Science Buddies: "Ask an Expert"

I am doing a project where everyday for 60 days I look at the amount of service bars on a cell phone, and record the weather conditions for that day. I do this in two different locations, and i do each location 2 times everyday. My science teacher wanted me to find out what in the weather particularly impairs electromagnetic radiation. I would really appreciate all the help that I can get. Thank you.

glamourgrl256

I suggest a Google search using the key words - cell phone reception and weather, electromagnetic radiation and weather.

These should get you started.

Matt Mulanax

That's a good project, in my opinion. It's something that people can understand and get their hands around.

This doesn't directly answer your question, but here's some advice about your project design...

One thing you'll have to be careful of is to control all other variables that might affect your experiement, and how you'll work around it. For example, battery strength (always have a fully charged battery), exact location and direction you're facing, same time of day, how crowded the cell network is (how would you compensate for that?), and so on.

One way to test if you're handling all of the variables except for weather might be to analyze your data for something like day of the week versus your bar strength. If it's really only weather that you're measuring, then you should have the same average bars on clear sunny weekdays (Monday through Friday) as you do on clear sunny weekends (Saturday and Sunday).

You could also get a map or something of the closest cell towers to your two locations from your carrier at the beginning of the experiement and at the end. You want to make sure that they don't build a new, closer cell tower in the middle of your experiment. And you'd also want to select locations that are far from cell towers to maximize the effect of weather.

Another potential trouble spot is how you're classifying weather. I don't think that the newspaper weather report over the last 24 hours will be good enough for you. You'll need to develop a way to classify the weather at the point in time that you're making the measurement. The amount of rainfall (none, light, heavy, etc.) might be the big factor in your reception, but I could also see the existance of lightning or storm clouds (even when not raining) being key as well. You're going to have to learn about how to calculate correlation to figure out which of the various factors that you're measuring is key to your reception levels.

A few hints:

What is it about different weather that affect propagation of RF energy? I would start by looking at the water content of the air. Dry, fog, or rain. There is also a frequency dependency, so research for the frequency that your cell phone is operating on.

Since you are using a cell phone signal indicator, you might have the best result if you find a place where dry air produces one less bar than the maximum.

Consider the effects of nearby objects such as buildings, trees, hands. I would make a holding fixture for the phone and clamp it to something for the duration of your testing. Put the phone in it and then stand in exactly the same relative poisition while reading the indicator.

RF measurements can sometimes be rather fickle, and if you are in a null spot the difference of only a few millimeters can be significant at cell phone frequencies.

A significant part of my career has involved making RF measurements using automatic test equipment.

Robert Reavis