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I would like to know your opinion what are existing solutions for building a small (<5W) UHF TV transmitter. The problem is every circuit or schematics I find already uses separate audio/video input, whereas I already have modulated RF signal coming from a TV modulator like this: https://www.ebay.com/itm/PAL-B-G-Composite-RCA-Video-Audio-To-PAL-B-G-RF-UHF-VHF-CATV-Modulator-/192160908653, so in the end I have 75 Ohm compatible signal already.

So the questions are:

  1. Can I just hook up something like this https://www.ebay.com/p/533392191 just to transmit signal aerial?
  2. Do I need to use a wideband amplifier because I also want to use a stereo sound (MTS/NICAM/A2)?
  3. Wouldn't it be simpler to design RF modulator + amplifier from scratch to overcome aforementioned issues?

Thanks a lot!

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closed as too broad by Andy aka, Dmitry Grigoryev, Michel Keijzers, Chris Stratton, laptop2d Apr 10 '18 at 18:41

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ Do you have schematics of the parts? Can you ask a more direct question without asking for opinions? \$\endgroup\$ – Andy aka Apr 10 '18 at 13:11
  • \$\begingroup\$ I don't have yet and that's why I'm asking - I don't want to spend money on stuff I won't need :) \$\endgroup\$ – user37741 Apr 10 '18 at 15:35
  • \$\begingroup\$ @ashtutosh thanks a lot! can you give an example of such rf power amplifier? \$\endgroup\$ – user37741 Apr 11 '18 at 16:56
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Can I just hook up something like this https://www.ebay.com/p/533392191 just to transmit signal aerial?

No, It is an LNA (Low Noise Amplifier) and LNAs are not generally used in the transmitter side because of their low IIP3 values ( i.e. LNAs will easily distort input signal when the input power is quite large. They are excellent amplifiers when input power is low and thus they are used in receiving end). For transmitter side, you should use power amplifier.

Do I need to use a wideband amplifier because I also want to use a stereo sound (MTS/NICAM/A2)?

Sound type, mono or stereo, is not relevant for deciding bandwidth of RF amplifier. The amplifier you choose should cover the all TV channel frequencies you would like use. As you said that you are operating in UHF, so 0.1-2000 Mhz power amplifier would be a good choice.

Wouldn't it be simpler to design RF modulator + amplifier from scratch to overcome aforementioned issues?

No, if you don't have a good electronics background. Even if you are experienced with designing such stuff from scratch, I am sure you can get readymade things which you can connect together and get your setup working.

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