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A question about radio, sound, "wave length" etc.
OK, I picked this up on another board,a nd seeing that Eisboch, Tom,
Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr |
A question about radio, sound, "wave length" etc.
On Jan 15, 7:50 pm, Tim wrote:
OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Amplitude is not a length but has other units, for example with sound, amplitude has units of pressure. With light, radio waves or other electromagnetic radiation, the amplitude is electric or magnetic field. Consider the wavelength of your VHF which is roughly about the length of your 8' antenna. The wavelength of the microwaves in your microwave oven is roughly 3 cm (just over an inch). The wavelength of your cell phone waves is somewhat longer than those in a microwave, about 3X. Infrared light has a a wavelength as small as .5 micron or about . 00002". Visible light has length between .5 micron (red) and .3 micron (violet). Vacuum Ultraviolet goes from there down to about 120 angstroms (1 angstrom =1 X10-10 m), soft x-rays from there down to roughly 6 angstroms and the x-rays your dentist uses down to about .6 angstroms. Gamma rays can be very short. At the other end of the spectrum, Extremely Low Frequency waves have lengths comparable to the diameter of the earth. Remember the old AM radio towers, they were about the length of the AM radio waves. Your AM radio had a long antenna cuz the AM waves were long whereas the FM waves are much shorter hence the smaller FM antenna. I am sure this is MUCH more than you wanted to know but AT LAST, I get to expound on something I know something about (I make x-ray mirrors for waves that have lengths of anywhere from 120 angstroms to 1.2 angstroms). Now, about boats...... |
A question about radio, sound, "wave length" etc.
On Jan 15, 7:07*pm, wrote:
On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought *I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell *the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. *Amplitude is not a length but has other units, for example with sound, amplitude has units of pressure. *With light, radio waves or other electromagnetic radiation, the amplitude is electric or magnetic field. *Consider the wavelength of your VHF which is roughly about the length of your 8' antenna. *The wavelength of the microwaves in your microwave oven is roughly 3 cm (just over an inch). *The wavelength of your cell phone waves is somewhat longer than those in a microwave, about 3X. Infrared light has a a wavelength as small as .5 micron or about . 00002". *Visible light has length between .5 micron (red) and .3 micron (violet). *Vacuum Ultraviolet goes from there down to about 120 angstroms (1 angstrom =1 X10-10 m), soft x-rays from there down to roughly 6 angstroms and the x-rays your dentist uses down to about .6 angstroms. *Gamma rays can be very short. At the other end of the spectrum, Extremely Low Frequency waves have lengths comparable to the diameter of the earth. *Remember the old AM radio towers, they were about the length of the AM radio waves. *Your AM radio had a long antenna cuz the AM waves were long whereas the FM waves are much shorter hence the smaller FM antenna. I am sure this is MUCH more than you wanted to know but AT LAST, I get to expound on something I know something about (I make x-ray mirrors for waves that have lengths of anywhere from 120 angstroms to 1.2 angstroms). Now, about boats......- Hide quoted text - - Show quoted text - OK, about boats. handy to know whats going on when using a ship to shore radio ?: |
A question about radio, sound, "wave length" etc.
wrote in message ... On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Amplitude is not a length but has other units, for example with sound, amplitude has units of pressure. With light, radio waves or other electromagnetic radiation, the amplitude is electric or magnetic field. Consider the wavelength of your VHF which is roughly about the length of your 8' antenna. The wavelength of the microwaves in your microwave oven is roughly 3 cm (just over an inch). The wavelength of your cell phone waves is somewhat longer than those in a microwave, about 3X. Infrared light has a a wavelength as small as .5 micron or about . 00002". Visible light has length between .5 micron (red) and .3 micron (violet). Vacuum Ultraviolet goes from there down to about 120 angstroms (1 angstrom =1 X10-10 m), soft x-rays from there down to roughly 6 angstroms and the x-rays your dentist uses down to about .6 angstroms. Gamma rays can be very short. At the other end of the spectrum, Extremely Low Frequency waves have lengths comparable to the diameter of the earth. Remember the old AM radio towers, they were about the length of the AM radio waves. Your AM radio had a long antenna cuz the AM waves were long whereas the FM waves are much shorter hence the smaller FM antenna. I am sure this is MUCH more than you wanted to know but AT LAST, I get to expound on something I know something about (I make x-ray mirrors for waves that have lengths of anywhere from 120 angstroms to 1.2 angstroms). Now, about boats...... Can you shave in those mirrors? 8-) BTW, good explanation. |
A question about radio, sound, "wave length" etc.
