How to trouble shoot week signals for some channels

Recently I experienced that I couldn't get only few channels on Tata Sky.I observed that if I touched the set box these channels would appear!The conclusion was that there was nothing wrong in Set Box or in the antenna.I cleaned both ends, one at the Set box and other at the antenna. Now I am getting all the channels without any difficulty. Incidentally I was informed, by an email and verbally on the telephone that the customer owns the antenna and not the property of the Tata Sky, Hence customer is free to repair the antenna.sureshparanjape