---
kind: "section"
citation: "47 C.F.R. § 80.767"
title: "47"
number: "80.767"
heading: "Propagation curve."
url: "https://uscodex.org/cfr/47/80.767"
---

# §80.767. Propagation curve.


The propagation graph, § 80.767 Graph 1, must be used in computing the service area contour. The graph provides data for field strengths in dBu for an effective radiated power of 1 kW, over sea water, fresh water or land (smooth earth); transmitting antena heights of 4,800, 3,200, 1,600, 800, 400, 200, and 100 feet; based on a receiving antenna height of 9 meters (30 feet), for the 156-162 MHz band. The use of this is described in this section.

- (a) Calculate the effective radiated power of the coast station, Ps in dB referred to 1 kW (dBk), as follows:
- (b) **Determine the antenna height.** For antenna heights between the heights for which this graph is drawn, use linear interpolation; assume linear height-gain for antennas higher than 4,800 feet.
- (c) For receiver antenna heights lower than 9 meters (30 feet), assume that the field strength is the same as at 9 meters (30 feet).
- (d) **Assume that propagation over fresh water or over land is the same as that over sea water.**

## Notes

### Authority

Authority: 47 U.S.C. 151-155, 301-609; 3 U.S.T. 3450, 3 U.S.T. 4726, 12 U.S.T. 2377.

### Source

Source: 51 FR 31213, Sept. 2, 1986, unless otherwise noted.