2.4 Ghz in Pattern
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2.4 Ghz in Pattern
Mark Hubbard Fri Feb 08, 2008 9:03 am
I stand under correction in thinking that I am the first pilot to use 2.4 Ghz in competition in SA, I was certainly alone at the Northwest Champs at Klerksdorp.
I hope this post will serve to allay the many fears about this system that were mentioned to me during the competition. Before committing my beloved Alliance "Helen" to Spektrum, I did over a year's research in forums all over the world, and 100s of ground tests. Have there been accidents using the new technology? Yes there have. But I can almost guarantee you that all of them were down to incorrect or misguided installation.
Firstly, & this is especially true in a digital servo equipped 2m bird, the Spektrum system draws a LOT more battery power than the 35Mhz system. If the current draw is high (with resulting lower voltage), this can cause the Spektrum system to "reboot" meaning loss of signal for at least 3 seconds whilst it powers up again. This is more than enough to cause a major accident & I'm certain explains a lot of the incidents experienced so far. I discovered this during the 100s of tests I did on a retired trainer test bed whilst on the ground.
The second major factor is the positioning of the receivers & remotes. The AR7000 & AR9000 receivers ship with remote receivers but always with a ridiculously short extension cable.
Because (as per the experts) the 2.4 wavelength is so short, it cannot "bend" around objects like engines, tuned pipes etc. This means that the signal can be momentarily interrupted, & if in that position long enough, can cause a break in link. It is therefore vital to position the receevers so that at least one of them can always "see" the transmitter.
My solutions to the above are as follows:
1) Electrical. Power your system with a 7.4v Lithium Plymer Or Lithium Ion battery running through a regulator that brings the voltage down to 5.6v. At 5.6v your servos are a lot more powerful, and even if the system is under tremendous load such as in snaps, the voltage NEVER varies from 5.6v. You can also buy regulators in 5.0, 5.2, 5.4, & 5.8v. You choose. Whatever you buy, the voltage will never drop low enough to reboot the receiver.
2) Receiver positioning. Repositioning your main receiver is difficult, & in some cases impossible. But, the hobby shops stock extensions up to 36 inches long for the remotes & I cannot stress the importance of using these. In my Nemesis I have a remote all the way in the tail, far away from any "blockages". In my Alliance I have one just behind the cockpit, & another one in the tail. In both cases, my main receiver is in the same place as the old 35Mhz ones.
After more than 60 flights using a data logger, I found that I had a few signal fades on the main receivers (due to their positioning close to engine & tuned pipe etc), but absolutely clean & clear reception from the remotes due to them being positioned so far away. Never, during any of those flights did the system voltage vary from exactly 5.6v. Nor have I experienced one glitch.
If anyone needs further information on installing this system, please feel free to contact me.
I hope this post will serve to allay the many fears about this system that were mentioned to me during the competition. Before committing my beloved Alliance "Helen" to Spektrum, I did over a year's research in forums all over the world, and 100s of ground tests. Have there been accidents using the new technology? Yes there have. But I can almost guarantee you that all of them were down to incorrect or misguided installation.
Firstly, & this is especially true in a digital servo equipped 2m bird, the Spektrum system draws a LOT more battery power than the 35Mhz system. If the current draw is high (with resulting lower voltage), this can cause the Spektrum system to "reboot" meaning loss of signal for at least 3 seconds whilst it powers up again. This is more than enough to cause a major accident & I'm certain explains a lot of the incidents experienced so far. I discovered this during the 100s of tests I did on a retired trainer test bed whilst on the ground.
The second major factor is the positioning of the receivers & remotes. The AR7000 & AR9000 receivers ship with remote receivers but always with a ridiculously short extension cable.
Because (as per the experts) the 2.4 wavelength is so short, it cannot "bend" around objects like engines, tuned pipes etc. This means that the signal can be momentarily interrupted, & if in that position long enough, can cause a break in link. It is therefore vital to position the receevers so that at least one of them can always "see" the transmitter.
My solutions to the above are as follows:
1) Electrical. Power your system with a 7.4v Lithium Plymer Or Lithium Ion battery running through a regulator that brings the voltage down to 5.6v. At 5.6v your servos are a lot more powerful, and even if the system is under tremendous load such as in snaps, the voltage NEVER varies from 5.6v. You can also buy regulators in 5.0, 5.2, 5.4, & 5.8v. You choose. Whatever you buy, the voltage will never drop low enough to reboot the receiver.
2) Receiver positioning. Repositioning your main receiver is difficult, & in some cases impossible. But, the hobby shops stock extensions up to 36 inches long for the remotes & I cannot stress the importance of using these. In my Nemesis I have a remote all the way in the tail, far away from any "blockages". In my Alliance I have one just behind the cockpit, & another one in the tail. In both cases, my main receiver is in the same place as the old 35Mhz ones.
After more than 60 flights using a data logger, I found that I had a few signal fades on the main receivers (due to their positioning close to engine & tuned pipe etc), but absolutely clean & clear reception from the remotes due to them being positioned so far away. Never, during any of those flights did the system voltage vary from exactly 5.6v. Nor have I experienced one glitch.
If anyone needs further information on installing this system, please feel free to contact me.
Mark Hubbard- Posts : 1
Join date : 2008-02-08
jnp- Posts : 3
Join date : 2008-02-08
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