It's bordering on too simple, but since he only claims a range of 2m, I think it should work.
One thing to pay extra attention to, is the resonance circuit made up by L1 and SP1 (the US transmitter piezo).
This has to be at resonance at the frequency used (f_res=40kHz) and since different transducers will have different capacity (could be from say 5nF or less to 100nF or more), the value of the coil (mentioned as 330µH) will have to be adapted - or the frequency can be changed (within reason) to maximize the amplitude over the transducer.
To be in resonance (at 40kHz) with the 330µH inductor, the capacity of the transducer must be 48nF (0.048µF). Half the capacity needs twice the inductance and v.v. to keep f_res at 40 kHz
The more you change f_res from the natural mechanical resonance (and hence optimum sensitivity) of the piezo electric quarz crystal, which is the active element in a US sensor, the less sensitive it will be.
The more you move the f_res away from the frequency of the transmitters oscillator, the less amplitude (voltage) you will put on the transmitter crystal.
If you have a datasheet on the US pair, post a link to it and the frequency and value of inductor needed should be easy to find.