Newbie here. Well, ... a newbie to this web site anyway.
I once heard an author on a radio talk show that said, "A lot of reading does not an expert make."
I have always remembered that quote - even if I forgot the author's name.
So, I am no expert, I am just sharing something I read here, in this forum:
I read a book on solar power, long, long, ago that came from the Mother Earth News library. In this book there was a chapter on how to make a parabolic curve with a precise (enough) focal point using just a carpenter's square. I have used this knowledge to make High Gain antenna reflector's for my cell phone. Since I can pick my exact focal length - I get impressive increases in the bars on my cell phone when the phone is placed in the sweet spot of the focus of the reflector. I made a cheap carboard box with the reflecting foil inside. All I have to do is place the phone on the box and the focal point is exactly 3/8 of an inch above the cardboard, marked by a line. Since my office is in the basement of the building I don't worry about pointing it toward the tower. Signals, weak though they may be, are bouncing everywhere. I focus enough energy to be able to take calls. Since I use bluetooth, I just leave the phone on the box.
This plotting of the curve for a parabolic shape can be used to make a solar cooker as well. One that could make a hot spot that would burn paper at the exact focal point. IF you used broken shards of mirror on your parabolic shape. Making one takes some construction skill. However, by raising and lowering the pot thru the focal point you can control the temperature of the food. All the energy goes where you want it.
I realize at this point I need to share illustrations and examples. So all I can do tight now, tonight, is offer the teaser that is is possible to plot this parabolic curve with just a square and a pencil. No quadratic equations needed at all. Unless you are needing the precision of the Hubble Telescope or something like that.
So reply to this post and show me how many folks are interested in this obscure method of reflector design..
By the way - a parabolic is a parabolic no matter what you are trying to focus. This method will also make a "big ear" microphone if that is what you want to do. This is because particles of any size bounce off of a reflector with the same angle of incidence per known laws of physics. So the focal point works for sound, radio waves and light from the sun.
For now - just letting you all know the method exists.
I once heard an author on a radio talk show that said, "A lot of reading does not an expert make."
I have always remembered that quote - even if I forgot the author's name.
So, I am no expert, I am just sharing something I read here, in this forum:
I read a book on solar power, long, long, ago that came from the Mother Earth News library. In this book there was a chapter on how to make a parabolic curve with a precise (enough) focal point using just a carpenter's square. I have used this knowledge to make High Gain antenna reflector's for my cell phone. Since I can pick my exact focal length - I get impressive increases in the bars on my cell phone when the phone is placed in the sweet spot of the focus of the reflector. I made a cheap carboard box with the reflecting foil inside. All I have to do is place the phone on the box and the focal point is exactly 3/8 of an inch above the cardboard, marked by a line. Since my office is in the basement of the building I don't worry about pointing it toward the tower. Signals, weak though they may be, are bouncing everywhere. I focus enough energy to be able to take calls. Since I use bluetooth, I just leave the phone on the box.
This plotting of the curve for a parabolic shape can be used to make a solar cooker as well. One that could make a hot spot that would burn paper at the exact focal point. IF you used broken shards of mirror on your parabolic shape. Making one takes some construction skill. However, by raising and lowering the pot thru the focal point you can control the temperature of the food. All the energy goes where you want it.
I realize at this point I need to share illustrations and examples. So all I can do tight now, tonight, is offer the teaser that is is possible to plot this parabolic curve with just a square and a pencil. No quadratic equations needed at all. Unless you are needing the precision of the Hubble Telescope or something like that.
So reply to this post and show me how many folks are interested in this obscure method of reflector design..
By the way - a parabolic is a parabolic no matter what you are trying to focus. This method will also make a "big ear" microphone if that is what you want to do. This is because particles of any size bounce off of a reflector with the same angle of incidence per known laws of physics. So the focal point works for sound, radio waves and light from the sun.
For now - just letting you all know the method exists.
