Coupling of Very Low Frequency Through-the-earth Radio Signals to Elongated Conductors
Bibliographic record
Abstract
Through-the-earth (TTE) radio signals (400-9000 Hz) have been observed to couple to elongated conductors present near the transmitter (Tx). This phenomenon, which greatly increases signal range, is poorly understood. Experimental and numerical data are combined to better understand the potential of such a communication link. A finite-difference time-domain (FDTD) code is used with a thin wire approximation to model the elongated conductors, which include railway tracks and an elevator shaft. The coupling effect, attributed to currents induced in the elongated conductor, is characterized based on measurements of the three magnetic field components in the vicinity of the conductors. The ability of FDTD to handle arbitrary material geometries makes it an effective tool not only for reconciling theoretical and experimental results, but also for predicting the viability of TTE communication links in different settings, and to optimize the placement of the Tx and receiver.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".