To the OP - You are aware of the FCC rules regarding antennas, are you not?
http://www.fcc.gov/guides/over-air-r...n-devices-rule
There are only very limited restrictions that your HOA can impose. "The rule prohibits most restrictions that: (1) unreasonably delay or prevent installation, maintenance or use; (2) unreasonably increase the cost of installation, maintenance or use; or (3) preclude reception of an acceptable quality signal."
I would certainly consider the earlier posts here about the Lava antennas before purchasing one.
https://www.google.com/search?q=site...m+lava+antenna
More height should help reception. At the least, it will get you above any surrounding vegetation, which can have a significant negative impact on reception. 18' is pretty low. You have two main groups of signals you might want to receive. Use of an "omnidirectional" antenna that does not focus on one or the other of these headings will reduce your chance for reliable reception. I would first try for the large group of stations originating from Orlando, at ca 330 degrees magnetic. You also have a bunch of stations from the West Palm Beach area, it appears.
Whether the above poster's 10"x12" antenna would meet your needs I do not know. Personally I would go with a larger conventional antenna like the Antennas Direct DB4e, or DB8e if you can accept the larger size. The Eagle-Aspen is another popular and inexpensive UHF-only antenna, though not as sensitive as the DB4e or DB8e.
As mentioned, WESH NBC is a VHF-high station which probably would not be picked up by these nominally UHF-only antennae. Note that in general longer the wavelength is (ie lower the frequency), the larger the antenna has to be. VHF is lower than UHF. You should be able to easily get WESH by adding an antenna like the Antennacraft Y5713, but this has a 5' beam and looks like the stereotypical TV antenna. You could also use a UHF-VHF combination antenna, like the Antennacraft HBU33. Again, a large antenna that will have a very low HOA acceptance factor. Or you could combine an Antennas Direct Clearstream 5 with one of these UHF antennas to get WESH too. The C5 is fairly compact and may have a more acceptable appearance to you. Pricey though, at $180 vs $30 for the functionally similar Y5713.