Mention was made, above, of panel resonance frequencies. By driving the amplifier with a sine wave signal generator, the frequency was swept over the range of interest. On thin panels a light object, like a screw washer, will dance with panel resonance. Massive objects, such as the simulated battery, will not respond as well and required another method. This time we used an old ceramic microphone element attached to the 'battery' and to observe the output signal on an oscilloscope.
Resonance frequencies are readily observable with such simple instrumentation.
Although hollow, the conical adaptor does not provide sufficient space to house Phase 3D, or any other reasonably sized payload. Thus, they require that our cylindrical section must be able to support the launch loads of this prime payload fellow passenger. Construction of two of these SBS units has been completed in Utah, mainly at Weber State University. These were made from the highest quality of ring-forged aircraft aluminum. The 4mm thick sheet aluminum rolled shell sections are attached to the Frames with a total of 976 special fasteners.