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I want to make a device which gets the TV antenna signals and transmits it again. Is there any module available in market which simplifies construction or i should make from scratch? Since my background is in software, please explain simple.

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closed as off-topic by Leon Heller, Scott Seidman, Daniel Grillo, Bence Kaulics, Dave Tweed Aug 16 '16 at 13:24

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    \$\begingroup\$ Transmit at same frequency or a different frequency and, what power output? \$\endgroup\$ – Andy aka Aug 16 '16 at 8:26
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    \$\begingroup\$ I'm voting to close this question as off-topic because such a device is illegal. \$\endgroup\$ – Leon Heller Aug 16 '16 at 10:42
  • \$\begingroup\$ @LeonHeller I can't see any correlation between on-topicness and legality. \$\endgroup\$ – Marcus Müller Aug 16 '16 at 10:44
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    \$\begingroup\$ Encouraging an illegal act is generally illegal. \$\endgroup\$ – Leon Heller Aug 16 '16 at 10:46
  • \$\begingroup\$ @LeonHeller nothing encouraging about answering this question. Still, legality != on-topicness. Also, pretty sure that answering a question is covered by free speech, and also, not anyone's job to censor knowledge of how things can be done, and also, what's illegal encouragement is subject to individual jurisdiction; and as far as I can tell, neither of us is a judge, \$\endgroup\$ – Marcus Müller Aug 16 '16 at 10:47
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What you describe definitely contains an amplifier; small-amplitude signals go in, high-amplitude signals go out.

Now for problems:

  • If you're on the same frequency as the received signal, your amplified signal will interfere with the received, weak signal. Hence, same-frequency forwarding can only work if the "end receiver" only gets one of the two signals, not a combination of both. For cable TV, that is the case, so that's why you can get very cheap UHF amplifiers. For antenna TV, that's not the case, so you can't have same frequency relaying.
  • If you need to change the frequency while relaying, you need what is often called a transverter: The received signal is pre-amplified, mixed with a single tone that shifts everything in frequency, and transmitted through a power amplifier. This is significantly more complex.

In either case, you'll need proper input and output filters (which will be very complex, considering the TV spectrum isn't necessarily one continuous block) and you will be operating illegally, with a device that, per definition of what it does, is easy to find. I don't know where you live, but I don't think there's any place on earth I'd do this.

Regarding the question of building such a device yourself:

Well, it's certainly not a starter project for electronics beginners; TV signals, even the ones that "look bad on screen" are sent with relatively high power by the "official" TV towers, compared to the powers that e.g. are in the cell phone signals that reach your telephone. So this will be a challenge in amplification, testing, power supply, filtering, mixing, tone generation and general RF design, which is a discipline on its own.

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  • \$\begingroup\$ The idea of making such device is in my home the Tv should be near the antenna plug that limits me for proper tv place. I wanted this device to connect to antenna plug and the other receiver to the TV Av in port \$\endgroup\$ – ehsan toghian Aug 16 '16 at 11:35
  • \$\begingroup\$ um, use a longer cable? \$\endgroup\$ – Marcus Müller Aug 16 '16 at 11:36
  • \$\begingroup\$ It is neater solution to be cable-less! \$\endgroup\$ – ehsan toghian Aug 16 '16 at 11:42
  • \$\begingroup\$ no, in this situation, I'd disagree. \$\endgroup\$ – Marcus Müller Aug 16 '16 at 12:17
  • \$\begingroup\$ If you're just trying to distribute TV within your house, there are commercial products designed specifically to do this. \$\endgroup\$ – Dave Tweed Aug 16 '16 at 13:23

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