Using the white vent pipe is a temporary mount.
The operative word for antenna height is -->Higher<--.
A Looong pipe can be used to get the antenna Higher.
Antenna mast pipe sections can also be connected together to get the antenna Higher.
And finding a location for the antenna where the trees are lower and less dense in directions of reception.
And trees distance away from antenna is better for directions of reception.
Tv antennas receive better when little to nothing is blocking reception.
Here is a way to get the antenna - Higher -
http://www.ronard.com/Tripods%200703/4712.html.
And then mast pipe sections are put together to make the antenna about 10 feet higher then the top of the tripod antenna mount if required to get reliable reception of the Weak reception Tv transmissions.
No guy wires will be required.
The tripod antenna mount can be moved around on the roof to find a location has the best reception of the Tv transmissions.
Yes the preamplifier can be added now , however the preamplifier is not a substitute for getting the antenna Higher and finding a location where the Tv transmissions are stronger.