"Thank you so much for visiting our class on Friday! The kids loved it...they thought it was pretty cool to meet a "real" Astronomer! Thanks again, Janine"
Updated March 07, 2004
Roof Mounted Antennas
Almost all Junior High Schools in Alberta have flat roofs or a portion of the roof that is flat. Most school roofs are of two part membrane construction, which is easy to punch a hole in. Take care in placing antennas on the roof to make sure the membrane doesn't get punctured.
Locate the antenna on the roof as close as possible to the room where the receiver will be set up and back from the edge of the roof so that, if the antenna does topple in an extremely high wind it will fall to the roof and not to the ground below. Keeping the antenna back from the edge will also reduce the danger of people falling off the roof while working on it.
The objective is to keep the cable run as short as possible to prevent losses of signal energy in the cable. If the cable can drop off the roof and to the classroom window from the antenna that is ideal. But if the cable must travel through ducts or equipment housings on the roof to the receiver, locate the antenna close to the duct. This should shorten the cable run.
The antenna should be located on an area of roof that has as clear a view of the horizon as possible, particularly to the south but also as far north to the east and west as possible. Because of Canada's northerly location, most radio stations we will be listening for will be found to the west, south, or east.
To protect the roof a pallet or some other flat platform such as a piece of plywood needs to be placed on top of a piece of 2.5 or 5 cm UV rated (outdoor) rigid styrofoam insulation. The mast and antenna should be securely fastened to the platform and a couple of 50 pound sand bags placed on top to ensure the antenna and mast don't topple. Alternatively, the antenna mast could be fastened to a vertical wall by brackets and lag bolts.
Running Cable from the Roof
The coax cable can be run through a hole drilled in the window and caulked on either side. Or the cable could be run from the roof through equipment ducting or other access points that already exist on the roof.
Each School Board may have slightly different protocols for permissions on this and your school should consult with the facility director for your Board.
Classroom Mounted Antennas
If you cannot mount your antenna on the roof, you can install it inside your classroom. With enough room you may be able to hang the antenna from the ceiling. Be sure the cable is run in such a way that people cannot trip on it or damage the cable or equipment it is attached to. Cable can be secured to the floor by using duct tape along the length of the cable.