how transmit video. via radio.

[siver]

Well, I've the porject of transmit the output of a web cam, to my pc via radio.
I have been reading a lot ofthreads, but I' have not get any clear solution, my knowledge in the radio comunications is so little, and all the discusions that i found where in a other level.
So, if some one know a way to get it, or can give to me some "clue"...
My idea is to found a vide camera module, that compress the video before to send it.

And where could i buy transmitters and receivers online.

thanks

 

[tpetar]

Today you can buy Wifi WebCam, Laser printer, Keyboard, Mouse, Monitor,.... all without cables.

 

[RealAEL]

You would need to create both the hardware and software to do this yourself. Seems unnecessary when it can be done very cheaply already. Just get the complete kit.

**broken link removed**

 

[BigBoss]

If your video signal is analog ( PAL,NTSC etc), you can use a Video Modulator like TDA8822T of NXP..( it's not produced anymore but just an example)Then you can watch it on your TV.It will be a small broadcasting studio.
If you video signal is digital, ( Video Stream,MPEG-2 etc), then you should use a digital modulator to transmit this signal a distance.You may also find digital modulators and demodulators for this purpose.

 

[siver]

ok, first of all, this is a project that i would like to do myself.
So i will find a video compresser for the camera ( i don't konw if the video signal should be analog or digital, but i can get any of them),
About the transmision, if the transmitter is FM, to can transmit the amount of data that a video compressed has, what frecuence do i need, and what bandwidth? and if i use a AM?
What is the size of this kind of transmitters and the cost of it? finaly can i use batteries to supply it.

thanks

 

[betwixt]

Digital video transmission projects are probably beyond the reach of 'home construction', they require very fast computing systems and lots of complex software. To be compatible with dometic TV receivers you have to encode into MPEG2 or H264/H265 and then add the packetizing and streaming ID information and then transmit through QAM/QPSK or OFDM RF generators . It isn't for the feint hearted and everyone I've seen doing it so far is using second-hand commercial equipment. There is one digital transmitter on the market at called "Digilite" but it still needs a fast PC to proces the video before transmission.

You would be far better off using analog without any compression, it costs less by a factor of 100s with presently available technology. Google for "AV transmitter" and you should come up with some designs.

Brian.

 

[siver]

thanks brian, i see that I've to use analog but I'm looking for av transmitters, an they are for very short distance.
What I need, is something that has higher dB, enough to work with a distance of a 4 or more kilometers.
Do you know some thing that I can use?
thanks.

 

[tpetar]

How you plan to interface USB Webcam with digital signal to RF analog ?

What is security ? Everyone can watch your video on their TVs ?

TX for 4km or more is not weak, for sure you need certification and atest for that, there is law regulation for that.

 

[betwixt]

I agree with Tpetar, you need a license to transmit and anything you show can be picked up by others and may also cause interference.

If you accept all that, the easiest solution is to use high-gain antennas at both ends. If you use Yagi antennas, pointing at each other you should see a range improvement of several hundred times so you may be able to use existing low power equipment. The other advantage of directional antennas is the signal is concentrated in one direction and less likely to be seen from other places.

There is another alternative, to use satellite dishes to narrow the beam even further but you need to transmit on much higher frequencies than normal. You can use an analog satellite receiver to pick the signals up. I have done this with 10mW (0.01 Watts) over distances of over 150Km. The design of the transmitter I used is at: http://www.atv-projects.com/Gunn_Diode_Controller.html but note that you also need a Doppler unit to provide the RF. You can often pick these up for very little cost, they are often used in the sensors that detect motion in automatic door openers.

Brian.

 

[siver]

Ok, it seems to be dificult, and before to keep working on it, I want to ask some questions.
First, do you really think that a not engineer can get a sistem like the one that we are talking about?
which would be the cost of a sistem whit antenas?
and the cost of making it with the satelite dishes?

 

[betwixt]

The cost really depends on what you can make yourself or find in surplus market. For example, satellite dishes are quite expensive but you can often find them as scrap metal and get them for nothing. For a Yagi antenna you will probably have to make it yourself anyway, can you get aluminum and are you able to cut and file it into shape?

With almost everywhere going to digital TV these days there are thousands of old analog satellite receivers falling out of use. See if you can get one for nothing or for very low cost. If you tell us where you are it will help us to advise on places to get other components. Edaboard covers the whole World so you may find someone local to you who can help you better.

Brian.

 

[siver]

ok, I think that for the moment I should use a Yagi antena. I can build anything that doesn't need very high electronics level, but whith what transmitter?
and i still dont discard the satelite dishes.
Which one would be the lightest transmitter.

thanks

- - - Updated - - -

ok, I think that for the moment I should use a Yagi antena. I can build anything that doesn't need very high electronics level, but whith what transmitter?
and i still dont discard the satelite dishes.
Which one would be the lightest transmitter.

thanks

 

[RealAEL]

Before you commit to anything you need to refer back to the question that tpetar and betwixt raise earlier about licensing. If you are transmiting over anything more than a short distance (maybe quarter kilometer but often much less) and outside specific portions of the frequency spectrum assigned to a specific service I do not know of any country that would not require some sort of license. Using simple short range services like Bluetooth, WiFi, Wireless Phones or Baby Monitors, FRS Radios (in US) and other similar services no license is required but when you start transmitting kilometers distances without a license then that would almost certainly be illegal. Licenses can be expensive and you would need to ensure that whatever you did would not interfer with any other service.

The easiest method may be to get an Amateur Radio License. That would certainly allow you to set-up a transmit station but there would then be very specific rules about frequency bands and power levels that could be used. There are dedicated bands defined in the available Ham Radio bands for 70 cm, 33cm and 23 cm frequencies to transmit TV video/audio signals.

Amateur Television on Wikipedia

 

[D.A.(Tony)Stewart]

15 yrs ago I used RCA jacked video sender and Receivers that were low cost with a range of 10 meters thru walls. They used colour composite inputs and outputs with some license free band.

Now they are integrated and even IP based wireless cams.. here is one site
https://www.x10.com/homepage.htm