Total posts : 45366
I think outside mounting everything is doable. Water proofing the TH indoor unit could prove problematic. Might want to confirm operating temperature ranges on the unit and determine if air cooling (fan) will be necessary and adequate.
The coax should be fine. The radio engineers and novice engineers should comment on the coax. I’ve always thought coax to provide loss, but unsure how it may or may not enhance AM transmit.
Power and audio can be accomplished over an outdoor ethernet cable. I use gel filled burial grade ethernet cable. Should be able to pump power over the ethernet on the spare pairs (assuming you aren’t using gigabit). Alternatively, can buy an official POE injector.
Assuming the 5.8 receiver is to get signal/data to the antenna stack? Doable there.
Need to determine the watt consumption on these pieces prior to considering solar. My guess is you need upwards of a 100 watt panel if this is 24/7 operation.
Feel free to ask whatever. Glad to help with these off grid and tech style installs.