To find out, I did the following test:
- run the ATS 909 with the Octaplumb
- run the AR3030 with the Octaplumb
At the same frequency, measuring SNR (using WSPR) of stations receivable via ground wave.
On 600m, that was the result:
It seems, the AR3030 has got a 11dB advantage in SNR over the ATS 909. In other words, the relatively inexpensive ATS 909 is just 11dB short (in SNR) to one of the world's finest receivers.