On Jan 15, 8:33 pm, JG2U wrote:
On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." It's the distance, or "length", that the signal in question would travel while transitioning through a complete cycle. An audible signal will generally travel at the speed of sound, and light (different wavelengths, different colors) will travel at the speed of light. Does that help? HOWEVER, Sometimes a wave amplitude can be a length, for example a wave on the surface of water or a wave on the surface of a drum. Basically, these are special cases. Sorry, i forgot these obvious examples. The x-ray mirrors are seriously shiny but look like small cones with holes at both ends. They are made of metal (electroformed nickel) with an inner surface of gold. If you hold them up to the sun, they will concentrate the sunlight like a parabolic mirror would. I'll resist the urge to go on and on about how they work and bore you to death. NOW, could somebody please explain Hull Speed? |
A question about radio, sound, "wave length" etc.
On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim
wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. Wavelength is the length measurement from the beginning to the end of one full cycle. Or think of it another way, the distance a wave at a given frequency to travel from 0 degrees to 360 degrees. Frequency is the number of wave periods passing a point in time and is inversely proportional to wavelength - the higher the frequency of the signal, the shorter the wavelength. |
A question about radio, sound, "wave length" etc.
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A question about radio, sound, "wave length" etc.
Personally, I'm neutral. :)
Better than being neutered! ;-) --Mike "Short Wave Sportfishing" wrote in message ... On Tue, 15 Jan 2008 17:51:42 -0800 (PST), wrote: NOW, could somebody please explain Hull Speed? We had a discussion of this a year or so ago. As I remember, it turned heated because of the terms used - hull speed vs speed/length ratio. Personally, I'm neutral. :) |
A question about radio, sound, "wave length" etc.
"Short Wave Sportfishing" wrote in message ... On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. Wavelength is the length measurement from the beginning to the end of one full cycle. Or think of it another way, the distance a wave at a given frequency to travel from 0 degrees to 360 degrees. Frequency is the number of wave periods passing a point in time and is inversely proportional to wavelength - the higher the frequency of the signal, the shorter the wavelength. And by the way Tim .... the "waveform" need not be sinusoidal. It could be a square wave, sawtooth, virtually anything. For practical purposes to us, the wavelength is important in determining the proper electrical length of an antenna for maximum power transfer and resultant radiation. Ideally, the antenna would be "cut" (it's electrical length) to the physical wavelength of the transmitting frequency, or an even fraction of it, (i.e. 1/2 wavelength, 1/4 wavelength, 1/8, etc.) A mismatch, meaning the antenna is electrically too short or too long, causes out of phase "standing waves" to be set up in the antenna and/or transmission line (coax) that is reflected back to the transmitting radio, effectively decreasing the radio's transmitting power. The measurement of reflected power to transmitted or "forward" power is what is referred to as the "Standing Wave Ratio" or "SWR". In high power applications, a high reflected standing wave can damage the radio and/or transmission line. I've burned up transmission lines several times trying to apply high power RF into a plasma contained in a vacuum chamber. Hate that when it happens. It's unlikely that low power transmitters like a VHF marine radio would be damaged (unless there was a direct short on the antenna or line) due to a mismatch, but it *will* cut done on the effective radiated power. Your marine radio, rated at 25 watts is actually transmitting much less, especially if the antenna is not matched or "cut" properly. Eisboch |
A question about radio, sound, "wave length" etc.
