Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-23T10:43:08.138Z Has data issue: false hasContentIssue false

On the Attenuation of Wireless Signals in Short Distance Overland Transmission

Published online by Cambridge University Press:  24 October 2008

Extract

1. It is pointed out that the signal strength of a wireless wave at a distant point depends on:

(a) the electrical constants of the ground,

(b) the curvature of the earth,

(c) the existence of an “atmospheric” ray coming downwards from the Heaviside layer.

2. We can eliminate the effect of (b) and (c), and so obtain direct evidence about the electrical constants of the ground, by making measurements near the transmitter.

3. Measurements on wave lengths of 300 m. and upwards give information about the resistivity of the ground, and on shorter wave lengths (15 m.) give the dielectric constant of the ground.

4. Attenuation measurements have been made over short distances for wave lengths of 1600 m. and 360 m.

5. The results are compared with those calculated from Sommerfeld's theory and show close correlation for distances beyond 10 wave lengths, but show deviations from the theory for shorter distances.

They give as values for the resistivity of the ground

p = 1·8 × 1013 E.M.U.

for the Daventry signals, and

p = 0·6 × 1013 E.M.U.

for the London signals.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1926

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

* Appleton, , Proc. Phys. Soc. vol. xxxvii, Part 2 (Feb. 1925)Google Scholar; Appleton, and Barnett, , Nature (03 7, 1925)Google Scholar; Electrician, p. 398 (04 3, 1925)Google Scholar; Proc. Camb. Phil. S. vol. xxii, Part 5, p. 674Google Scholar; Proc. Roy. Soc. A, vol. cix, p. 621.Google Scholar

* Love, , Phil. Trans. A, vol. ccxv, p. 105 (1905)Google Scholar, a complete bibliography up to 1915 will be found in this paper; Watson, G. N., Proc. Roy. Soc. A, vol. xcv, p. 83 (1918) and p. 546 (1919)CrossRefGoogle Scholar; der Pol, Van, Phil. Mag. vol. xxxviii, p. 365 (1919).CrossRefGoogle Scholar

* Journ. Inst. of Electr. Eng. vol. xxxv, p. 321 (1905)Google Scholar; Electrician, vol. LV, p. 409 (1905).Google Scholar

* Proc. Inst. Rod. Eng. (Jan. 16, 1924).Google Scholar

* Ann. der Phys. voL xxii, p. 846 (1907).Google Scholar

* Ann. der Phys. vol. xxviii, p. 665 (1909)Google Scholar; Jahrbuch der drahtlosen Telegraphic und Telephonie, vol. iv, p. 157 (1910).Google Scholar

* De Ingenieur, No. 38 (1925).Google Scholar

Smith-Rose, and Barfield, , Experimental Wireless, p. 737 (09 1925)Google Scholar; Proc. Roy. Soc. A, vol. cvii, p. 587.Google Scholar

Zenneok, , Ann. der Phys. vol. xxiii, p. 859 (1907).Google Scholar

* Bull, of the Bureau of Standards, vol. vii, No. 3.Google Scholar

Electrician, p. 154 (05 7, 1915).Google Scholar

Journ. Inst. Eleclr. Eng. vol. LXIII, p. 977 (1925).Google Scholar

§ Proc. Roy. Soc. A, vol. cix, p. 367.Google Scholar

* Proc. Inst. Electr. Eng. vol. Lxiii, p. 597 (1925).Google Scholar

* Macdonald, , Proc. Roy. Soc. A, vol. cviii (1925).Google Scholar

Exp. Wireless, p. 745 (Sept. 1925).Google Scholar

* Appleton, and Barnett, , Proc. Roy. Soc. A, vol. cix.Google Scholar