That means that the stock antenna in the FP Apollo is located in the worst possible orientation and inside a Faraday cage.
That's correct!
Cheers, the penny finally dropped! I'll explain in case other beginners benefit from a 'For Dummies' explanation:
~snip~
That's all correct, too, thanks for writing such a detailed guide / explanation.

Will bookmark it for future reference.
Could you please let me know which fan would be ideal for the Apollo ASICs ? I'm happy to buy some and replace them if they are now available.
I'm not an expert on fans, but I'd go Noctua (Industrial) or Delta (though those aren't known for being quiet, but certainly high-performance.. so may perform well at low-RPM, too).
I would like a high quality fan that can reach high speed and air flow when required, but turns off completely (or at least so slow that it is very silent) when the miner temperature is below the -fan_temp_low setting.
Does the stock fan continue running at 1800RPM even when it's set to 1% for any temperature (-fan_pwm_low 1 -fan_pwm_hi 1)?