This is Inverted V antenna that can be used for both CW and SBB. SBB part is resonant at 3735 kHz, for CW at 3535 kHz.
12V relays are used to switch between SSB and CW, two coils are used to lower the frequency.
Construction details are available for Registered Users
Operation: When there is no voltage across relays, antenna works in SBB mode. When 12V is applied across relays, inductive elements start to work and antenna works in CW mode. This means that you need 12V power source with a switch as well. Relays are best fed through separate twin-lead cable.
BalUn: if the compact solution is needed, instead of the Air core RF choke, we can use torus ferrite core. Details about construction are in “BalUn” section of the book.