On Jan 15, 8:51*pm, wrote:
On Jan 15, 8:33 pm, JG2U wrote: On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought *I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell *the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." It's the distance, or "length", that the signal in question would travel while transitioning through a complete cycle. An audible signal will generally travel at the *speed of sound, and light (different wavelengths, different colors) will travel at the speed of light. Does that help? HOWEVER, Sometimes a wave amplitude can be a length, for example a wave on the surface of water or a wave on the surface of a drum. Basically, these are special cases. *Sorry, i forgot these obvious examples. The x-ray mirrors are seriously shiny but look like small cones with holes at both ends. *They are made of metal (electroformed nickel) with an inner surface of gold. *If you hold them up to the sun, they will concentrate the sunlight like a parabolic mirror would. *I'll resist the urge to go on and on about how they work and bore you to death. NOW, could somebody please explain Hull Speed?- Hide quoted text - - Show quoted text - Hull speed is basically the maximum speed at which a displacement type hull can move through the water before climbing the bow wave and planing off... |
A question about radio, sound, "wave length" etc.
"Short Wave Sportfishing" wrote in message ... On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. Wavelength is the length measurement from the beginning to the end of one full cycle. Or think of it another way, the distance a wave at a given frequency to travel from 0 degrees to 360 degrees. Frequency is the number of wave periods passing a point in time and is inversely proportional to wavelength - the higher the frequency of the signal, the shorter the wavelength. What sort of tool would you use to measure wavelength.? |
A question about radio, sound, "wave length" etc.
On Wed, 16 Jan 2008 00:19:55 -0500, "Eisboch" wrote:
"Short Wave Sportfishing" wrote in message .. . On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. Wavelength is the length measurement from the beginning to the end of one full cycle. Or think of it another way, the distance a wave at a given frequency to travel from 0 degrees to 360 degrees. Frequency is the number of wave periods passing a point in time and is inversely proportional to wavelength - the higher the frequency of the signal, the shorter the wavelength. And by the way Tim .... the "waveform" need not be sinusoidal. It could be a square wave, sawtooth, virtually anything. For practical purposes to us, the wavelength is important in determining the proper electrical length of an antenna for maximum power transfer and resultant radiation. Ideally, the antenna would be "cut" (it's electrical length) to the physical wavelength of the transmitting frequency, or an even fraction of it, (i.e. 1/2 wavelength, 1/4 wavelength, 1/8, etc.) A mismatch, meaning the antenna is electrically too short or too long, causes out of phase "standing waves" to be set up in the antenna and/or transmission line (coax) that is reflected back to the transmitting radio, effectively decreasing the radio's transmitting power. The measurement of reflected power to transmitted or "forward" power is what is referred to as the "Standing Wave Ratio" or "SWR". In high power applications, a high reflected standing wave can damage the radio and/or transmission line. I've burned up transmission lines several times trying to apply high power RF into a plasma contained in a vacuum chamber. Hate that when it happens. It's unlikely that low power transmitters like a VHF marine radio would be damaged (unless there was a direct short on the antenna or line) due to a mismatch, but it *will* cut done on the effective radiated power. Your marine radio, rated at 25 watts is actually transmitting much less, especially if the antenna is not matched or "cut" properly. Another term that Tim will probably run into is Effective Radiated Power or ERP. ERP is a measure of total radiated power - subtracting system losses to the system gains resulting in ERP as measured in Decibels (dB). ERP is nominally referenced to a resonant 1/2 wave dipole (or a center fed antenna 1/2 wavelength of any given frequency - 1/4 wave length on either side of the center feed point) in free space radiating in a given direction. In theory, for every 3 dB of gain, the ERP, theoretically, will double. For example, in theory, if you have 6 dB of gain and 3dB of loss, the ERP is 3 dB. The free space multiplier is 2.1. If you input 25 watts to an antenna with 3 dB gain, the ERP will be a theoretical 50 watts. |
A question about radio, sound, "wave length" etc.
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A question about radio, sound, "wave length" etc.
|
A question about radio, sound, "wave length" etc.
"Jim" wrote in message ... What sort of tool would you use to measure wavelength.? A wavelength measurer, of course. Or, you could use this: http://www.csgnetwork.com/freqwavelengthcalc.html Eisboch |
A question about radio, sound, "wave length" etc.
|
A question about radio, sound, "wave length" etc.
