One good place is
airnav.com which as an example you could select
Corvallis Municipal Airport and then go down the page to:
Nearby radio navigation aids
VOR radual/distance VOR name Freq Var
CVO at field CORVALLIS VOR/DME 115.40 18E
EUG r333/22.8 EUGENE VORTAC 112.90 20E
ONP r079/33.3 NEWPORT VORTAC 117.10 19E
I take the information there and then try to use that info on GoogleEarth to locate the tacan or VOR precisely. There are other web resources (FAA?) that also have precise location data once you have the name of the NAVAID. Use multiple sources, they should match. If you can visually see the NAVAID, even better.