I have a similar issue with height. I am able to squeeze in an 75, 40, 20, 10 fan dipole but the center height is only about 19' and I had to drop the ends~4' each and ended up at about 6' on 75, definitely NVIS, suits me for the nets I want to participate in. 40 gets OK DX at times. 20 is great. 10 is so, so. I think because of the way I wound my choke - primarily for 75/40. I used an end fed with a balun and got great results with 63' of wire. I had to use a tuner but my signal reports were good. Top end was about 19' and lower end about 8'. Build a wire antenna and give it a try. If you have the capability you might consider a horizontal loop. They are very quiet usually. Good luck, 73, de n1plv