"Eisboch" wrote in message ... "Jim" wrote in message ... wrote in message ... On Tue, 15 Jan 2008 17:07:42 -0800 (PST), wrote: On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Wavelength is usually stated as "Peak to Peak", or pp which is 180 degrees, right? ;- 360 degrees. Eisboch in 30 degrees I count 3 peaks. All this wondering is going to cause me to loose consciousness. ;- ;- |
A question about radio, sound, "wave length" etc.
"Eisboch" wrote in message ... "Jim" wrote in message ... What sort of tool would you use to measure wavelength.? A wavelength measurer, of course. Or, you could use this: http://www.csgnetwork.com/freqwavelengthcalc.html Eisboch I would prefer something simple like a formula or pocket sized measuring tool. This wavelength stuff just doesn't make sense. I think there must be more to the equasion besides frequency and meters like the speed of light or sound or megapixles per googles. |
A question about radio, sound, "wave length" etc.
On Wed, 16 Jan 2008 06:08:54 -0500, "Jim"
wrote: "Short Wave Sportfishing" wrote in message .. . On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. Wavelength is the length measurement from the beginning to the end of one full cycle. Or think of it another way, the distance a wave at a given frequency to travel from 0 degrees to 360 degrees. Frequency is the number of wave periods passing a point in time and is inversely proportional to wavelength - the higher the frequency of the signal, the shorter the wavelength. What sort of tool would you use to measure wavelength.? A wavelength meter. BBAAWWWAAAHHHAAA!!! Um... It's determined by a simple algebraic equation. Speed of Light (300 m/s) = Frequency times Wavelength. or 300 = F*W or Wavelength = 300(speed of light in meters) divided by F (Megahertz). That's how it's done. |
A question about radio, sound, "wave length" etc.
On Wed, 16 Jan 2008 07:07:32 -0500, "Eisboch" wrote:
"Jim" wrote in message .. . What sort of tool would you use to measure wavelength.? A wavelength measurer, of course. Dammit - beat me to it. (Note to self - always read the thread before commenting) Or, you could use this: http://www.csgnetwork.com/freqwavelengthcalc.html Oh - that's neat. |
A question about radio, sound, "wave length" etc.
On Wed, 16 Jan 2008 07:45:37 -0500, "Jim"
wrote: "Eisboch" wrote in message ... "Jim" wrote in message ... What sort of tool would you use to measure wavelength.? A wavelength measurer, of course. Or, you could use this: http://www.csgnetwork.com/freqwavelengthcalc.html Eisboch I would prefer something simple like a formula or pocket sized measuring tool. This wavelength stuff just doesn't make sense. I think there must be more to the equasion besides frequency and meters like the speed of light or sound or megapixles per googles. Space monkeys per Barrel times pounds of fish in a basket. Hey, works for me. |
A question about radio, sound, "wave length" etc.
"Jim" wrote in message ... "Eisboch" wrote in message ... "Jim" wrote in message ... What sort of tool would you use to measure wavelength.? A wavelength measurer, of course. Or, you could use this: http://www.csgnetwork.com/freqwavelengthcalc.html Eisboch I would prefer something simple like a formula or pocket sized measuring tool. This wavelength stuff just doesn't make sense. I think there must be more to the equasion besides frequency and meters like the speed of light or sound or megapixles per googles. Wavelength = speed divided by frequency. For RF, speed is the speed of light, or 186,000 miles per second, or for antenna length purposes, 299,792,458 meters per second. Freq is the frequency in hertz or hz or Hz or cycles per second or whatever they call it now. You do the math. I use the simple little web page computer calculators, like: http://eosweb.larc.nasa.gov/EDDOCS/wavelength.html Eisboch |
A question about radio, sound, "wave length" etc.
