Scope and limits

ABSTRACT ONLY. The full text is closed access with no legitimate open copy anywhere, confirmed by Unpaywall returning is_oa false with zero locations across 24 attempted routes. The abstract gives C_F ~ 1 and C_E ~ 1 without their functional form. The OSTI transcription's milliwatt prefix on the F-region coefficient is a transcription error: the published abstract prints microwatts (read on the publisher's page 2026-09-20), so the apparent thousandfold disagreement with the Duncan form recorded at the second reading is closed; the E-region coefficient is 1 mW/m2 in both. No explicit numerical bound on the frequency to plasma frequency ratio is stated. That Perkins and Goldman 1981 themselves state these results, as the claim first put it, is not checkable in the archive, which holds the abstract and not the paper: the full text was sought 2026-09-02 across the routes above and not obtained (claim narrowed 2026-09-20 to the abstract).