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In order to get higher signal level on my pre amplifier to the tv set.

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closed as off-topic by Bence Kaulics, Ricardo, Daniel Grillo, Nick Alexeev Jul 13 '16 at 15:55

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Bence Kaulics, Ricardo, Daniel Grillo, Nick Alexeev
If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ I don't agree with the close votes, this is quite a fundamental question about antennas, not a "how do I connect my TV to my fridge??" type of question. \$\endgroup\$ – pipe Jul 13 '16 at 12:03
  • \$\begingroup\$ @pipe Perhaps if it showed some research it would fair better? \$\endgroup\$ – Bort Jul 13 '16 at 12:09
  • \$\begingroup\$ @Bort Indeed, it's a lazy question, and may deserve a downvote. \$\endgroup\$ – pipe Jul 13 '16 at 12:15
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Yes you can, but unless you understand about phasing, and control the impedance (with non-lossy things like a Wilkinson combiner or a quarter-wave transformer (don't use a lossy 6dB equal split combiner (you'll not get any more signal level))) it's unlikely to give you much benefit, and may make things worse.

It's far better to get a longer antenna, that is a Yagi with more directors.

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    \$\begingroup\$ Good answer; you can actually make reception worse, e.g. by having the antennas' phase center half a wavelength apart. So, OP really shouldn't be doing this, in general. \$\endgroup\$ – Marcus Müller Jul 13 '16 at 9:51
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Can I connect two tv antennas in parallel in order to get higher signal level on my pre amplifier to the tv set.

No you can't.

Without an amplifier and with respect to impedance matching to avoid signal losses on cables due to reflections, no you can't. The matching and summing network means that the loss of each individual signal strength due to summing cancels the overall gain in adding two signals together.

A simple 50 ohm combiner uses three 16.7 ohm resistors - when both inputs and the output are connected, each "port" is correctly terminated. Now, if the two input ports were fed from an identical signal sourced twice through two 50 ohm source impedances you would get this: -

enter image description here

If you did the calcs/math you will find that you get exactly the same signal voltage feeding the output 50 ohm (R6) as you would from one source (with its 50 ohm impedance) directly feeding R6 i.e. a signal that is reduced by 6 dB.

You also have to be aware that each antenna has to be positioned so as not to "steal" the power received by the other antenna - you might get lucky with this but that won't help alleviate the situation in my 1st paragraph.

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