Day-to-Day Variability of the Ionosphere
Is the Ionosphere In Step
NM7M The Little Pistol's Guide to HF Propagation This is a 15 Megabyte file. A special thanks to NM7Mís daughters and son for giving me permission to put this (and Bobís other books) on my web site.
NM7M Long Path Propagation This is a 3 Megabyte file.
NM7M Long Path Propagation - Revisited This is a 19 Megabyte file.
Where Do the K and A Indices Come From
The Formation of the Ionosphere
Disturbances to Propagation
A Look Inside the Auroral Zone
Propagation Plannning for DXpeditions
Measuring the Ionosphere
NM7M Contributions to Propagation
Did We Lose a Solar Cycle
Old Sunspot Data