Case Study 7: Noise Heaps

Symptom:

Spectrum display shows spikey heaps of noise at various frequencies.
The noise is broadband.

Analysis:

Suggests:
Possible sources:

Mitigation Steps:

Test Isolation: Insert a common-mode choke (ferrite on coax, Mix 31 for HF) near the antenna and near the receiver.
Check Grounding: Ensure the feedline shield is grounded at a single point.
Re-route the Cable: Keep coax away from noise sources (AC lines, routers, computers).
Improve Shielding: Use higher-quality coax like LMR-400 or clamp ferrites on both ends.

A battery charger in reconditioning mode:

The same charger in charging mode: