---
kind: "section"
citation: "47 C.F.R. § 73.160"
title: "47"
number: "73.160"
heading: "Vertical plane radiation characteristics, f(θ)."
url: "https://uscodex.org/cfr/47/73.160"
---

# §73.160. Vertical plane radiation characteristics, f(θ).

- (a) The vertical plane radiation characteristics show the relative field being radiated at a given vertical angle, with respect to the horizontal plane. The vertical angle, represented as θ, is 0 degrees in the horizontal plane, and 90 degrees when perpendicular to the horizontal plane. The vertical plane radiation characteristic is referred to as f(θ). The generic formula for f(θ) is:
- (b) **Listed below are formulas for f(θ) for several common towers.**
  - (1) For a typical tower, which is not top-loaded or sectionalized, the following formula shall be used:
  - (2) For a top-loaded tower, the following formula shall be used:

    See Figure 1 of this section.

  - (3) For a sectionalized tower, the following formula shall be used:

    See Figure 2 of this section.

- (c) One of the above f(θ) formulas must be used in computing radiation in the vertical plane, unless the applicant submits a special formula for a particular type of antenna. If a special formula is submitted, it must be accompanied by a complete derivation and sample calculations. Submission of values for f(θ) only in a tabular or graphical format (i.e., without a formula) is not acceptable.
- (d) **Following are sample calculations.** (The number of significant figures shown here should not be interpreted as a limitation on the number of significant figures used in actual calculations.)
  - (1) For a typical tower, as described in [paragraph (b)(1)](#b-1) of this section, assume that G = 120 electrical degrees:
  - (2) For a top-loaded tower, as described in [paragraph (b)(2)](#b-2) of this section, assume A = 120 electrical degrees, B = 20 electrical degrees, and G = 140 electrical degrees, (120 + 20):
  - (3) For a sectionalized tower, as described in [paragraph (b)(3)](#b-3) of this section, assume A = 120 electrical degrees, B = 20 electrical degrees, C = 220 electrical degrees, D = 15 electrical degrees, G = 140 electrical degrees (120 + 20), H = 235 electrical degrees (220 + 15), and Δ = 115 electrical degrees (235−120):

## Notes

### Amendments

[46 FR 11993, Feb. 12, 1981]

### Authority

Authority: 47 U.S.C. 154, 155, 301, 303, 307, 309, 310, 334, 336, 339.

### Amendments

[46 FR 11993, Feb. 12, 1981]