Visual Topographic Maps: https://en-gb.topographic-map.com/maps/lrp2/Michigan/
Amateur Radio License Map: https://haminfo.tetranz.com/map/AD8GN
airLink Line of Sight Visualizer tool: https://link.ui.com/#
APRS Menolink Current Propogation Mapping tool: http://aprs.mennolink.org/
Tropospheric Ducting Forecast: https://www.dxinfocentre.com/tropo.html
APRS Direct: https://www.aprsdirect.com/