Antenna Noise Factor from Equivalent Noise Temperature: At 27 °C (T0 ≈ 290 K), an antenna has equivalent noise temperature Te = 30 K. Compute the noise factor.

Introduction / Context:
Receiver and antenna noise are often quantified via equivalent noise temperature (Te) and noise factor (F). Converting between them is common in RF link budget and system noise analyses.

Given Data / Assumptions:

• Reference temperature T0 ≈ 290 K (≈ 27 °C).
• Antenna equivalent noise temperature Te = 30 K.
• Definition: F = 1 + Te/T0 for an equivalent input noise temperature model.

Concept / Approach:

Noise factor F (linear) quantifies SNR degradation: F = (SNR_in)/(SNR_out). For a source at T0 with added equivalent Te, F = 1 + Te/T0.

Step-by-Step Solution:

Verification / Alternative check:

Convert to dB if desired: F_dB = 10*log10(1.1034) ≈ 0.43 dB; a small, plausible value for a low-noise antenna stage.

Why Other Options Are Wrong:

• 20, 100, 300: unrealistic linear F for such a small Te; imply massive noise.
• 0.9: noise factor cannot be < 1.

Common Pitfalls:

• Using 300 K instead of 290 K (difference is minor but standard uses 290 K).
• Confusing noise figure (dB) with noise factor (linear).

Final Answer:

1.1