Ok , Aim the C5 antenna at about 300 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
The C5 antenna is designed as a VHF high band channels 7 thru 13 antenna.
The C5 also receives UHF band channels 14 thru 51.
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The following Tv stations/channels are to the north west.
WBTW-DT Real Digital VHF high band channel 13 , virtual number (13) CBS and Antenna Tv and MyNetwork.
WPDE-DT Real Digital UHF channel 16 , virtual number (15) ABC.
WWMB-DT Real Digital UHF channel 21 , virtual number (21) CW and CW+.
WFXB-DT Real Digital UHF channel 18 , virtual number (43) FOX and Me-Tv.
WHMC-DT Real Digital VHF high band channel 09 , virtual number (23) PBS channels.
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The following Tv stations/channels are to the , North East.
WSFX-Tv Real Digital UHF channel 30 , virtual number (26) FOX and This Tv.
WECT-DT Real Digital UHF band channel 44 , virtual number (06) NBC.
WWAY-DT Real Digital UHF channel 46 , virtual number (03) ABC and RTV.
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For this - Test - of reception , To Reduce problem situations , Have only 1 Tv connected , no splitters.
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The C5 antenna must clear the roof of the house for reception to the , North West and North East.
And any obstructions that are in the way of reception , will reduce reduce.
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Digital Broadcast Tv Tuners can develop - Digital Glitches - that are not cleared out with simple channel scans.
Do a Double Rescan ,
http://www.dtv.gov/rescan.html.
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This should receive the listed Digital Tv stations channels.
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If not then install a Winegard LNA-100 'Boost' antenna system amplifier.
Must be No other amplifiers in the system , it is the LNA-100 only.
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If still not complete reception of listed channels then will require a second antenna.
However before getting all into the second antenna situation , try reception as recommend first.
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Here are some places to buy reception devices such as the LNA-100 and etc. .
http://www.solidsignal.com.
http://www.amazon.com.
http://www.winegarddirect.com.
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It is Only 1 antenna for now , the C5 that you have.
The second antenna - If it comes to that - will not be another C5.
The second antenna - if it comes to that - will be a UHF only antenna.
Try reception with the C5 antenna that you have First.
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FIRST aim the C5 that you have at about 300 degree magnetic compass direction to start.
Do a Double Rescan.
And adjust the C5 Antenna aim direction - If required - for best reception of the listed channels.
Most Digital Tv's have a signal strength meter and some digital Tv's also have a signal quality meter.