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Old Jan 13, 2012, 04:48 AM
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Quote:
Originally Posted by RENATOA View Post
No, isn't this what I meant
But to get a good receiver and antenna in 1.3G seems much harder than in 5.8G.
In 1.3G, from any source and vendor literaly you don't know what you buy ! I tested 6 (six) 1.2-1.3G receivers to be able to fly more than 2km with stock antennas with only one...
Still seems a false premise since you're not going to get clean video for
2km with the 5.8Ghz stock antennas ever.
It's widely known that nobody uses stock antennas on both ends of the link
on 900Mhz or 1.2Ghz.
Dunno how you went through 6 different Rxs. We know that the cheap
12-16ch ones generally all suck. They have no decent input filtering so
catch noise from well outside the 1.2-1.3Ghz band. . The Comtech based ones
(from RV) and Lawmate Rxs are both well proven. I've used three different make/model/power
1.3Ghz Txs and they all work great with my Comtech based Rx. The antennas are
what matter most.

Quote:
5.8GHz is only one model and source, and simply works.
Works with appropriate antennas.
There are actually two different "standard" sets of 5.8Ghz frequencies
that are totally incompatible with each other. For instance this
http://www.hobbyking.com/hobbyking/s...dProduct=12176
is not compatible with the 5.8Ghz Rx built into Fatshark Aviator goggles.
And of course the 100mW and 600mW ImmersionRC 5.8Ghz Tx's are not compatible with that standalone HK Rx. Kind of annoying if you want more power, but
don't want to wear the Rx on your head.

5.8Ghz channel selectivity is great though, so very handy if you want to get a lot of
FPV pilots in the air. But that's because band pass filtering gets easier (sharper edges)
the higher the frequency.

Quote:
Plus, the noise floor... you can find places awful for 1.3GHz while 5.8GHz is clean everywhere, at least now, so the 90dB of receiver are indeed 90dB, and not 60-70dB, busted by noise floor...
In what location have you found 1.3Ghz to be noisy? I've yet to see it anywhere.
900Mhz and 2.4Ghz yes.. 1.3Ghz no.

Quote:
Last but the most important... is soooo sweet to use small antennas
That is nice, but not being able to fly behind your high gain Rx antenna more than 100ft,
or having your video signal blocked instantly when anyone walks in front of your
Rx antenna at pretty much any range...

What someone needs to do is market a tiny little standalone all-in-one 5.8Ghz antenna tracker (could use
cheap standard servos) to keep the required high gain antenna pointed at the plane. Given the frequency
separation, could probably build the telemetry module/GPS/video Tx all into
the same unit for the plane. Only eats one audio channel for telemetry. Build the video
Rx and tracker electronics into the same unit on the ground station. Then you've got
a truly plug and play FPV setup that'll let 8 people fly at once.

ian
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Last edited by Daemon; Jan 13, 2012 at 04:54 AM.
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