I've been through this entire indoor, HOA issue as well. What worked for me was a 1/2 wave dipole with 1:1 balun. I have it strung on my 2nd floor lanai (screened terrace). The terrace is big enough where I can string it totally horizontal. Mine is strung east/west so is directional kind of N/NE to S/SW. Great for the east coast and UK because I am on Florida's east coast. Lousy for out west like California and Arizona. It works great within these limitations.