Too high in Frequency for NVIS, perhaps a dipole with a 1:1 Balun cut for the frequency. Have the feedpoint up 36' because it will be an inverted "V" This is now an omni directional antenna. So the bottom of this antenna should be approx. 27' above the ground. This type of antenna works well for areas that don't have too much ground conductivity. The balun is vital to feeding the dipole. Balun will keep common mode away, it will allow for the max of RF energy to the antenna. A 1:1 Current Balun @500watts or more. Cut the wire to the wave length for Channel 20. Use insulators get as high as possible 36' is great.....less than 20' ft in 12AWG you can make a balun out of coax (Google it)(ugly balun) This is also known as a choke or pay for a Balun $49.00 Nothing is guarenteed, but this is your best option.The only thing I can think of to add would be to setup a dipole and try NVIS with it, but I would not hold my breath.