Author Topic: 900Mhz, 1.2Ghz or 2.4Ghz?  (Read 4905 times)

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AleG

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900Mhz, 1.2Ghz or 2.4Ghz?
« on: January 08, 2010, 02:28:50 AM »
Hello there, I just signed in to this site just to look for an answer to this question, let's see if someone here knows the answer to this one because I've looked everywhere and can't shed any light on this matter.

I'm thinking about building a FPV (First Person View) model airplane, basically it's radio controlled electric plane with a camera mounted on a swivel that tracks the movements of the head of the pilot on the ground, pretty cool if I can find video goggles for a good immersive ride.
The thing is that the video transmitters and receivers come in three flavours, 900Mhz, 1.2Ghz and 2.4Ghz. Different countries have different regulations concerning the use of the radio electric spectrum and I'll be darned if I can find the Thai regulations for this. Namely, which one of those frequencies (and perhaps among those, which channels) are legal to operate in Thailand without the need of a license?
The systems I have in mind have between 200 and 500 mW of power, with a signal range from 300 to 500 meters.

Thanks a lot in advance.

Offline HS0ZFZ

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Re: 900Mhz, 1.2Ghz or 2.4Ghz?
« Reply #1 on: January 09, 2010, 10:17:28 AM »
Dear AleG,

Well 900 MHz there is no frequency allocation for such a kind service ...same thing 1.2 GHz ...

There would be only a chance to do it in the 2.4 GHz band (max. Output power 100mW). This band is also allocated for WIFI (wirelesss LAN devices - WLAN). There should be also some 2.4 GHz CAM's available which should fit perfect for your project.

I do not know how much load your airplane can take but 200 - 500mW that would be a device which weights almost more then 1 kg not include the camera and power supply for that output power .... I guess in freeair it should be possible with less then 100mW.

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HS0ZFZ   - Swen

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AleG

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Re: 900Mhz, 1.2Ghz or 2.4Ghz?
« Reply #2 on: January 09, 2010, 06:02:21 PM »
Thank you for the answer.

So, 2.4Ghz, hmmm? That would had been my last choice since it's the same as the radio control frequency, so it can't be used with a 2.4Ghz system and I should use a 72Mhz radio and receiver. Nothing too bad about it but 2.4Ghz airplane receivers are much smaller and have much shorter antennas so it's easier to install them on small planes.

As for the power to weight ratio. The kind of transmitter used for this are very small, for example one I have been considering is just a smidgen under 8 grams for a 900Mhz, 500mW transmitter.http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=100&products_id=259
The same shop has a 100mW 2.4Ghz transmitter, but it doesn't state the range. I'll have to check on that.
http://www.nghobbies.com/cart/index.php?main_page=product_info&products_id=10

Offline HS0ZFZ

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Re: 900Mhz, 1.2Ghz or 2.4Ghz?
« Reply #3 on: January 11, 2010, 05:17:17 PM »

Ok AleG

wel go ahead with your plans ... 2.4 GHz for the radio control and 900 MHz for the cam that should be fine I only thought about the 900 MHz GSM basestation which could interfere which your signal ...

Would like to see the airplane taking off ...

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HS0ZFZ   - Swen

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HS0Z EME#2

QTH: OK03jt