@Poynt99 What would you suggest to obtain the maximum amplitude of magnetic flux variations in the core (max. ΔΦ or max. Δ ampturns) at the target frequency of 45.525MHz from the current provided by the Tracking Generator in Itsu's Spectrum Analyzer ?
I have not been following, so I'm going to make a couple suggestions based on my limited knowledge of NMR, the apparent goal, and what has been done so far (I did go back to read the threads and watch Itsu's videos). If the following is idiotic, don't be too harsh on me Since Itsu is now using a transformer, and since a parallel LC tank will maximize current at resonance, and current (amp-turns) is what is required to vary core flux, I would suggest trying to tune either the primary alone (TG side), or both sides, to the target frequency. I would suggest trying to utilize an adjustable air capacitor, but you may need to increase your no. of turns (increase L) to get in range and achieve 45.5MHz resonance. As shown in Itsu's videos, external parasitic capacitance is messing with the existing tuning (existing in the sense that inter-winding capacitance, inductance, and possibly leakage inductance is contributing), and as such I would suggest that the apparatus be placed in an electrostatic shield. The particular construction of RF duplexer filters (which contain variable capacitors and inductors) is a testament to the importance of electrostatic shielding at these frequencies (see pic). Another suggestion for your experiment would be to dispense with the ceramic magnets and instead combine a DC source and the TG source such that you can manipulate the static magnetic field in a controlled manner (whilst shielded within the electrostatic shield). I would apply the DC source to both the primary and secondary. Isolation between the DC source and the TG/SA output/input could be achieved by capacitive coupling to/from the TG/SA, and inductive coupling of the DC source. Wouldn't the maximum energy transfer from the TG to the core manifest itself as a peak on the display?
I would think so, but I don't know what "happens" to the core if/when it reaches NMR.
« Last Edit: 2019-01-22, 02:25:25 by poynt99 »
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