diff --git a/docs/emane/antenna.md b/docs/emane/antenna.md
index 20c98304..2ffa44f2 100644
--- a/docs/emane/antenna.md
+++ b/docs/emane/antenna.md
@@ -333,6 +333,7 @@ Create `/tmp/emane/blockageaft.xml` with the following contents.
 ```
 
 ## Run Demo
+> **WARNING:** if using core-gui, you will need to open nd save the emane configuration
 1. Select `Open...` within the GUI
 1. Load `emane-demo-antenna.xml`
 1. Click ![Start Button](../static/gui/start.gif)