On Jan 16, 9:17 pm, "Jim" wrote:
"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.

OK, for radio waves, there are several straightforward ways to
directly measure wavelength instead of calculating it from frequency.
The easiest is with a waveguide with a variable end. This is simply a
metal tube whose diameter is roughly the wavelength. You adjust the
length of the tube (it should have a sliding metal end) till a
electric field prob in the center measures a maximum indicating that
your wave terminates at the end. Then you move he slide in and you
will find another position where you have a maximum. The distance you
have moved the slide is the wavelngth. The electrical engineers here
can tell you how this relates to SWR etc and all about Smith Charts
but this is a very straightforward physical measurement.
You can also use two vertical antennas each emitting a sin wave of
exactly identical in phase signal. When the two antennas are exactly
one half wavelength apart, you will see a maximum signal along a line
that passes exactly betwen the two antennas.
For visible light, one uses a device called an interferometer to
directly measure the wavelngth. Because such devices are so sensitive
to movement, they are often used to align extremely precise equipment.
For x-rays, one uses crystals where the wavlength is given by
wavelength=2dsin(q) where 2d is the crystal spacing and q is the
reflection angle (I do this every day)
For sound waves, I would use a tube with a variable slider so the tube
would resonate with teh applied sound when the slider is set to the
correct length corresponding to the wavelngth.

wrote in message
...
On Wed, 16 Jan 2008 13:23:20 -0800, "Calif Bill"

wrote:


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.


What's the matter Bill? Didn't the website you Googled know how to spell
sine?

Bwhahahahahahaha!



Me bad. Especially for misspelling sine. I know all that stuff. My degree
is in Electronic engineering. As well as the fact I worked on repairing
Radar and Instrument landing systems and nav aids in the Air force. As
well as part of my patent includes Sine Square + Cosine Square = 1.

If I had googled it, I would have spelt Sine correctly.

"Jim" wrote in message
...

"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.

Actually may not be 360 degrees. What if it is a square wave?

wrote in message
...
On Jan 16, 9:17 pm, "Jim" wrote:
"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.

OK, for radio waves, there are several straightforward ways to
directly measure wavelength instead of calculating it from frequency.
The easiest is with a waveguide with a variable end. This is simply a
metal tube whose diameter is roughly the wavelength. You adjust the
length of the tube (it should have a sliding metal end) till a
electric field prob in the center measures a maximum indicating that
your wave terminates at the end. Then you move he slide in and you
will find another position where you have a maximum. The distance you
have moved the slide is the wavelngth. The electrical engineers here
can tell you how this relates to SWR etc and all about Smith Charts
but this is a very straightforward physical measurement.
You can also use two vertical antennas each emitting a sin wave of
exactly identical in phase signal. When the two antennas are exactly
one half wavelength apart, you will see a maximum signal along a line
that passes exactly betwen the two antennas.
For visible light, one uses a device called an interferometer to
directly measure the wavelngth. Because such devices are so sensitive
to movement, they are often used to align extremely precise equipment.
For x-rays, one uses crystals where the wavlength is given by
wavelength=2dsin(q) where 2d is the crystal spacing and q is the
reflection angle (I do this every day)
For sound waves, I would use a tube with a variable slider so the tube
would resonate with teh applied sound when the slider is set to the
correct length corresponding to the wavelngth.

Similar to how a CD works. The distance from the laser to the reflective
backing is very close to the wave length. So when it reflects back to the
detector you get a dark spot.

"John H." wrote in message
...
On Wed, 16 Jan 2008 06:52:36 -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


which is 180 degrees, right? ;-

For a sine wave, 2 pies (apple?), or 360 degrees.
--
John H

what if it is not a sine wave?

"CalifBill" wrote in message
...

"Jim" wrote in message
...

"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.

Actually may not be 360 degrees. What if it is a square wave?


You mean like a pulse train with unequal pulse lengths?

I don't know.

Eisboch

On Wed, 16 Jan 2008 19:05:01 -0800 (PST),
wrote:

On Jan 16, 9:17 pm, "Jim" wrote:
"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.

OK, for radio waves, there are several straightforward ways to
directly measure wavelength instead of calculating it from frequency.
The easiest is with a waveguide with a variable end. This is simply a
metal tube whose diameter is roughly the wavelength. You adjust the
length of the tube (it should have a sliding metal end) till a
electric field prob in the center measures a maximum indicating that
your wave terminates at the end. Then you move he slide in and you
will find another position where you have a maximum. The distance you
have moved the slide is the wavelngth. The electrical engineers here
can tell you how this relates to SWR etc and all about Smith Charts
but this is a very straightforward physical measurement.
You can also use two vertical antennas each emitting a sin wave of
exactly identical in phase signal. When the two antennas are exactly
one half wavelength apart, you will see a maximum signal along a line
that passes exactly betwen the two antennas.
For visible light, one uses a device called an interferometer to
directly measure the wavelngth. Because such devices are so sensitive
to movement, they are often used to align extremely precise equipment.
For x-rays, one uses crystals where the wavlength is given by
wavelength=2dsin(q) where 2d is the crystal spacing and q is the
reflection angle (I do this every day)
For sound waves, I would use a tube with a variable slider so the tube
would resonate with teh applied sound when the slider is set to the
correct length corresponding to the wavelngth.

No offense, but it's a hell of a lot easier to determine wavelength
for a specific RF frequency (or any frequency for that matter) using
simple arithmetic.

To each his own though.

On Wed, 16 Jan 2008 21:44:04 -0800, "CalifBill"
wrote:


"Jim" wrote in message
.. .

"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.

Actually may not be 360 degrees. What if it is a square wave?

The same way.

On Thu, 17 Jan 2008 02:27:04 -0500, "Eisboch" wrote:


"CalifBill" wrote in message
...

"Jim" wrote in message
...

"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.

Actually may not be 360 degrees. What if it is a square wave?

You mean like a pulse train with unequal pulse lengths?

I don't know.

Thanks.

Now I have to go dig out the books. :)

"CalifBill" wrote in message
...

"Jim" wrote in message
...

"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.

Actually may not be 360 degrees. What if it is a square wave?

In that case you would probably be talking PRR. This discussion is starting
to get over my head so I'll bow out and let you engineers have at it.