Wasn't that how Shawyer got the idea, only from a satellite not a ship?
If I understood correctly some things in this thread, EM radiations heat the frustum, which changes its shape, which changes the resonant frequency of the cavity, so it's difficult to keep the EM source tuned.Would cooling (with flowing water for example) the copper plates 1) reduce the variation of the resonant frequency, by reducing the variation of temperature, thus reducing the geometrical changes of the frustum 2) not interfere with the thrust produced ?
Or a phase locked loop circuit. http://en.m.wikipedia.org/wiki/Phase-locked_loop#Frequency_synthesis
Quote from: Mulletron on 02/18/2015 02:45 pmOr a phase locked loop circuit. http://en.m.wikipedia.org/wiki/Phase-locked_loop#Frequency_synthesisHow would apply this to tracking the resonant freq of the cavity to the input freq of the loop antenna?
A feedback circuit would be required in order to keep the VCO on the resonant frequency. If such a feedback is possible then a simple MCU could be programmed to do that using an ADC as output, it would not be a PLL anyway but more similar to an FLL.
Quote from: Giovanni DS on 02/18/2015 03:06 pmA feedback circuit would be required in order to keep the VCO on the resonant frequency. If such a feedback is possible then a simple MCU could be programmed to do that using an ADC as output, it would not be a PLL anyway but more similar to an FLL.Where does the feedback signal come from?
Quote from: SleeperService on 02/18/2015 03:09 pmQuote from: Giovanni DS on 02/18/2015 03:06 pmA feedback circuit would be required in order to keep the VCO on the resonant frequency. If such a feedback is possible then a simple MCU could be programmed to do that using an ADC as output, it would not be a PLL anyway but more similar to an FLL.Where does the feedback signal come from?This is the problem I do understand controls and realtime systems but microwaves and resonant cavities are not my field. How do you know it is resonating?In theory the thrust could be your feedback, you tune the VCO in order to maximize that.
Resonant cavities are also filters. You monitor a sample port to ensure the cavity is resonant at the desired frequency. Another control loop compensating for doppler drift is needed. Shawyer mentions this type of control loop over at emdrive.com.