Now there is just a few things for your information.
I use an extension coaxial cable joined with an adaptor to create the extended length. I was worried that in the event signal goes weak I can simply moves the antennae to the window then.
I also have another device HDMI cable going through the feature wall lobang.
Was happy with the setup then realized that the signal from Channel U HD gets erratic (image freezing, mosaic, no signal .......) only this channel whenever I power up the Xbox HDMI connection.
Tested the direct connection with the antennae cable to TV without going through the lobang and signal was normal again.
Therefore changed the HDMI cable to those with better insulation and ferrite ring at both end (HDMI 2.0) type.
This time signal was stable but gets cut-off intermittently.
Then by chance I touch the coaxial joint adaptor (which is metal) and there was static charges.
Wrapped it with those rubber electrical tape (not plastic type) and problem solved.
Now Channel U HD (highest frequency) signal both stable and strong without any interference.
Hope this helps with your plan on your set up.