Identify two common indicators of jamming versus poor signal conditions (multipath or fading).

• A. Jamming: elevated EIRP in a specific direction, constant or bursty interference; Multipath: increased delay spread, correlation dips
• B. Jamming: lower noise figure; Multipath: stable spectral lines
• C. Jamming: decreased C/N0; Multipath: decreased SNR
• D. Jamming: increased Doppler shift; Multipath: none

Answer: (A)

The core idea is to distinguish intentional interference from natural signal distortions by looking at how the interference presents itself in power and timing versus how the channel behaves.

Two clear indicators: if you observe an unusually high radiated power coming from a specific direction, paired with interference that is either steady or comes in bursts, that points to a directed jammer. The elevated EIRP in a particular bearing shows energy is being transmitted with the aim of overpowering your link, and the pattern of interference being constant or bursty fits how a deliberate jammer behaves.

In contrast, problems caused by multipath or fading reveal themselves through the signal’s time-domain spreading and the way the signal components interfere with each other. Increased delay spread means the signal occupies more time due to multiple paths, and correlation dips reflect destructive interference among these paths at certain delays. These are propagation effects, not a directed energy source.

Why the other options don’t fit: lowering the receiver’s noise figure isn’t typical of jamming and wouldn’t explain a directional, intentional source; stable spectral lines aren’t what multipath/fading produces—multipath tends to cause time dispersion and fluctuating spectral characteristics rather than fixed lines. Doppler shifts can appear in various scenarios, and multipath isn’t described as having no effect, so that choice isn’t reliable for distinguishing the two cases.