"Eisboch" wrote in message ... "Jim" wrote in message ... "Eisboch" wrote in message ... "Jim" wrote in message ... What sort of tool would you use to measure wavelength.? A wavelength measurer, of course. Or, you could use this: http://www.csgnetwork.com/freqwavelengthcalc.html Eisboch I would prefer something simple like a formula or pocket sized measuring tool. This wavelength stuff just doesn't make sense. I think there must be more to the equasion besides frequency and meters like the speed of light or sound or megapixles per googles. Wavelength = speed divided by frequency. For RF, speed is the speed of light, or 186,000 miles per second, or for antenna length purposes, 299,792,458 meters per second. Freq is the frequency in hertz or hz or Hz or cycles per second or whatever they call it now. You do the math. I use the simple little web page computer calculators, like: http://eosweb.larc.nasa.gov/EDDOCS/wavelength.html Eisboch I knew you would know that. Tom too. |
A question about radio, sound, "wave length" etc.
"Jim" wrote
What sort of tool would you use to measure wavelength.? A frequency counter. |
A question about radio, sound, "wave length" etc.
"Ernest Scribbler" wrote in message et... "Jim" wrote What sort of tool would you use to measure wavelength.? A frequency counter. Sombody already answered, but thanks anyway. |
A question about radio, sound, "wave length" etc.
"Jim" wrote
Sombody already answered, but thanks anyway. I know, but I thought you might be interested in a correct answer... |
A question about radio, sound, "wave length" etc.
wrote in message ... It can be measured using an oscilloscope. You can measure the amplitude and frequency. You'd have to calculate the wavelength. Eisboch |
A question about radio, sound, "wave length" etc.
wrote in message ... On Wed, 16 Jan 2008 06:49:50 -0500, "Jim" wrote: wrote in message . .. On Tue, 15 Jan 2008 17:07:42 -0800 (PST), wrote: On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Wavelength is usually stated as "Peak to Peak", or pp How is it calculated? It can be measured using an oscilloscope. I know how to measure amplitude or time with a scope. I just can't figure out how to measure distance. |
A question about radio, sound, "wave length" etc.
wrote in message ... On Jan 15, 8:51 pm, wrote: On Jan 15, 8:33 pm, JG2U wrote: On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." It's the distance, or "length", that the signal in question would travel while transitioning through a complete cycle. An audible signal will generally travel at the speed of sound, and light (different wavelengths, different colors) will travel at the speed of light. Does that help? HOWEVER, Sometimes a wave amplitude can be a length, for example a wave on the surface of water or a wave on the surface of a drum. Basically, these are special cases. Sorry, i forgot these obvious examples. The x-ray mirrors are seriously shiny but look like small cones with holes at both ends. They are made of metal (electroformed nickel) with an inner surface of gold. If you hold them up to the sun, they will concentrate the sunlight like a parabolic mirror would. I'll resist the urge to go on and on about how they work and bore you to death. NOW, could somebody please explain Hull Speed?- Hide quoted text - - Show quoted text - Hull speed is basically the maximum speed at which a displacement type hull can move through the water before climbing the bow wave and planing off... and the power & Sail Squadron teaches us that would be the square root of your water line x 1.34. For my old Sandpiper 565..that would be approx 4 x 1.34 = 5.36 knots |
A question about radio, sound, "wave length" etc.
wrote in message ... On Wed, 16 Jan 2008 10:33:17 -0500, "Eisboch" wrote: wrote in message . .. It can be measured using an oscilloscope. You can measure the amplitude and frequency. You'd have to calculate the wavelength. Eisboch I agree, although in my particular case, my scope will do that for me, along with a lot of other handy functions. New fangled devices. Last scope I saw was a big ass, dual trace Tektronics with Navy inventory stickers. Eisboch |
A question about radio, sound, "wave length" etc.
wrote in message ... On Wed, 16 Jan 2008 12:30:03 -0500, "Eisboch" wrote: wrote in message . .. On Wed, 16 Jan 2008 10:33:17 -0500, "Eisboch" wrote: wrote in message m... It can be measured using an oscilloscope. You can measure the amplitude and frequency. You'd have to calculate the wavelength. Eisboch I agree, although in my particular case, my scope will do that for me, along with a lot of other handy functions. New fangled devices. Last scope I saw was a big ass, dual trace Tektronics with Navy inventory stickers. Eisboch Yeah, mine even has a built in curve tracer (they call it a component tester) so I can examine the health of the p/n junctions in transistors. Who makes it? Eisboch |
A question about radio, sound, "wave length" etc.
