ANTENNA SYSTEMS / RECEIVERS / PROPAGATION
These notes explain why a radio path works—or fails—and what can be measured to improve it. The goal is practical, repeatable station engineering rather than vague claims about equipment gain or propagation.
Antenna Fundamentals
Wavelength, polarization and installation
Feed-Line Loss
Loss in dB, power budget and coax choices
Low-Noise RX Systems
LNA position, noise figure and gain
RF Relay Sequencing
PTT order, isolation and LNA protection
Power Dividers & Stacking
Amplitude, phase, spacing and verification
Terrestrial Path Planning
Radio horizon, terrain and atmospheric paths
VHF/UHF Propagation
Sporadic-E, meteors, tropo and EME
Common-Mode & RFI
Chokes, shielding and measurement
Rover Operations
Field layout, IF choices and antenna systems
K5QE Presentations
Marshall Williams: original papers and slide decks
Field Day
Portable station planning and operating
HF Contesting
CW, SSB and digital operating strategy
VHF & Above Contesting
50 MHz through microwave grids
How these articles are organized
Most projects begin with a requirement, a drawing or calculation, and a test plan. Preliminary dimensions, simulations and assumed conditions should never be presented as measured results. Where no field data exist, the text identifies the discussion as guidance or a project concept.
Featured reference material
The receiver and protection guides are key starting points: Low-Noise Reception Guide and Relay & Sequencing Guide. Marshall K5QE’s primary source and related presentations are gathered in his technical archive.