ADTech is correct; you are on the wrong side of the building. But there a few more tests you can try using the antennas you have.
It is possible that CHEX is so strong it is overloading your 7777, which will make it impossible to receive your weaker channels.
The first thing you could try is to use the C2 without the "V" dipole, but with the preamp, aimed at CFTO from the balcony. Then try other directions because all your other channels will be coming in as reflections, not direct signals. This will make CHEX weaker as compared to the other channels. I don't know which 7777 you have; the old model with two antenna inputs, or the new 7777 with only one antenna input. If it is the old 7777 connect the C2 to the UHF input and set the switch inside to separate.
C2 > old 7777 > coax > power inserter > TV
If you have the new 7777 with only one antenna input, connect the C2 to a UVSJ using the High/UHF and Common/Line ports, and then to the input of the 7777. The UVSJ will make CHEX much weaker, but you might still be able to receive it.
C2 > UVSJ > new 7777 > coax > power inserter > TV
You can also use the UVSJ with the old 7777 in a similar manner. Connect the C2 to the UVSJ and then to the UHF/Combined input of the 7777 with the inside switch set to combined.
C2 > UVSJ > old 7777 > coax > power inserter > TV
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http://www.solidsignal.com/pview.asp?p=uvsj
http://www.3starinc.com/pico-macom_u..._combiner.html
http://mjsales.net/products/tru-spec...ant=1198505857