Trumpets and Jesus' Return

The Old Testament mentions a festival for the blowing of trumpets. The Book of Revelation mentions the blowing of seven trumpets. Could there be some type of connection? What does the blowing of trumpets represent? What about the watchman role? When will Jesus return? Will Jesus return on the Feast of Trumpets? Do pretribulation rapturists have their order out-of-biblical sequence? What does the name Rosh Hashana mean? Should Christians keep the Feast of Trumpets? When is the first month? When is the seventh month? What happens at the opening of the fifth, sixth, and seventh seals? What about the seven last plagues. Dr. Thiel addresses these issues and also makes some speculations that he expects to fine tune in the future.