If your area is anything like mine, your "40 channels" are substantially less than that. Most of the channels that you can theoretically receive are duplicates that are being broadcast from different towers. Being able to pick up ABC from three different towers doesn't really count as three channels. In my neck of the woods, you can get the main networks (ABC, CBS, NBC, PBS, Fox) and one or two subchannels for each network. There are also a handful of shitty other channels like foreign language channels.
Take a closer look at the reception map for your area and decide if you can pick up all the channels from one general direction. In my area, there are two towers that are about 15 degrees apart and two other towers that are in different directions. I use a roof mounted directional antenna aimed between the two towers and get all the channels in my local area. It is this antenna: https://www.channelmaster.com/Digital_HDTV_Outdoor_TV_Antenna_p/cm-2018.htm . Also note that most areas only broadcast on UHF or Hi VHF channels so a "digital" antenna can be smaller, lighter, and less expensive by omitting the parts of the antenna used for VHF. Although my antenna is directional, I can also pick up channels in other directions because I am very close to those transmitters.