Ask HN: I suck at technical telephone interviews. Is it for life?

I kind of happened into being a team lead, with no formal background in coding. And whilst I can code OK, and probably do an OK job in onsite interviewing, I cant shake the suspicion that my telephone interviews are unfair to candidates.

I've tried various things, going very wide and asking only general hand wavy questions (what's interesting about Java 8.. have you heard to Go etc) or asking about specific data structures like Hashmaps and so on. None seem very satisfactory, and I usually end up quietly listening to long harangues with low informational content (for my purposes).

I suspect there are tried and tested interview questions that `work` handed down from programmer to programmer, just, I lack access to a mentor knows these dark arts. So what makes for a great first round telephone interview for a coder then? Questions you always personally ask?