Hi Robin, I was confused by this also. I don't think english is Andres first language, so his paper is a little obtuse at points. What he's saying, after a more careful read on my part, is that he assumes "The Energy of a wave is transported at its phase velocity". is what Roger is claiming. I haven't had time to check the math, but having now at least read Rogers theory paper, I have my doubts about Andres assumption.
Look at section 2.2 for example. Roger diagrams the path of a TEM wave inside the microwave cavity. This is the correct model, I have measured this same behavior in a real cavity with real probes, as I had described earlier ( on the Vo. list even, check the archives ). He then goes on to say something like, "if we measure the group velocity by using the axial distance, rather than the true path, we see that group velocity can be much slower at the short end of the tube than the longer ( as in 2.4 )". I will add to that statement by saying that in addition, phase velocity will grow faster by the same amount. In the limit condition, phase velocity will be infinite, and group velocity will be zero. I think Roger has a pretty good handle on the mechanics of what is going on in the wave guide, based on the text at least. What I find a little questionable about Rogers idea is that the system is truly open. Look at the gedanken experiment in fig 2.1. If plate R1 and R2 are physically connected, there ought to be net motion in the direction of F1. That seems OK to me. But how about if the transmitter Tx is connected to the same frame? Now I wonder... but that's basically Rogers claim. K. -----Original Message----- From: Robin van Spaandonk [mailto:[EMAIL PROTECTED] Sent: Monday, September 25, 2006 11:57 PM To: [email protected] Subject: Re: [Vo]: stationary emdrive- inertial anchor In reply to Remi Cornwall's message of Mon, 25 Sep 2006 20:21:56 +0100: Hi Remi, [snip] >Don, > >I had a few thoughts on the paper: >http://uk.geocities.com/remicornwall/ElectromagneticPropulsion.htm In http://uk.geocities.com/remicornwall/FeynmanIIpg24a7sections24a2to24a4.jpg it states very explicitly: "The group velocity of the waves is also the speed at which energy is transported along the guide". Which is what I always thought it was. However Andreas Rathke states in his paper "The Energy of a wave is transported at its phase velocity". (See page 1). One of them seems to be wrong. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
