The Tv transmissions are Strong Signal Strength at your location.
Do Not use a amplified antenna.
What directions do ,
windows , patios , balconies , face??
What floor or floors is your condo unit??
What is the top floor of the condo building??
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The Main group of Tv Stations are to the , South West/West.
For better reception using the non amplified HDTVi (not the amplified HDTVa).
As high up as can get the HDTVi antenna.
Put the HDTVi antenna in a ~ South West/South ~ facing , window , patio/balcony glass door window.
As best you can aim the HDTVi antenna at about 180 degree magnetic compass direction , South.
Here is how to aim indoor and outdoor antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Use a Old School magnetic compass to aim antenna.
(If it takes a Long Continues Length of coax running through the condo unit to get the HDTVi connected to the Tv , then So Be It.)
Here are csome places to buy antennas and etc. .
http://www.solidsignal.com.
http://www.amazon.com.
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Digital tuners can develop - Digital Glitches - that are not cleared out with simple channel scans.
Do Double Rescan.
1. Disconnect antenna coax from Tv.
2. Do channel Scan.
3. Unplug Tv from power.
4. Wait a minute or so.
5. Plug Tv into power.
6. Connect antenna coax to Tv.
7. Scan for channels.
http://www.wchstv.com/DoubleRescanAlert.pdf.