"Gene Kearns" wrote in message ... On Wed, 16 Jan 2008 02:34:19 GMT, Short Wave Sportfishing penned the following well considered thoughts to the readers of rec.boats: |On Tue, 15 Jan 2008 16:50:09 -0800 (PST), Tim |wrote: | |OK, I picked this up on another board,a nd seeing that Eisboch, Tom, |Gene and Larry have had dealings with this stuff. I thought I'd |present it here. It has my curiosity up as well. | |Wavelength is the length measurement from the beginning to the end of |one full cycle. Or think of it another way, the distance a wave at a |given frequency to travel from 0 degrees to 360 degrees. | |Frequency is the number of wave periods passing a point in time and is |inversely proportional to wavelength - the higher the frequency of the |signal, the shorter the wavelength. Wavelength is the distance between repeating units of a propagating wave of a given frequency. SI units are used, where the wavelength is expressed in meters, the frequency in Hz, and the propagation velocity in meters per second. "Waveheight" is called "amplitude" and is the magnitude of the maximum disturbance in a medium during one wave cycle. The amplitude is not measured by time.... it is most likely measured by voltage. Hence, one is a measure of physical distance between repeating units (frequency) and the other is a measure of relative strength not measured in time. It is what you see on an oscilloscope. Time (distance) on the "X" axis and voltage on the "Y" axis. For further confusion, please see Time Domain Reflectometer..... -- Grady-White Gulfstream, out of Oak Island, NC. Homepage http://pamandgene.idleplay.net/ Rec.boats at Lee Yeaton's Bayguide http://www.thebayguide.com/rec.boats spectrum analyzer. |
A question about radio, sound, "wave length" etc.
"Eisboch" wrote in message ... "Jim" wrote in message ... wrote in message ... On Tue, 15 Jan 2008 17:07:42 -0800 (PST), wrote: On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Wavelength is usually stated as "Peak to Peak", or pp which is 180 degrees, right? ;- 360 degrees. Eisboch Actually is 180 degrees for a peak to peak on a sign wave. But for frequency, it is point to same point on the next wave. You could measure it anywhere on the wave. But Positive peak to Positive peak or Negative peak to Negative Peak or + or - zero crossing all work. Frequency = 1/ time. Wave length = speed of wave / frequency. This will work for sound at about 1126 ft/ second or 300 m/s for radio. |
A question about radio, sound, "wave length" etc.
On Wed, 16 Jan 2008 10:42:32 -0500, "Jim"
wrote: I know how to measure amplitude or time with a scope. I just can't figure out how to measure distance. You don't measure distance on the scope, it measures time. Given the speed of the wave, typically 300,000,000 meters/sec, it is easy to calculate distance, e.g., a 1 microsecond wave equals 300 meters wavelength. |
A question about radio, sound, "wave length" etc.
"Calif Bill" wrote in message ... "Eisboch" wrote in message ... "Jim" wrote in message ... wrote in message ... On Tue, 15 Jan 2008 17:07:42 -0800 (PST), wrote: On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Wavelength is usually stated as "Peak to Peak", or pp which is 180 degrees, right? ;- 360 degrees. Eisboch Actually is 180 degrees for a peak to peak on a sign wave. But for frequency, it is point to same point on the next wave. You could measure it anywhere on the wave. But Positive peak to Positive peak or Negative peak to Negative Peak or + or - zero crossing all work. 180 degrees positive peak to negative peak or negative peak to next positive peak. 360 degrees positive peak to positive peak or negative peak to negative peak, or as you say, any from any point to the next exact point on the sine wave. Eisboch |
A question about radio, sound, "wave length" etc.
