Interesting; I pronounce "loch" as "lock" and Merriam-Webster seems to agree. https://www.merriam-webster.com/dictionary/loch I guess you're referring to the UK pronounciation listed
here instead?
http://dictionary.cambridge.org/us/pronunciation/english/loc...
I thought the use of the specific word "loch" would have been clear enough, but apparently the pronunciation of that word I thought I'd heard a lot on the BBC is not known as widely as I thought. Maybe I'm misremembering. None of the pronunciations you linked to is what I intended. See https://en.wikipedia.org/wiki/Voiceless_velar_fricative or https://en.wikipedia.org/wiki/Voiceless_uvular_fricative , as well as https://en.wikipedia.org/wiki/Scottish_English#Phonology .
If I were consciously trying to pronounce "char" as an English speaker would, I would probably say /tʃɑr/.