Here's a quick update on my build.Sorry I haven't posted much. Too little free time - I can barely keep up with reading the posts here. It is great to see so much activity!The test platform setup I've worked towards is a hanging torsion pendulum.See Wikipedia - Torsion Balance for a reasonable explanation. (Probably better web pages out there)I used a strong thin line to hang the apparatus (yellow in pics), which has a very low torsion spring constant, but unfortunately I still had to power the thing, so I also had to run an AC power line. I broke out the AC into stranded 14ga wire (black,white,green) and ran it close to the center to reduce its torsion effect as much as possible. This actually worked pretty well for a quick and easy solution.While I haven't measured/calculated the relevant variables for its harmonic oscillations (spring contant, moment of intertia), I did experiment with the setup enough to understand how well it would apply to small force measurements.The pendulum was very immune to small transient pertubations (air currents, vibrations, etc.) due to the reasonably large moment of intertia. This is a good thing to eliminate noise, but at first thought, not so great for measuring tiny forces. However, since the spring constant (k) is very small, there is very little counter-force when the pendulum has moved through a small but detectable angle (eg. 5 degrees). This means that an Impulse (Force x time) can be observed/measured despite its small force, if it is applied for enough time.So, in testing the setup using a weight set and pulley (shown), I observed that a 1g weight (10mN) quickly accellerated the pendulum, (motion was obvious within a second). A 100mg weight (1mN) applied for 10 seconds had obvious motion. And a 50mg weight (500uN) would eventually show motion (20 seconds). (I didn't test anything smaller at this time). These observations are on the conservative side (motion is visibly obvious at the pendulum). For frustum testing, a laser mounted on the beam, projecting radially outward from the center gives a simple and more accurate rotation measurement. Also, I have not yet experimented with a longer balance beam to detect smaller forces.(As an aside for the non-physics folks, if there are any here - for a rotating system it is Torque that is relevant. Torque is the component of the force perpendicular to the beam multiplied by the distance to the center. Having the emdrive far from the center increases the torque for a given force.)The initial frustum has been built to the dimensions Shell suggested. I went with aluminum on this first build as it was a lot cheaper and I would worry less if I screwed something up! The magnetron is directly injected, currently positioned in the center of the sidewall for lack of a better guess. The mounting plate has been prepared to try other positions along the side.I have not done any tuning or resonance measurements of the cavity. (Currently lacking equipment to perform such tests). But I couldn't resist firing the thing up anyway.A few executions of 10-15 seconds each show ZERO motion. Naturally, I would've loved if the thing started spinning like a propellor, but I didn't exactly expect that. What I WAS happy with, was that the test platform showed its immunity to air currents, heating effects, (noise) at least for this first real test. (Forgot to mention, this test used the laser pointer projecting 6m away, and it stayed perfectly still for the tests).Note, as others have mentioned, a rotating test setup will be trouble if you have moving mass in your rig. For instance, if you were pumping cooling fluid around, even in a closed system, the fluid flow will likely have changing angular momentum, and this setup will obey the law of conservation of angular momentum by rotating! We aren't trying to break that one yet too, are we?Some material details if interested:- Hanging support line - dacron fishing tow line - 135lb test- Base beam - 3/4" plywood - 200cm x 24cm- Aluminum (3003H14) frustum- 26.6cm inner plate spacing (cone .032")- 16.0cm diam small endplate .032"- 28.0cm diam large endplate .050"Anyway, that's where I'm at. I wanted to share, especially the test setup, since it seemed like there may be even more DIY projects in the works. I felt this setup was quite easy and cost effective to construct, eliminated the thermal lift issue, and had the ability to measure reasonably small forces.If motion ever is detected, it's easy to do re-orientation tests (north,east,south,west), and it can be extended with boxing-in the frustum section (eg. plexiglass) to further reduce heated air current effects.