The MUSA receiver had 16 channels, the output of which was combined through phase delay networks to provide an electrically steerable but very high directivity array. (Assuming a rhombic would have 15-18dB gain then the MUSA with 16 added another 12dB with a very sharp beam pattern)
In the UK, the Post Office, at Dollis Hill, produced a similar receiver to that designed by Bell Labs and a MUSA receiving station was set up on the marshes at Cooling in Kent to provide additional ‘high quality’ channels on the London to New York service.
This system was the ultimate in HF reception and provided a significant improvement in circuit availability and quality.
The receiver was perhaps the most complicated HF radio ever built employing around 1000 valves and therefore was very expensive. Hence it was only economic on heavily loaded trunk routes such as the London to New York service.
Given the time and use of valves, I think this whole antenna and receiving system was an astonishing piece of electronic engineering.