Hey, I just did one of those back-of-the envelope type calculations, to see if I could explain the thrust they are seeing for this so-called EmDrive.

I am using the fact that the Tesla has the dimensions N*s / C*m where N is Newton, s second,

C coulomb, m meter.

Force = I L T, where I is current in coulombs/second and L is length in meters. T is Tesla as defined above.

You can check to see that the result in Newtons is dimensionally correct as all units cancel except Newton.

For the value of I, I note that they are driving a loop antenna with 1 Kw of power ( maybe they use more Power than that ) but they are getting a resulting force of ~ 0.001 N / 1KW. So, I will use 1 KW going into a 50 Ohm loop antenna. So, I = ( P/R )^1/2 = ~ 5 Amps approximate value.

For L, I guesstimate the loop antenna and feed in as 2 meters. It could be more or less.

For T, I am going to use an upper value of the earth’s magnetic field B on the surface of ~ 65 uT.

So, Force in Newtons = 5 C/s * 2 m * 65 E-6 N*s / C*m = **0.00065 N**

That is **65%** of the thrust force they measured!

I think that is significant. What I think happens when they energize this thing it deflects like a compass needle. If it is capable of measuring forces on the order of 0.001 N, it must not take much too Force to make it deflect. The earths magnetic field is enough, with the power and current they are using.

What do you all think? Should we tell them?