Hey I have done this alot few years ago.
Aaj Tak and Tez are not FTA channels.
All you have to do is
Learn the diff between C-Band tarnsmission and Ku-band transmission and select the one to access, Buy an antenna and LNB accordingly. buy a set top box (normally a general sat-tv set top box can recieve both c-band and ku band frequencies)
read some articles online to setup the antenna to correct angles and you will start receiving FTA channels.
For me this was a hobby and I had a big c-band antenna and 4-5 of LNBs and I access a lot of channels from across the globe. (chinese, russian, US, Gulf, etc..)
All this might sound a little complex for a n00b. To make it easier, to just receive India Free channels do this:
1. go to a store in your area selling dish tv products, ask for
a. "ku band LNB"
b. "dish antenna" (used for DD dth or dd direct+ or FreeDish+ (DD dth) not sure what its called now)
c. Coaxial cable (which is used by cable tv operators/ by dth operators)
d. satellite tv set top box.
2. setup the dish antenna and LNB (in correct angle and polarization) on your roof. (follow this link) or search for a better one.
3. Connect the LNB and Set top box with the cable.
4. follow the instruction in the above link (point no. 2) and receive free to air channels.
5. Try different satellites and transponders. use this list of frequencies to search for channels.
6. come back here and post all the fun u had.
Best of Luck !!