G8B05: Intermodulation products are closest to the original signal frequencies

Q: Which intermodulation products are closest to the original signal frequencies?

The correct answer is C: Odd-order. The correct answer is C: Odd-order. The intermodulation products that are closest to the original signal frequencies are odd-order. Odd-order products (3rd, 5th, etc.) are closer to the original frequencies than even-order products. For amateur radio operators, this is important for interference analysis. Understanding this helps when troubleshooting intermodulation.

Updated: Dec 9, 2025 | Source: 2023-2027 Question Pool | Topic: G8B

G8B05G8B

Which intermodulation products are closest to the original signal frequencies?

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Deep Dive: G8B05

The correct answer is C: Odd-order. The intermodulation products that are closest to the original signal frequencies are odd-order. Odd-order products (3rd, 5th, etc.) are closer to the original frequencies than even-order products. For amateur radio operators, this is important for interference analysis. Understanding this helps when troubleshooting intermodulation.

Why Other Answers Are Wrong

Option A (Second harmonics): Incorrect. Second harmonics are 2× the frequency, not intermodulation products - IMD products are combinations like 2F1-F2. Second harmonics are different. Option B (Even-order): Incorrect. Even-order products (2F1-F2, 2F2-F1) are further from original frequencies than odd-order - odd-order (3F1-2F2, etc.) are closer. Even-order isn't closest. Option D (Intercept point): Incorrect. Intercept point is a measurement parameter, not a type of product - it's used to characterize IMD, not a product type. Intercept point is different.

Exam Tip

IMD products closest to original = odd-order. Think 'O'dd-order = 'O'ccurs 'C'lose to original. Odd-order products (3rd, 5th, etc.) are closer to original frequencies than even-order. Not second harmonics, not even-order, not intercept point - just odd-order.

Memory Aid

IMD products closest to original = odd-order. Think 'O'dd-order = 'O'ccurs 'C'lose. Odd-order products (3rd, 5th, etc.) are closer to original frequencies than even-order. Most problematic IMD products.

Real-World Example

Two signals F1 and F2: Odd-order products like 3F1-2F2 and 2F1-F2 are closer to F1 and F2 than even-order products. For example, if F1=14.2 MHz and F2=14.3 MHz, odd-order products are closer to these frequencies than even-order. Odd-order IMD products are the most problematic because they're closest to the desired signals.

Source & Coverage

Question Pool: 2023-2027 Question Pool

Subelement: G8B

Reference: 2023-2027 Question Pool · G8 - Signals and Emissions

Key Concepts

Intermodulation products Odd-order Closest to original IMD products

Verified Content

Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G8B topic.