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m0nk3hjam

Antennas - how far apart?

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I have a esky Belt cp v2 2.4ghz heli. I mounted an 800mw 1.2ghz video camera and transmitter to it. If i run the camera transmitter the range of my heli goes down to 10 metre!?! Without it it goes hundreds of meters. Im a newbie, can anyone help pretty please.

By the way, i get no video interferance at all.

oh yeah also i have ordered a 2.4ghz video transmitter reciever which will arrive at the end of the month, might that solve all my woes?

thanks in advance.

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Can you post a pic of your setup?

Is the video TX running from its own battery?

Terry

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Hi thanks for replying.

Heres some pics, I basically got everything and simply stuck it on where it fitted at the time, no real thought went into it.

to answer your question I fitted a small 2cell 7.4v lipo to the bottom of the heli to power the video system which is rated at 9v, basically i didnt want to attach a 9v battery or use the 3cell lipo that runs the heli for fear of over powering it.

as i say im a complete newbie to fpv but im eager to learn. Any comments on 2.4ghz video would be appreciated too.

thanks in advance.

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800mw may be swamping your RX. 1.2 + 1.2ghz = 2.4ghz. Thats the second harmonic of your vid Tx...

Edited by W3FJW-Ron

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You need to:

- Physically place the video TX and its antenna as far from the R/C RX and its antenna as you can.

- Set a channel on the TX which when multiplied by 2 is as far as possible from the 2.40-2.485GHz range, usually channel 4 is close to 1.3GHz, which fits well.

- Use as low video power as possible, 800mW is a lot when you can't guarantee physical separation.

You won't be able to use your 2.4GHz video TX, or it will be many times worse. What happens here is that your R/C RX gets "screamed in the antenna" by the nearby video TX, because every transmitter sends spurious emissions at all multiples of its operating frequency (harmonics), They're orders of magnitudes weaker than the desired output, but not negligible when the base power is so high and the distance that close. With your 2.4GHz TX, it would be the same, except that as it's the main output and not a "stray" one it's a lot more powerful :)

What's the brand of your R/C?

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It seems from the picture that your video aerial is flat along the bottom of your heli. This needs to be vertical to get the best range from both the video TX and the RC.

It also should be at least a few inches from any wiring or other equipment including batteries,the signal radiates from the sides of the aerial so needs a clear veiw out from the heli, not very easy to do I know but its worth finding a way to do it.

It can also help to change the type of aerial but I would try the one you have to start with.

Terry

Edited by Terry

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hey thanks for all these things to try,

couple of questions first, I cant set anything by channel as far as i can tell, I only have tuning knob on the Rx and on the transmitter theres a small screw, is that for tuning2? I did try fiddling with it but only made tuning it in harder.

secondly in the UK trhe 1.2ghz video requires a license which is why i wanted the 2.4 ghz system, will this really not work? if so what other alternatives are out there, seems to me i may be throwing my money out the window on my present course.

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OK. Seems you really got about the lowest possible grade of video TX/RX. Indeed no channel selection, and seeing as your RX has a tuning knob the frequency most likely isn't very stable. I doubt you'll get any luck with that, but still try the advice that applies in your case... we never know.

No, no solution with 2.4GHz video and R/C.

Those of us who use 2.4GHz video still use the good old 35MHz R/Cs (or whatever the "standard" R/C frequency is in your country), or specialised 433/868MHz links.

Apart from the 2.4GHz band for video, you have 5.8GHz, up to 25mW. But expect rather short ranges.

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Yeah the reason i bought the 1.2ghz video system was because of its cheapness, spur of the moment buy. I then ordered the 2.4ghz system as i thought it would be a, more legal & b, easyier to boost in a coutry where the 2.4ghz range is common. Anyway its good to know about the 2.4ghz video issues, I am planning to get my self a plane eventually and perhaps ill get that in the traditional radio frequency (think its 35mhz here) and run the 2.4ghz video ive ordered with that. What sort of range is possible on the traditional Rc frequencies by the way and are they easy to boost.

Right now I am going to move around the transmitter etc on the heli and ill post any significant findings on here later.

thanks for all your help, but please, keep it coming as its only your collective wisdom thats stopsing me from regressing back to my more primative self :)

*edit

Its an ESKY Belt Cp V2 with stock transmitter reciever

well ive tryed moving the Video Tx away from the heli Rx & away from as much wiring as possible but little to know change in the range, guess im a little stuck for the time being. heh!

Edited by m0nk3hjam

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sorry yet another silly question.

If I got a 35mhz 6ch heli Tx & Rx would i have any issues for eg. interference, digital servos not compatible etc, or would it just swap in, proper job??

thankis again.

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Ok after some unsuccessful small scale testing yesterday moving the antennas i kind of gave up but this afternoon i thought I would try again. the Pics show my results, quite why i didnt move it just a little further apart yesterday I simply dont know.

So my new question is......

How easy is it to extend the Heli Rx Antenna to the tail?

All thoughts welcome.

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Edited by m0nk3hjam

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