I want to start a discussion about FPV modules, frequencies and antennas.
Are there a FPV transmitter/receiver modules that You especially recommend?
What frequencies do You suggest? (1.2GHz, 2.4GHz, 5.8GHz -> personally I did not meet any video modules operating on another frequencies, did You?)
Are those stories about interfacing between 1.2GHz video-link and 2.4GHz RC link true? What about 433MHz?
And finally what antennas do You recommend? Are those circularly-polarized ones really making a difference?
Unfortunately I am not very experienced in this topic. I have seen some things but still not much, and I would like to know the practical side of this optimisation task.
Any response, or link to another topic would do>
As a general advice, the lower the frequency the longer the range and less problems related to interference. Thats why regular controllers are 2.4g and UHF are 433mhz for long range.
Regarding antennas CP really do make a difference. The rubber ducky ones are next to useless. My understanding about these different geometries is about shape. A wider shape has more area to receive the waves than a simple pole. The advantage of a CP is the wiring is 3 dimensional so it works well regardless of orientation. Other flat shapes like patches or yagas work best when pointing straight at the source. If you ever fly with one you will see a difference in the video quality just by rotating the "flat" antenna. When it gets side on and the tx is far away you will notice quality worsening. When its flat and pointing at the tx things improve. This is why there are antenna trackers.
Hey Mateusz Zarudzki,
The lower the frequency better penetration to objects will have. So if you are planning to fly in an area where you don't have many obstacles and is mostly open, then the popular 5.8 Ghz frequency will be more than enough, but if you are planning to fly FPV racing through an abandoned building or warehouse and you will go through rooms and walls, the 1.2 Ghz radio would be more suitable.
The interference situation it's always possible but very unlikely.
To learn more about the circular polarized antennas and other FPV equipment I will suggest you to read this post:
It explains in detail the different components of the FPV system and how to understand the technical stuff.
I hope it could be useful for you.