[RTTY] About N4II's experiment...

[Kok Chen]

On Mar 14, 2014, at 8:49 PM, Kai wrote:

> We do however want to measure the propagation speed of signals in the ionosphere...

There are more unknowns than measurables, Kai, if all you are measuring is the path transit time.  The problem is not the "baud rate" (we know for example that it is easy to measure transit time to much more precise than T, using a pulse whose width is T).

Think of a similar experiment where you use total internal reflection of a prism in a reflex light path to measure the speed of a laser beam.  You don't know the size of the prism, nor the distance of the laser to the prism, and you don't know the refractive index of the glass used to construct the prism.  All you can do is to measure the transit time as precisely as possible.  With that alone, you cannot determine the refractive index of the prism. 

Now imagine the prism to be a simple model of the ionosphere.  (In the case of the ionosphere, the density is not even constant.)

73
Chen, W7AY