Hi,
I have seen many people transmit data up to 500km with radiometrix module. My question is: it's possible to transmit live video in that range? I want a guide about how this module work an if it's easy an example code to understand this module.
Thanks
500km?
Do you mean 500 metres?
Looking on the RadioMetrix website, and at the NRX2, they claim a usable range over 500 metres, but not that much over 500 metres!
See this page:-
NRX2 UHF Narrow Band FM Receiver
Do you have any examples you can link to proving "I have seen many people transmit data up to 500km" ?
It sounds crazy but no I mean 500 km see that page http://ava.upuaut.net/store/index.php?route=product/product&product_id=92
Using high altitude balloons and properly oriented, high gain Yagi antennas, ranges in excess of 500 km have been achieved on a few occasions with such 10 mW transmitters.
For the module in question see this: Getting started with the NTX2B and the Arduino – Part 1 The Basics | Ava High Altitude Balloon Project The baud rate was 50, so video is completely out of the question.
DimitrisTzam:
It sounds crazy but no I mean 500 km see that page http://ava.upuaut.net/store/index.php?route=product/product&product_id=92
Don't believe everything you read. The Wiki records page linked to by the 'http://ava.upuaut.net' page says nothing about 433MHz. It does say that those records are for 10mW transmitters though, but they'd be at a much lower frequency / longer wavelength to achieve those amazing distances.
Believe me, if the Radiometrix modules were capable of anything like that, it would be splattered all over their website. They claim a maximum of 500m for good reason. That could well be only in a line-of-sight situation, too. The 10mW 433MHz modules that I use can achieve 1000m line-of-sight, but only 50m in normal situations where there are obstacles.
Also, in the Wiki, check out the baud rates quoted for those records under the 10mW heading - 50 baud to 300 baud. Nowhere near what you'd need for video. Video would require a higher bandwidth than the NRX2 and similar transmitters provide, too. The Radiomatrix NRX2 etc are only really suited to data transmission.
jremington:
Using high altitude balloons and properly oriented, high gain Yagi antennas, ranges in excess of 500 km have been achieved on a few occasions with such 10 mW transmitters.For the module in question see this: Getting started with the NTX2B and the Arduino – Part 1 The Basics | Ava High Altitude Balloon Project The baud rate was 50, so video is completely out of the question.
We were typing at the same time. Do you mean with 433MHz, or lower frequencies? I think that 433MHz would be pushing it, regardless of high-altitude and high-gain antennas.
Edit: jremington, I just checked out the page you linked. There's no mention of 500km range there. How high does the balloon get?
It is very clear that the balloon project linked is using 434 MHz. AVA Hardware | Ava High Altitude Balloon Project
jremington:
It is very clear that the balloon project linked is using 434 MHz. AVA Hardware | Ava High Altitude Balloon Project
Yes, I read that after posting my last reply. I saw nothing about 500km range with 433MHz though.
I have seen at least 4 or 5 websites claim this range..also on one of this he sent photos from his weather ballon..Also its possible to archive 200km range with high gain antennas and these modules?
this module write on top 25khz uhf 10mw but on websites they say about 433 mhz
DimitrisTzam:
I have seen at least 4 or 5 websites claim this range..
Well it must be true then. 
also on one of this he sent photos from his weather ballon.
Weather balloons don't get to 500km high though. More like <30km. The record is about 30km altitude, and that's for the high-altitude balloon linked to earlier by jremington, not a simple weather balloon.
Also its possible to archive 200km range with high gain antennas and these modules?
You're expecting way too much of these little 10mW modules. Don't expect more than several hundred metres at gound level with a high-gain antenna, and consider yourself extremely lucky if you get that much. And without such an antenna, expect a max of about 50 metres. As I mentioned earlier, the manufacturer states 500 metres max for very good reason. I can see that you intend to try, but you'll be sadly disappointed. And video is totally out of the question.
this module write on top 25khz uhf 10mw but on websites they say about 433 mhz
That's 25kHz bandwidth. Operating frequency is ~433 MHz as stated.
they send gps data but I dont now...also there is way to send data at range of 200 km in clear area with not big enough transmitters?
DimitrisTzam:
they send gps data but I dont now...also there is way to send data at range of 200 km in clear area with not big enough transmitters?
At this point, I can only repeat what I've already said, but you don't want to hear it. I'm just wasting my time.
Here's a link to a high-gain Yagi antenna for 433MHz. For decent range, it's intended for powers up to 150W. And even they wouldn't have a 500km range. The modules you're looking at have 0.01W.
433MHz Yagi
no of course I hear you and I ask if there is way to transmit data in a range of 200km...for example if a weather ballon was in height of 200kg I could transmit data on this with a transmitter of 25waat for example in low frequencies and high gain antennas?
Don't you need a radio operator license to transmit with that much power, and at that altitude?
DimitrisTzam:
no of course I hear you and I ask if there is way to transmit data in a range of 200km...for example if a weather ballon was in height of 200kg I could transmit data on this with a transmitter of 25waat for example in low frequencies and high gain antennas?
Weather balloons don't even get close to 200km altitude. Only usually 18km to 37km.
Regarding distance vs power for LF transmitters, that's really a question for an RF expert. I'm just another user of 10mW 433MHz RF modules, (APC220 and Dorji DRF7020-D13), and can only speak from personal experience with them.
And I'm pretty sure CrossRoads is correct. Another factor to take into consideration.
i didnt see your last reply so forget reply 12
the strange thing is that the voyager spaceship witch is 18,634,314,372.96 km away can transmit signals on s-band haw does it do it? it use only a transmitter of 23watt
transmit signals on s-band haw does it do it?
Very, very slowly, using forward error correction, line of sight, with extremely high gain and extremely directional antennas on both ends.
jremington:
Very, very slowly, using forward error correction, line of sight, with extremely high gain and extremely directional antennas on both ends.
No atmosphere to get in the way for most of the journey, either.
I have seen on rc some modules that convers 2.4ghz on mhz and it can transmit it over 40km so I could make a converter like this to transmit data further?