March 11, 1998

Patching the Software for the 1st Printing of the 18th Edition of 
"The ARRL Antenna Book" 

   The YT and TLA programs have been significantly upgraded in 
the 2nd printing of "The ARRL Antenna Book." This document 
explains how to patch the original files from the 1st printing to 
upgrade them up to the level of the software included with the 
2nd printing. There is no charge for this upgrade for legitimate 
purchasers of the 1st printing.

   Assuming that the default subdirectories were used for the 
original installation, the following files are upgraded:

\ANTBOOK\TERRAIN\YT.EXE
\ANTBOOK\TERRAIN\YT.TXT

\ANTBOOK\XMSNLINE\TLA.EXE
\ANTBOOK\XMSNLINE\TLA.TXT

   The patching procedure is to copy the PATCHYT.EXE file into 
the \ANTBOOK\TERRAIN subdirectory (or whichever subdirectory you 
first installed the terrain files). Then type PATCHYT [Enter]. 
The program will search for and verify that valid copies of the 
YT.EXE and YT.TXT files are in that subdirectory, and then will 
patch them to bring them to the latest level. 

   The procedure for the TLA upgrades is similar. Copy the 
PATCHTLA.EXE file into the \ANTBOOK\XMSNLINE subdirectory and 
type PATCHTLA [Enter]. 

   NOTE: If either patch fails, reinstall the software from the 
original diskette supplied with the 18th Edition of "The ARRL 
Antenna Book," and rerun the patching program. Please read the 
new documentation files YT.TXT and TLA.TXT for each program to 
learn about the new features.

   If there are any questions or problems, contact by e-mail Dean 
Straw, N6BV, at n6bv@arrl.org.