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/