Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E3B
E3B01E3B

Where is transequatorial propagation (TEP) most likely to occur?

Deep Dive: E3B01

The correct answer is A: Between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator. Where is transequatorial propagation (TEP) most likely to occur is between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator. TEP occurs over paths perpendicular to the geomagnetic equator at specific distances. For amateur radio operators, this is important for TEP operation. Understanding this helps when operating TEP.

Why Other Answers Are Wrong

Option B: Incorrect. Points 1,500-2,000 miles apart on geomagnetic equator isn't correct - TEP is 2,000-3,000 miles perpendicular to equator. 1,500-2,000 miles on equator is wrong. Option C: Incorrect. Points at each other's antipode isn't correct - TEP is 2,000-3,000 miles perpendicular to equator. Antipode is wrong. Option D: Incorrect. Through region where terminator crosses geographic equator isn't correct - TEP is 2,000-3,000 miles perpendicular to geomagnetic equator. Terminator crossing isn't the location.

Exam Tip

TEP location = between points 2,000-3,000 miles apart, path perpendicular to geomagnetic equator. Think 'T'EP = 'T'wo-'T'hree thousand miles, 'P'erpendicular. TEP occurs over paths perpendicular to geomagnetic equator at 2,000-3,000 miles. Not 1,500-2,000, not antipode, not terminator - just 2,000-3,000 miles perpendicular.

Memory Aid

TEP location = between points 2,000-3,000 miles apart, path perpendicular to geomagnetic equator. Think 'T'EP = '2'-'3' thousand miles, 'P'erpendicular. TEP occurs over paths perpendicular to geomagnetic equator at 2,000-3,000 miles. Important for TEP operation.

Real-World Example

Transequatorial propagation (TEP): It's most likely to occur between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator. For example, a path from Florida to Argentina (perpendicular to geomagnetic equator, about 2,500 miles) can support TEP. This is where TEP occurs - 2,000-3,000 miles perpendicular to geomagnetic equator.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E3B

Reference: 2024-2028 Question Pool · E3 - Radio Wave Propagation

Key Concepts

Transequatorial propagation TEP 2,000 to 3,000 miles Perpendicular to geomagnetic equator

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E3B topic.