Index: trunk/BNC/src/bnchelp.html
===================================================================
--- trunk/BNC/src/bnchelp.html	(revision 7795)
+++ trunk/BNC/src/bnchelp.html	(revision 7796)
@@ -3438,18 +3438,12 @@
 </p>
 
-<p><h4>2.13.1.11.3 <a name="pppsnxAc">Analysis Center - Optional if 'SINEX TRO Directory' is set</h4></p>
+<p><h4>2.13.1.11.3 <a name="pppsnxAc">Analysis Center - Mandatory if 'SINEX TRO Directory' is set</h4></p>
 <p>
 Specify a 3-character abbreviation describing you as the generating Analysis Center (AC) in your SINEX troposphere files. String 'BKG' is an example.
 </p>
-<p>
-Default is an empty option field, meaning that you don't want to specify an Analysis Center in your SINEX troposphere files.
-</p>
-
-<p><h4>2.13.1.11.4 <a name="pppsnxSol">Solution ID - Optional if 'SINEX TRO Directory' is set</h4></p>
+
+<p><h4>2.13.1.11.4 <a name="pppsnxSol">Solution ID - Mandatory if 'SINEX TRO Directory' is set</h4></p>
 <p>
 Specify a 4-character solution ID to allow a distingtion between different solutions per AC. String '0001' is an example.
-</p>
-<p>
-Default is an empty option field, meaning that you don't want to specify a solution ID in your SINEX troposphere files.
 </p>