AG6K - Amplifier notes
G3SEK - Technical Notebook - The triode board - The tetrode board
PE1OGF - QRO page
SM5BSZ - Building High Power Amplifiers
YL2QM - QRO Page
YU1AW - HF & VHF Amplifiers
WA6BOB - Amplifiers Links
WB0NNI - Amplifiers basics
WB8ERJ - 813 Linear Amplifier Project

Tube database

http://www.qsl.net/ea4cbh/crv/CRV2.htm
http://hot-streamer.com/ross/projects/tube_coil/tube_details.htm

http://www.imagenisp.ca/jsm/136.html

ARRL (K9LA) - The Sun, the Earth, the Ionosphere
ARRL (W1AW) - Propagation Bulletins
Basics of radio wave propagation
DX Listeners' Club - Solar Terrestrial Activity Report
DXZONE.com - Propagation Resources
HFRADIO.org – Propagation (Reloaded every 15 min.)
MICHIGAN-TECH - Wechelcome to The Aurora Page
NASA – MAEL Radio Propagation Activities
NASA Space News - Sunspot Numerology
NASA - The very latest SOHO images
NOAA - Current Space Weather Indices
NOAA - Current alerts and warnings
NOAA - 3 day forecast
NOAA - 27 day forecast
NOAA - Weekly Highlights and Forecasts
NOAA - D-Region Absorption Prediction
NOAA - SEC List Server
NORTHERN VERMONT QRP SOCIETY (NVQS-N1QS) - Propagation
QST December 1983, pp.11-15 - HF Propagation: The Basics
QST, LabNotes, October1996, pp. 74-75 - Here Comes the Sun
QST August 2002, pp. 36-39 - The Brendan Trophies: Insights for the New Millennium
QST September, 2002, pp. 38-40 - Understanding Solar Indices
Radio Netherlands - The solar guide
SOLAR TERRESTRIAL DISPATCH - Near-Real-Time MUF Map (Updated every 30 min.)
TAPR (VE3JF) - VHF/UHF/Microwave Radio Propagation: A Primer for Digital Experimenters
WILLIAM HEPBURN - VHF / UHF Tropospheric Ducting Forecast
WM7D.net - K7RA's solar report (updated every friday morning)
WM7D.net - NOAA's 27 day forecast
WM7D.net - Cycle progression graphs from NOAA
WM7D.net - Historical solar charts
W6EL - W6Elprop ionospheric propagation software

Wireless Network Link Analysis
A path-loss calculator

Radio Line of Sight Plot Server
VHF/UHF: Allows you to make a request to a radio line of sight plot server. You receive a GIF picture of the elevation of each point on the earth between the starting point and ending point that you specify.

VOACAP Quick Guide
High-Frequency Ionospheric Communications Analysis and Prediction

HFWIN32
U.S. Department of Commerce NTIA/ITS Institute for Telecommunication Sciences High Frequency Propagation Models Notice: The Department of Commerce has made this HF propagation software available free of charge

HF Propagation Models from NTIA/ITS
ICEPAC, VOACAP, and REC533 Version 00.0908W (08 Sept 2000). Software is now FREE

Radio Mobile Freeware by VE2DBE
This software is a tool used to predict the performance of a radio system.

PropView
PropView uses the included IonCap propagation prediction engine to forecast the minimum and maximum useable frequencies between two locations over a specified 24 hour period.

WinCAP Wizard 3
The WinCAP Wizard 3 software package for high frequency radio communications system analysis and propagation prediction; also know as SkyWave analysis.

DX Atlas by VE3NEA (Afreet Software, Inc.)

MultiNEC Antenna Modeling Software
Combines antenna modeling and propagation predictions and lets you automate and animate both

Principal