What I'm not sure about is the compatibility or lack of between 8VSB and OFDM (Orthogonal Frequency-Division Multiplexing) as far as using a ATSC1 (8VSB) device to 'read' ATSC3 (OFDM) signals other than just signal strength and looking at the RF haystack which I assume wouldn't be a problem.
Their specs list this for ATSC & ATSC3 (see the attachment in Open Office document format); Note these three in ATSC3 that are different than ATSC; Echoes, BCHBER & LDPCBER
It's not the differences between the two modulation schemes (which is a subject in itself), but how that affects related test equipment.