Can I use a 2.4 camera?

[iflymyhelishigh]

Hi guys. I am looking to buy a wireless camera to use for one of my helis. If I use a DX7, will I be able to still use the camera? The camera link is here

http://www.geeks.com/details.asp?InvtId=MINI-WIRELESS-CAM&cm_mmc=GoogleProducts-_-VideoCameras&WebCams-_-SurveillanceCameras-_-MINI-WIRELESS-CAM&zmam=2003677&zmas=1&zmac=129&zmap=MINI-WIRELESS-CAM

I read somewhere that you can not use a 2.4 Ghz camera with a 2.4 ghz remote.

[Spidious]

NO

Most helicopter site even tell you to not use them with a 2.4 set up..

[jeffk]

The reason you shouldn't is because the camera's transmitter, in such close proximity to the receiver, will de-sensitize the receiver. The result will be that once the heli gets more than a few dozen yards away from you, the receiver will not be able to hear the transmitter's signals well and you will get glitching and possibly lose control.

Think of it this way... Think of your ears as the receiver, an iPod as the camera's video transmitter, and your wife / girlfriend as your controller. With the iPod off, you can hear your wife's commands fine. Turn the iPod on, and you will have a much harder time hearing her. Thus, you will be more likely to misinterpret her commands, and this will end badly.

[atomicplatypus]

Think of it this way... Think of your ears as the receiver, an iPod as the camera's video transmitter, and your wife / girlfriend as your controller. With the iPod off, you can hear your wife's commands fine. Turn the iPod on, and you will have a much harder time hearing her. Thus, you will be more likely to misinterpret her commands, and this will end badly.

Great analogy! :)

[helicraze]

Never heard of the above. Thats why we have different channels.

You need to turn on the camera first (it may have set channel) then turn on the DX7 as it will search for a clear channel.

[jeffk]

Which channels the spektrum is using is irrelevant. The channel, or frequency is secondary to the level of RF energy entering the receiver. The 2.4 GHz radio and the 2.4 GHz camera transmitter are both operating on the same frequency BAND. In order to be able to "hear" all 80 frequencies in its range, the Spektrum receiver must, by design, be what we refer to as "wide-banded". This basically means that the receiver can make use of any frequency of the 80 the trnansmitter can transmit.

Since the 2.4 GHz camera transmitter is also on the 2.4 GHz band, it emits RF energy close enough in frequency that the aircraft's receiver is sensitive to it. The receiver will be able to retain a lock on the transmitter while the aicraft is in close, but the farther away it gets, the fainter the signal will be. The transmitter for the camera will be putting out a continuous level of radio frequency energy and eventually, it will be sufficiently stronger than the signal received from the controller, and will cause glitching.

As I stated earlier, it's called desensitization.

Yes, really. :) Go here to learn more:

http://www.radioing.com/eengineer/rfi.html

[helicraze]

Well we better not use a microwave or mobile or cordless phone or wireless networking in the close proximity either.

I have heard of heaps of people using 2.4G other gear on there helis

[jeffk]

If you strapped a cordless phone or a microwave to your heli it would do the same thing. I keep trying to explain that it's not frequency that's the big issue. It's the relative signal strengths of the two transmitting devices and their proximity to the receiver that causes problems.

I've got 802.11g wireless in my home. My wireless router is at one end of the house. I have two computers. One is in the same room with the router, and one is at the opposite end of the house in my dining room, but still has a straight line-of-sight shot to the router.

In between the dining room computer and the router is a microwave that runs at 2.4GHz. It is not faulty, and I've tested it to make sure it is within it's acceptable emissions limits. In fact, it leaks very little energy. BUT. When the microwave is on, the computer in the dining room cannot connect to the wireless network. The computer in the room with the router can.

You may have many friends running that setup and it may be working for them, but it's not a good idea and I've "heard of heaps of people" having trouble and thinking twice about it after trying it. Myself included. I also happen to know a little tiny bit about RF behavior and frequency interference.

Here's another analogy: You're strapping a loudspeaker (the camera TX) next to a microphone (the aircraft's RX) and trying to use that microphone to listen to a whisper (The controller) across a crowded room. It's gonna be hard for the mic to pick up anything intelligible. It doesn't matter what sound is coming out of the speaker, the sheer noise of that sound in such close proximity to the mike is going to drown out what you're trying to hear.

[vetterick]

I tried to use one with a DX6, when I turned on the 6000 the picture got a litle wierd, then as soon as I got 5' away from the heli the servos started twitching badly, I wouldn't recomend trying.

[Madani]

jeffk is quite right. He is trying to explain the science of the radio wave behavior along with the design concepts of receivers. When you have an RX with a sensitivity of around -120dB as your aircrafts receiver, a 100mW 2.4 GHz transmitter in the close proximity will blind the receiver. In this case the "Selectivity" of the receiver will not be a helping factor. As with other phenomenon in the world of physics and electronics, there might be occasions that some arrangement or setup work in a different way. However those occasions are conditional and/or setup dependent and can not be used as a rule.
Mark.

[jstiltner]

Beyond what jeffk said, which I agree with completely is you will probably get better service from a 900mhz camera down link or even lower frequency. The reason being the lower the frequency the less shadowing and attenuation you are likely to get from heli parts in the propagation path or trees, vehicles, etc.

[seanh]

Yes you can use the camera with 2.4 gig, at worst the radio will interfere with the video and you won't have a completely clear image. This is much like the when you watch TV (regular non cable service) and turn on a hair dryer or vaccume cleaner...you get lines on the image.


Of course you could always sheild the camra.

[Flyhighusa]

Think of it this way... Think of your ears as the receiver, an iPod as the camera's video transmitter, and your wife / girlfriend as your controller. With the iPod off, you can hear your wife's commands fine. Turn the iPod on, and you will have a much harder time hearing her. Thus, you will be more likely to misinterpret her commands, and this will end badly.

I'm sorry, but I almost peed my pants a little when I read this. Awesome!