The amplifier in the Terk HDTVa model does not and can not 'pull' any signal from the antenna or the air... It is like all other amplifiers, capable of 'pushing' the signal trough the loss of the cable and possible splitter that comes after. Given the typically short length of cable that is often integral to indoor antennas, there is little if any useful purpose for adding an amplifier to the design... unless 'pulling' or 'sucking' more money from your wallet is considered 'useful' by one or both parties to the transaction. (If I'm sounding testy, it's not at you. It's toward the antenna industry that's willing to sell amplifiers when they know they're serving their interests, at your expense.)
If you need more signal due to building penetration loss, use an antenna with more gain. That means you may find yourself using an antenna designed for outdoor installation.
Unfortunately, we have no way to accurately predict the building penetration loss. The least expensive way to gauge the situation would be to spend about $5 on a simple indoor antenna. Try it, then if you have trouble with reception, we can compare the TV Fool prediction to the known capability of the $5 antenna. That would give us a solid point of reference from which to estimate how large an antenna would be needed.
As of 11/29/2011, the
Zenith VN1ANTP1 was priced at under $5 at Amazon. I see it's gone up though.
There are others to consider here:
http://forum.tvfool.com/showthread.php?t=2828