well according to your zip code on to OTA channels web site
http/www.antennaweb.org/Stations?Address=89149&AntennaHeight=False&Latitude=36.2684007&Longitude=-115.2956118
says you have Up to 74 channels from 26 over-the-air stations may be received at this location.
the key words is 26 stations...
for example channel 2, will have 2.1, 2.2, 2.3 2.3 (on that web page click on a channel to get sub channel listings)
you should get approx 74 channels yes, on 26 stations. now for example in my area 77009 I should be getting Up to 132 channels from 29 over-the-air stations may be received at this location. , but reality I have 25 working channels and far from the 132 channels that actually are "channels" because many are only online a few hours a day (community etc.) a few have really crappy transmission signals from sub-channels.
what can be done... not sure to be honest, in my case it could be possibly fixed with reorientation but in your case I dont think it possible applies.