Why FPV 5.8!?

[andersonpaac]

Throughout the forum, there are several threads on fpv but the common denominator seems to be that they all run 5.8 Ghz. Through some research, I've read that the lower the frequency the better the penetration and thereby range but the bigger the antenna. Lower frequencies are also less subject to interference. Is there a reason why we don't do so? Is there someone who's running 900 Mhz or 1.2 Ghz fpv setup?
Please advise

 

[noiseboy72]

5.8GHz is usable around the world, uses fairly small antennae and does not interfere with r/c or GPS.

1.2Ghz is very close to GPS and could also produce harmonic multiples that can affect 2.4Ghz r/c.

900MHz has limited availability and requires quite large antennae.

5.8Ghz also allows for more operational frequencies.

I have run camera links on 1.2GHz without issue, but not with a GPS equipped and frankly, dependent aircraft.

 

[andersonpaac]

5.8GHz is usable around the world, uses fairly small antennae and does not interfere with r/c or GPS.

1.2Ghz is very close to GPS and could also produce harmonic multiples that can affect 2.4Ghz r/c.

900MHz has limited availability and requires quite large antennae.

5.8Ghz also allows for more operational frequencies.

I have run camera links on 1.2GHz without issue, but not with a GPS equipped and frankly, dependent aircraft.

Thanks for sharing your thoughts

 

[Elwood58]

Vision + runs FPV on 2.4 and RC on 5.8. There are some 900 mHz FPV systems.

 

[noiseboy72]

The Vision was forced to used 2.4GHz for the FPV, as it uses wifi, and there were not very many smart phones with 5.8GHz wifi at the time of design. If they were designing it now, maybe they would have used 5.8GHz for the fpv, but then again, you are not allowed a lot of power on that band.

It depends where in the world you are, as different radio laws apply. In the UK, you are pretty much limited to 5.8GHz if you have a 2.4GHz r/c - due to airborne restrictions, but some other countries allow different bands to be used, subject to licencing.

 

[golgotha]

On my Phantom 2, I tried using a 1.3GHz video tx but it made my 2.4GHz control link very unstable. I wasn't even 50 meters out before my Phantom went into RTH. I even tried using a notch filter but it didn't make much difference.

If it's penetration you're after, you are correct to ditch 5.8GHz for video in favor of 1.3Ghz, but then you'll also want to switch frequencies for your control link. I now operate 433MHz for my control link and 1.3GHz (400mW) for video tx. I have zero issues with harmonics affecting my GPS link and often do long range flying with plenty of buildings and trees between me and the aircraft. If you're wanting to make this many modifications, I recommend using a platform other than the Phantom.

 

[andersonpaac]

On my Phantom 2, I tried using a 1.3GHz video tx but it made my 2.4GHz control link very unstable. I wasn't even 50 meters out before my Phantom went into RTH. I even tried using a notch filter but it didn't make much difference.

If it's penetration you're after, you are correct to ditch 5.8GHz for video in favor of 1.3Ghz, but then you'll also want to switch frequencies for your control link. I now operate 433MHz for my control link and 1.3GHz (400mW) for video tx. I have zero issues with harmonics affecting my GPS link and often do long range flying with plenty of buildings and trees between me and the aircraft. If you're wanting to make this many modifications, I recommend using a platform other than the Phantom.

Wow , can you show us a picture of your setup. What range do you get on vtx and control?