Methods of suppressing sky-wave radiation from vertical antennas over imperfect ground
Bibliographic record
Abstract
Ground wave radar (GWR) employs a ground wave mode in the detection of ships and icebergs. Reflected radar signals from the ionosphere can interfere with the principal ground wave mode. If the field strength of the ground wave is less than that of the ionospheric reflected wave, the range of the radar may be limited to the height of the ionospheric layer. This reduces the radar's maximum detection range. GWR antennas must be able to minimize both transmission and/or reception of signal levels in the vertical and near vertical directions. Radiation patterns of vertically polarized antennas create a null in the vertical direction which suits the applications of GWR. It is well known that increases in maximum gain and reduction in half power beam width in the radiation pattern of a test vertical whip monopole are possible by modifying the geometry. The present work compares radiation characteristics of a number of geometrical modifications to the test whip monopole. These modifications include variation of the monopole length and its height over ground as well as the size of the ground wire grid. The data are calculated using the numerical electromagnetics code (NEC-2) which is based on the moment method. The feasibility of achieving a custom design antenna for GWR applications is illustrated.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.001 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".