Engineers! Good grief Charley Brown.
OK, I'll be a little more objective and precise.
We had a TST we used on a 32" fifth wheel towed by a crew cab long bed F250. It lost signal often enough that I was shopping for a booster when we decided to get a new RV. It reported false alarms several times and often reported wrong tire pressures. Walking the receiver away from the rig it would lose signal completely at less than 50 feet of nothing but air. It was also more difficult to program and occasionaly forgot it's programming.
The new RV came with a SmarTire system. This one had two external antennas and a booster. It only covered the 6 coach tires. It was a complete waste of time. Senders would drop out more or less randomly and it reported false alarms often enough that we could not trust it. SmarTire is no longer selling systems for RVs, a good thing IMHO.
The EEZRV system was easy to program and did not require that the senders be mounted on the tire for programming: Press a couple of buttons, hold the sender to the receiver until the sender id shows up in the display, assign that sender to a tire position and slap a label on it. It's been perfect since the day I installed it. One thing I really like is how easy it is to link & un-link the towed vehicle.
I believe our coach has the usual construction: big cast iron rumbly thing in back, frame & walls etc between the towed and the receiver. It is not made out of air. The EEZRV has never had a dropout. If I remember correctly when I saw I was getting signal from the towed across the parking lot the signals were coming all the way through the rear of the coach to the receiver in the front. That impressed me because our previous systems were so poor. We travel with the usual array of electronic and wireless devices. Probably more than most. Wifi, cellular, Bluetooth, NFC and so on.
Reading the reviews about EEZRV on Amazon I saw that very few people had to buy boosters and several who assumed they'd need one didn't. My advice is to try it without one first.