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        Discussion 2.4ghz hard deck ?

#1 Coyote64 Jun 09, 2010 02:41 PM

2.4ghz hard deck ?
 
With my soon coming 400mhz UHF system the problem of flying at low altitude over long distances from a radio point of view are pretty sorted.

The limiting factor will be getting a reception from my video tx

Im using a 2.4ghz 500mw tx with a circular 8db patch

What sort of low altitudes will be possible at given ranges where the video will still work fine ?

#2 lovegroove Jun 09, 2010 02:57 PM

Thomas recommends 1m of altitude for every 10m from home. Unless you live in a completely flat part of the world with not trees or buildings, don't expect to be flying at 5m off the deck when you're 5km out.

#3 Daemon Jun 09, 2010 04:25 PM

I can't speak to 2.4Ghz video since I don't use it any more, but I've had solid 2.4Ghz
R/C control way way below 1:10 ratio. I actually think 1:10 is very
conservative, perhaps by as much as a factor of 5 to 10.
Thing is, 2.4Ghz is very direction, and being high frequency it does not have
a really huge fresnel zone. Also 2.4Ghz video antennas don't generally need or benefit
from being near the ground like 900Mhz and to a lesser degree 1.3Ghz do, so if you want
to fly low and far away, just elevate your Rx antenna/s.

ian

#4 Coyote64 Jun 09, 2010 04:59 PM

Right i see, most my flight will be conducted from a point 803m above sea level with my flying space in front of me dropping to sea level ( most of the time )

What sort of height am i looking at with my antenna tracker ( coming soon ) / patch setup to get most effective performance ?

#5 renatoa Jun 09, 2010 11:39 PM

Quote:

Originally Posted by Daemon (Post 15280906)
I can't speak to 2.4Ghz video since I don't use it any more, but I've had solid 2.4Ghz
R/C control way way below 1:10 ratio. I actually think 1:10 is very
conservative, perhaps by as much as a factor of 5 to 10.
Thing is, 2.4Ghz is very direction, and being high frequency it does not have
a really huge fresnel zone. Also 2.4Ghz video antennas don't generally need or benefit
from being near the ground like 900Mhz and to a lesser degree 1.3Ghz do, so if you want
to fly low and far away, just elevate your Rx antenna/s.

ian

I second this, in my recent range tests I got +5km 2.4GHz RC at ground level with an altitude difference of 40m between Tx and Rx, and direct visual between them.

#6 Coyote64 Jun 09, 2010 11:54 PM

So a lot better than i thought then i figured thn, ill start off conservative and take it steady :)


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