Labs from YSI 95 :
CARA Yerkes Summer Institute, August 1995
This is the staff copy of the lab.
- For the students to learn the basic concepts about radio
transmitters and receivers through the use of physics and
- To learn more about the transmission of wave lengths and how
to calculate the actual wavelength of a transmission.
- To be able to show how polarization is important and the affects it
has on FM band frequencies.
- To introduce the attenuate to the students, find out why body
fading works, and why it is important in radio hunting.
- Also to experimentally see which method of radio hunting works
best by observing and watching the teams work together to find the
- FM stereo transmitter kit
- Hallmark card digital voice recorder
- Lantern Battery
- NE555 timing chip\circuit
- Bread board
- UHF TV antenna ears
- Card board box
- small radio from radio shack
- Aluminum foil
- Paste board or cardboard tube
Polarization - the electrons in light emit classical electromagnetic
waves, just as if the atoms were a little radio antenna. The more
direct light causes the receiver when placed in "hot spots" to have a
stronger and clearer signal. If placed in "cold spots" where there is
little light the signal might appear weaker.
hot spot - place where there is a large accumulation of atoms.
cold spot - place where there is a small accumulation of atoms.
Wavelength - calculate using f(wavelength) = c
A small exercise was developed from a game the HAMs use called
Fox Hunt. This idea enabled us to put together an exercise where
students could have fun learning about transmitters and radio waves.
First the students will be given an introduction about the basic
concepts of radio waves. Then they will be given a parameter in
which the radio is located to prevent them from getting lost. The
radio transmitter will be placed in the front lawn of the Yerkes
Observatory, hidden and known only to the teacher and the teachers
assistant. The best place found was near trees to the east of the
front lawn. The students will be given little hand held FM radios, an
attenuate, and the frequency the transmitter will be transmitting
on. The students will be observed by time and technique. This will
allow us to see what works best since the students will be in teams
The first group of students were broken into twos and team 1 found
the transmitter in 12 minutes but by looking at the trees for it and
not using the attenuater very much. This was a common response
among the students because two of the other teams responded
similarly. It was also found that the teams watched each other as
they looked for the transmitter to see where they went to help them
with there search. The attenuater worked great. Two out of the
three who used it found the transmitter within 12 minutes.
Important Disclaimers and