Firstly, there is more chance of having your video signal interfere with RC planes. Even if your own model is on a long-wire FM/PCM frequency, there may be other models flying in the area and video transmitters are one of the hardest forms of interference for any 2.4GHz RC system to contend with. Non-hopping systems like DSM2 are the most at risk.
Secondly, you run the risk of getting interference on the received video signal from a wide range of sources -- from other RC transmitters to cordless phones, microwave ovens etc. Losing your video signal when your plane is beyond visual range will almost certainly mean the loss of the model -- unless you've got a "return to launch" system such as that on the FY21AP.
That depends entirly on what power your vtx is at. Anything above 100mw and none of those will have any effect what so ever. Microwave ovens ? No not at all. The only risk you might un if flying low over housing is illegal 2.4ghz cctv units or 1.2ghz cctv units, afterall 2.4ghz is the second harmonic of 1.2ghz.
Yes you have to multiply your transmitter by 4x to achieve double the range, but far easier to increase the gain of the antenna
Trappy uses a 500mw lawmate transmitter not a 1W
Those hi-gain antennas are very directional so you would certainly want to use automated antenna tracking because if they're pointed even slightly away from the model (+/- 5 degrees) then the signal will be lost and you'll have no signal.
Lol, no not at all. A high gain antenna like a patch or a yagi has a beam width of more that 40 degrees normally. So taking 40 degrees as an example you can point it 20 degrees at least each way from the plane. Ive flown my radian 0km out and 2.3km to the right of my forward facing " directional" antenna just to disprove this theory. My directional yagi that shouldnt be able to see the plane was receiving perfect picture.
Anything that relies on a signal from the video system to orient the tracking of the video receiver antenna is (IMHO) a little bit dodgy.
If the signal is lost (for whatever reason) then how does the tracking system know how to point the antenna -- because without the signal it's searching for, it has no coordinates to use to calculate bearing and azimuth.
It is far simpler and more elegant to use the telemetry downlink on an RC system that provides this info. Remembering that if that signal can't be heard then you also can't control the model so everything becomes somewhat academic.
I use antenna tracking on my fpv planes using an EZOSD with telemetry send down the audio channel. How can it be dodgy ? The antenna is pointing directly at the plane, the video is received the audio too. If the signal gets broken up the antenna remains pointed at the plane according to last position. With is beam width at distance its that large it would take the plane minutes to fly out of the reception of the antenna. All the flights ive done it never happened once. If with any system the video is lost having telemetry is pointless anyway. You cant fly a plane you cant see.