Docs: Add note about hotspot settings

Author: nseidle

docs/gis_software_ios.md

@@ -87,8 +87,9 @@ From the map view, we can see our location with very high accuracy. We can now b
 
 ArcGIS Survey123 connects to the RTK device over TCP. In other words, the RTK device needs to be connected to the same WiFi network as the device running ArcGIS. Generally, this is an iPhone or iPad.
 
-![WiFi network setup via Web Config](<img/ArcGIS/SparkFun RTK - ArcGIS WiFi Hotspot Web Config.png>)
+**Note:** The iOS hotspot defaults to 5.5GHz. This must be changed to 2.4GHz. Please see [Hotspot Settings](gis_software_ios.md/#hotspot-settings).
 
+![WiFi network setup via Web Config](<img/ArcGIS/SparkFun RTK - ArcGIS WiFi Hotspot Web Config.png>)
 
 ![Adding WiFi network to settings](<img/ArcGIS/SparkFun RTK - ArcGIS WiFi Hotspot.png>)