A 5db noise figure would be very good for an HF radio front end, 10db is certainly not bad. The total noise figure for the receiver is probably not published but as long as there is sufficient gain to overcome the atmospheric and thermal noise on HF it shouldn't matter. I never worried too much about front end noise figure until I got above 50 MHZ.
Originally Posted by SM0AOM
i'm sorry you don't have the experience or understanding to realize that others possess a skill set that you seem to dismiss as fantastical.