers might use either a SMA or RP-SMA connector. You need to make sure which connector you need for your transmitter or receiver. The DJI transmitter from part 1 of this tutorial has a different connector than the receiver I use. The fact that most cloverleaf antennas are sold as a pair, with the same connector type complicates things further. Anyway, double-check which connector you need before you buy an antenna.

If you want to know more about the different characteristics of antennas, I highly recommend this video from RC Model Reviews, or for a really in-depth explanation, check out this video tutorial from Joop Media which visualises the difference between linear and circular polarisation.

Diversity Receiver

A diversity receiver is a receiver that can automatically switch between two antennas, depending on which antenna has the best reception at that moment. This is a first important step in improving your FPV video reception. Another added benefit of this set-up is that you can use two different types of antennas for different situations. For example you can use a cloverleaf antenna for flying behind yourself, and have the receiver automatically switch to a patch antenna when you're flying far away.

If you're lookin for a monitor with built-in diversity receiver I can highly recommend the FlySight Black Pearl monitor. It has a 7 inch 720P screen with good contrast and brightness and the diversity receiver is nicely integrated: each antenna has its own led, so you can easily see which antenna is currently being used.

The Flysight Black Pearl FPV-monitor on my Phantom's remote control

Learning more about antennas and their characteristics, as well as getting the Black Pearl monitor has greatly improved the quality and range of my FPV-reception. If you have any questions about particular antennas or the Black Pearl, please let me know in the comments below.




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