Collections of Equipment History, Manuals, Guidelines
BatLabs
Motorola Specific Equipment References
Repeater-Builder
Repeater-Builder: A VAST Collection of Commercial Equipment References
Antenna References
Antenna Terminology
Basic Antenna Concepts
Antennas 101
Antenna and Counterpoise Basics
Antenna Types Illustrated
Folded Dipole Description
Duplexers
Tessco: Understanding Duplexers
Duplexer v Diplexer
Duplexer Reference
Duplexer Tuning Video
Generic Tutorials and Guides
Introduction to UHF & VHF FM Repeaters
Intermod, Co-Channel, Capture, De-Sense...
Wikipedia: Intermod
Wikipedia: Adjacent Channel Interference
Bandwidth
Operating Modes, Linking and Interconnections
Wikipedia: Amateur Radio Modes
AllStarLink
Wikipedia: D-Star
Wikipedia: DMR
Wikipedia: Digital Mobile Radio
Wikipedia: EchoLink
Wikipedia: Frequency Modulation
IRLP
Wikipedia: NXDN
Wikipedia: P25
NARCC Technical Committee presentation - 2014
Bandwidth, Channel Spacing, Deviation, Frequency Stability/Tolerance, Guard-band...
Radio Site and Station Essentials
SBASite - Commerical Safety Reference
BLM Climbing Safety Document
W. Reeve Article on NEC Implementation for Amateur Radio
SeaPac Presentation on NEC and Amateur Radio
Commercial Grounding and Bonding Paper
Motorola R56 at Repeater-Builder