On Wed, 16 Jan 2008 13:23:20 -0800, "Calif Bill"
wrote: "Eisboch" wrote in message m... "Jim" wrote in message ... wrote in message ... On Tue, 15 Jan 2008 17:07:42 -0800 (PST), wrote: On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Wavelength is usually stated as "Peak to Peak", or pp which is 180 degrees, right? ;- 360 degrees. Eisboch Actually is 180 degrees for a peak to peak on a sign wave. But for frequency, it is point to same point on the next wave. You could measure it anywhere on the wave. But Positive peak to Positive peak or Negative peak to Negative Peak or + or - zero crossing all work. Frequency = 1/ time. Wave length = speed of wave / frequency. This will work for sound at about 1126 ft/ second or 300 m/s for radio. The period of the function y = sin x, is 2pi or 360 degrees. The period can be measured peak to peak or in an infinite number of other ways.Perhaps I should have been more explicit. -- John H |
A question about radio, sound, "wave length" etc.
"Eisboch" wrote in message ... "Calif Bill" wrote in message ... "Eisboch" wrote in message ... "Jim" wrote in message ... wrote in message ... On Tue, 15 Jan 2008 17:07:42 -0800 (PST), wrote: On Jan 15, 7:50 pm, Tim wrote: OK, I picked this up on another board,a nd seeing that Eisboch, Tom, Gene and Larry have had dealings with this stuff. I thought I'd present it here. It has my curiosity up as well. I'm not up on physics, concerning this so here goes: "I searched the web but couldn't find an answer to a simple question which for my purposes is really a matter of curiosity. Of course, sometimes these kinds of questions end up teaching me the most. Most defintions of wavelength are along the lines of the distance between points of corresponding phase of two consecutive cycles of a wave. I'm not an idiot , so I understand what is a pretty straightforward definition. What I don't get is why the term length? I mean, they don't call the amplitude the waveheight. I kind of think of it as a wavegap. If you painted a big sine wave on the street and asked me how long it was, I'd get one of those little rolling doohickies for measuring and trace the line through its curve. Without knowing the definition in advance, I wouldn't think you would be asking me the straight distance between two points of corresponding phase. I ask this question because I don't understand why it's called what it's called, not because I want to tell the experts they got it wrong. It's bugged me for a while, so I've finally decided to take the plunge and risk looking stupid. Thanks in advance for any responses or links to read..." -- Jim Carr It is called "length" because it truly is a length. Wavelength is usually stated as "Peak to Peak", or pp which is 180 degrees, right? ;- 360 degrees. Eisboch Actually is 180 degrees for a peak to peak on a sign wave. But for frequency, it is point to same point on the next wave. You could measure it anywhere on the wave. But Positive peak to Positive peak or Negative peak to Negative Peak or + or - zero crossing all work. 180 degrees positive peak to negative peak or negative peak to next positive peak. 360 degrees positive peak to positive peak or negative peak to negative peak, or as you say, any from any point to the next exact point on the sine wave. Eisboch The definition of peak to peak must have changed since I was in A school. I was taught that positive peak to negative peak or negative peak to positive peak shal be called peak to peak. (Neener Neener) |
A question about radio, sound, "wave length" etc.
"Jim" wrote in message ... The definition of peak to peak must have changed since I was in A school. I was taught that positive peak to negative peak or negative peak to positive peak shal be called peak to peak. (Neener Neener) Sure. I don't disagree. Usually the term "peak to peak" relates to amplitude measurements. But, a positive peak to the next negative peak is 180 degrees if you are looking for frequency over a time period. A positive peak to the next positive peak is 360 degrees. Or negative to the next negative. Or any other point to the next repeating point on the waveform. Eisboch |
A question about radio, sound, "wave length" etc.
"Eisboch" wrote in message ... "Jim" wrote in message ... The definition of peak to peak must have changed since I was in A school. I was taught that positive peak to negative peak or negative peak to positive peak shal be called peak to peak. (Neener Neener) Sure. I don't disagree. Usually the term "peak to peak" relates to amplitude measurements. But, a positive peak to the next negative peak is 180 degrees if you are looking for frequency over a time period. A positive peak to the next positive peak is 360 degrees. Or negative to the next negative. Or any other point to the next repeating point on the waveform. Eisboch 360 degrees= 1 cycle is the description I was looking for. Quit trying to confuse me with facts. Check tonights Tampa news videos. |
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