If you kill Dobson to finish your first test for the BoS, you gain infamy with the NCR even after breaking his radio down to pieces AND
knowing from him that nobody knows he's there. WTF?

The only alternative left if your speech skill is too low to persuade him is to keep killing the radscorpions nearby until you level up
but, quite frankly, why bother with something immune to any kind of explosives?

Also, is it intended that Dobson appears at 2 or more possible locations when you get this quest?