The EF-10/20/40 may also be used on 20/30M by replacing the 40M tip with a 38” tip. This will raise 20M resonance a bit, but should not be a problem; especially if 20M was initially set to the CW portion of the band, or by connecting the stub to the choke end closest to the matchbox and reestablishing 20M resonance as desired. Alternatively, for 30M monoband use a 1/2 wavelength wire– begin with 46.5’ of wire.
Operation as a monobander on any band between 60M and 10M can be accomplished by removing the factory radiator and installing the appropriate 1/2 wavelength wire. Calculate the approximate length from L= 468/F(MHz). As an example a 25’ 10” wire will allow operation on 17M as a monobander. Initially, cut the wire a bit long and trim for best V.S.W.R.