Hi all,
I've been trying to increase my video link range on my multirotors for a while without much luck (at most a few hundred metres). But recently I got a fixed wing (Skywalker) in the air, and with exactly the same setup I can get 3.5km+ range using a helical receiver on my fatshark goggles.
There are a lot of obvious candidates as to why, but I've ruled out everything I can think of:
- The ImmersionRC 5.8ghz 600mw video tx and spiro CP aerial are the same in both setups (I've swapped them over to test)
- In both vehicles the video system is completely electronically isolated from the rest of the electronics (ESCs, radio control link, telemetry, etc).
- Both systems use all the same type of radio transmitters and receivers (Taranis+X8R for RC, 3DR 900mhz telemetry).
My theory was that it was the carbon fibre construction of the Hex that was blocking the signal, or it was the increased EMI from all those ESCs, but I tried hanging the whole vtx+aerial on longer cables well below everything blocking and at least 30cm from the ESCs+PDB+battery, still no good.
I'm at a bit of a loss: can anyone think of other reasons for the vastly increased video interference on the Hexa? Could it be from the camera or HDMI converter itself, which is still relatively close to the EMI?
Replies
PS - I get the almost the same range using Fatshark rx and immersionrc 600mW tx (550m on 5.8) and IBcrazy omnis. I upgraded to a 5 turn IBcrazy on the goggles, and got over 700m (on 5.8). This is a 4.5kg quad, running 30A ESC's and 360kV motors on 6S. It's not RF quiet...
I mounted my tx downward on the legs, so it's only 1 inch from the grass, and the antenna is as far away as possible from the noise. I fly high, so downwards is better. Mounted upwards, I only got 300m, and massive fresnel zones outages. Moving it underneath improved range and cut outages significantly.
It's still RF, in my opinion.
Completely electronically isolated? Including the source battery? BEC's can be noisy...
6x ESC's vs 1, 6x low kV motors vs 1 smaller one, 12x power cables vs 2, everything packaged into a space 1/2 the size, 4-6S volts on the quad vs 3-4S on the skywalker etc etc. 30cm is probably still not enough separation.
Only way to be sure is to use a spectrum analyser. With everything turned on, you should see a higher noise floor on your hex. A spectrum anaylser will be useful for when you plan longer flights, so is a good purchase anyway.
If you want to isolate the noisy component, try turning on 1 component after another. If you see any large jumps in the floor, you've just found your noisy component.
Are you flying the plane at a significantly higher altitude which would mean there are less obstacles ? Does your hex fly much closer to the ground ?