Talk:Two-ray ground-reflection model

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Variable undefined.[edit]

"Ground Reflection $\Gamma (\theta )={\frac {sin\theta -X}{sin\theta +X}}$

where $X_{v}=$ ${\sqrt {\varepsilon _{g}-{cos}^{2}\theta }} \over {\varepsilon _{g}}$

X_{h}={\sqrt {\varepsilon _{g}-{cos}^{2}\theta }}

"

X

(with no subscript) is never defined. I'm guessing one of the values given is for the horizontally polarised case and the other for the vertically polarised case but nowhere is this spelt out. Furthermore

\varepsilon _{g}

is never defined. Plugwash (talk) 13:39, 9 April 2014 (UTC)[reply]

X_{v}

is the vertically polarised component of the reflection and

X_{h}

is the horizontally polarised component.

\varepsilon _{g}

is the relative permittivity of the ground. This was all in the original text I'm afraid. My edits just made the derivation work; I haven't gone back and corrected or improved some of the basic equations, or specified the missing variables. Any help on this is much appreciated! Derekjc (talk) 10:14, 27 July 2016 (UTC)[reply]

Also

G_{g}r

and

G_{l}os

don't seem to be defined anywhere. Plugwash (talk) 13:57, 9 April 2014 (UTC)[reply]

G_{*}

is the antenna gain. As far as I understand Rappaport it's not so much a matter of

G_{los}

G_{gr}

, but rather

G_{t}

(transmitter)

G_{r}

(receiver). @Plugwash: Should we just fix this? Currently it's rather wrong. CMorty (talk) 10:57, 24 March 2015 (UTC)[reply]

G_{los}

is the gain of the antennas (combined transmitter and receiver gains) in the direction of the line-of-sight (LOS) path and

G_{gr}

is the combined antenna gains in the direction of the ground reflection (GR) path. Eventually we assume for the long distances (relative to antenna mast heights above the ground) the gains are approximately equal, therefore,

G_{los}\approx G_{gr}\approx G

. Derekjc (talk) 09:58, 27 July 2016 (UTC)[reply]

mathematical derivation[edit]

Mathematical derivation does not appear exactly in Rappaport's or Jake's reference even though it is referred. Could someone please give the correct reference for mathematical derivation? — Preceding unsigned comment added by 125.168.4.243 (talk) 04:15, 14 June 2018 (UTC)[reply]

Ground properties[edit]

It might be a great idea to also write about how the material the surface at the reflection point is made of will affect the formula. 2003:CA:9F0C:70F4:C0BB:6DEA:A5D6:EA63 (talk) 20:49, 19 November 2021 (UTC)[reply]