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Doing a RF Video Transmitter project

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kdobson99

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First, let me say that I know virtually nothing about electronics, radio frequencies etc. I am here because it looks like the best place to get some questions answered about a project. Unlike typical projects I see on this board... I'm not building anything from scratch. I just have something I want, that I can't find, but know is possible. Thus, with your help I hope to make it a reality. When responding, please remember to treat me like an idiot because for all intents and puposes dealing with these issues, I am. Now...

I want to transmit an audio video signal from an A/V source (such as my DirecTv receiver) to a handheld wireless lcd monitor. Im sure something better can be designed, but the closest thing on the market that I can find is essentially a handheld baby monitor, such as this: https://www.axiontv.com/www/ProductDetail.asp?did=18
There are several similar handheld devices available and I am not saying that this is the model I will choose, but they all seem to work similarly on a 2.4gHz frequency. The issue I have is... could someone point me to a transmitter device that would match the frequencies used by the handheld unit?

Maybe I don't know the complexities, but I assume if I have an A/V transmitter that transmits on the same frequencies and the handheld receives, I should be able to get picture and sound on the handheld device.

Also, what kind of reception and interference would I likely get? My 2.4 GHz phone seems to cover most of the house and yard, but don't know if the range here would be smaller. Is there anything I can do to improve the range and cut down on interference? The goal here is to be able to walk around the yard (perhaps while mowing) with live TV playing on the handheld device.

Once I have it running, the next mods will be to somehow add RF remote control, perhaps multiple tuners/transmitters so I could have a different channel transmitting to each of the "channels" on the receiver, etc. I actually have a ton of improvements in mind, but need to start with the basics by getting a picture first.

I will have many more questions on the topic, but lets start simple... will this work? What am I not thinking about? It seems so simple and like something everyone would want, but can't find a prepackaged solution anywhere.

Thanks in advance for your help and understanding.
 

IanP

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Re: RF Video Transmitter

To pick-up a channel on your handheld LCD screen you have to tune it to that channel, so if you would like to use you have to make sure that any transmitter will operate within standard TV-channels ..

There are plenty of Channel 0/1 or 33/36 hobby-type video modulators, but, for what you are trying to do, I wouldn't spend much time testing these little gizmos ..

Instead, I would like to encourage you to build a TV transmitter ..

Take a look at the schematic below ( detailed description, including PCB, ... can be found in: https://www.web-ee.com/Schematics/TV_XMIT/TVTransmitb.pdf ) ..
This modulator takes standard linelevel audio and video signals, modulates them (video--> AM, audio --> FM), and transmits the resulting signal up to 100m ..

Regards,
IanP
 

kdobson99

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Re: RF Video Transmitter

I appreciate the advice, but was looking for something that would work with one of the 2.4 GHz handheld receivers. Will it work the way I think? If so, could someone suggest a transmitter to buy? Thanks
 

pic-novato

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Re: RF Video Transmitter

a question, its possible to hand made T1, its very difficult to find.

Thanks
 

biff44

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Re: RF Video Transmitter

You can probably buy a similar transformer from minicircuits for $2 each.
 

pic-novato

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Re: RF Video Transmitter

thanks for your answer biff44, i live in peru, buy this part may be cost US$ 20 for my country include post and taxes. For this i want to made this part

If i omit R9, C5 and all de audio part, the video part will be work?

Sorry for my english. Thanks.
 

pit

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Re: RF Video Transmitter

pic-novato said:
thanks for your answer biff44, i live in peru, buy this part may be cost US$ 20 for my country include post and taxes. For this i want to made this part

The original part won't be of any use for you because is oscillates at 4,5 MHz, which is the subcarrier frequency for NTSC. As PAL has higher picture quality is uses a higher bandwidth, the european PAL system has the audio subcarrier at 5,5 MHz. So you have to modify the circuit to oscillate at 5,5 MHz.

If i omit R9, C5 and all de audio part, the video part will be work?

If you omit the audio section the video section will work. You have to pay attention that by omitting the audio section there is no feedback on the remaining circuit.

This circuit transmits only in VHF I band.


CU
 

pic-novato

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Re: RF Video Transmitter

Thanks Pit

I will be change for 5.5 Mhz.

The video part is ok and i will do it!

A question, the colors of the transformes denotes frequency or other think?
Because i have a lot of them and don't have codes.

Thanks in advance.
 

pit

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Re: RF Video Transmitter

Hello!

For color codes of transformers there is no standard. Please have a look at the manufacturers data sheet, there the color codes are explained.

Some chokes with color rings follow the coding scheme also found on resistors, often expressed in uH, so brown-black-brown is 100 uH for example. Others have their own coding scheme.

CU
 

pic-novato

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Re: RF Video Transmitter

I find web page for toko, but i can´t find for apollo and mitsumi?

Somebody have the web or color codes for help me.

I have a problem with the chokes, any stores have them. I can built them?
Have some tutorial for this?

Thanks
 

pit

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mbyka

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Re: RF Video Transmitter

I need digital rf video and audio link
can you help me please about any schematic or app
 

dibaa

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Re: RF Video Transmitter

please any image foe T1 and what is inside color ?
 

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