gin&pez@arg
Let me start by first informing you that I have successfully ran your BBC Basic Program, seeded with the raw data from my NanoVNA; and your program yields results that are consistent with the "corrected" results of my NanoVNA. This test was conducted using a 7 foot (2.134 m) length of RG-58 coaxial cable terminated in a 3.3 ohm carbon film resistor as the DUT (g in your program). The test was performed at a frequency range of 1 to 6 MHz in 50 KHz steps to minimize test hardware parasitic influences from contaminating the calculations. I am now satisfied that I am following your work. I must inform you however; that you haven't made this an easy exercise FACUPOV. :-)
The tasks performed today required that I download and install Putty; identify, download, and install an appropriate version of the NanoVNA software for which the Console Command File is valid; perform the 4 required scans; port the results of each scan into a spreadsheet; perform the compact formula () calculations; plot the results; hypothesize the results were incomplete; Install the BBC BASIC Interpreter; load your BASIC source listing; load in sample data from my scan results; verify the results were in agreement with my corrected NanoVNA measurements; load in another sample data set from my scan results to confirm the first results were not a consequence of serendipity; compare your compact formula with the BBC BASIC source listing to ascertain where they failed to be in agreement; and finally discover that the compact formula is only a subset of your overall solution.
FACUPOV, the journey to this point has not been FACUPOV.
The exercises performed today further confirms that your BBC BASIC program could (should) be readily expanded to:
1) read the 4 appropriately named measurement files, or optionally, read a single file of the three SOL measurements, and an independent file of DUT measurements and;
2) output a computed results file of length equal to the number of data points provided at the input.
As an interim personal aid, my spreadsheet version is far enough along to be worth expanding to include the remainder of your equations and this will satisfy my near term need.
I first attempted to perform today's tasks by entering your compact formula () into a spreadsheet in an effort to verify my understanding of your project. This effort was unsuccessful until I compared it to the BBC BASIC source listing. That effort led me to the discovery that the compact formula is in agreement with the BBC BASIC source, but an incomplete solution overall. A closer look at the BBC BASIC source reveals that I have yet to confirm the full set of equations published previously, corrected by the now revised compact formula ().
To verify the BBC BASIC source, required that I painfully entered individual test data points at the frequency endpoints of my NanoVNA measurements, then perform a calibration and sweep of my DUT on my NanoVNA to facilitate comparing the corrected measurements. Of course; I am not about to do this for all 101 data points and plot the results across any significant bandwidth.
With the above effort expended, I believe I am now able to reproduce your work to this point; but I am only beginning to acquire the tools needed to try understanding it. This is forward progress however; and the results look encouraging so far.
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73
Gary, N3GO
