Directional antenna for i Phone

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I possess an old and/or a new i Phone. My problem is that on the Almhtte 1700m only a very reduced receipt is. Since I would shift my office in August gladly there, I need however a safe signal.
Now I procured myself a directional antenna, but the I Phone has no antenna input.
On this side equipment is shown that is to help!

http://de.sourcingmap.com/gsm-mobile...r-p-32564.html

Who can help me for my problem?

lg sixi

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Shifted after general, because that is indeed no Fritz WLAN problem