[TowerTalk] vertical performance

[David]

I want to  run 20 feet of RG213 from the tuner to the top of a 10 foot section of tower and then to an unun with the output of the unun to a 15 foot vertical mounted to the top of the tower.   Should I use a 1 to 1 or a 4 to 1 unun?  One terminal of the output of the unun will be to the vertical and the other to 4 15 foot radials. Should I ground the radials to the tower of float them from the unun terminal? Antenna is to be used for 10 thru 20 meters. Any idea on how it might perform?  A 15 foot piece of wire might be added to the top of the vertical for use on 30 and 40 meters.  No change in radial length.  73's and Merry Christmas  David N5WMQ