diff --git a/handbook.tex b/handbook.tex
index 57a98a7..d42ba2f 100644
--- a/handbook.tex
+++ b/handbook.tex
@@ -194,9 +194,9 @@ for larger transistors.
 \chapter{Telecommunications}
 \section{Amateur radio}
 \paragraph{HF frequency allocations (region I)}
-
 \paragraph{Q-code}
 \paragraph{Purity limits}
+\paragraph{Ambient radio noise}
 
 \section{Character encodings}
 \paragraph{7-bit ASCII}