On radio, where that physical charm was, well, hidden, the results, we are told were starkly different.
Turns out that those results are questionable.
Here, let Mark Blumenthal explain it:
That result, however, has a few problems, the most important of which is the relatively small size and unrepresentative nature of the radio audience. It amounted to must 282 responses from Sindlinger's sample of 2138 respondents, but the pollster apparently misplaced the original data, because no information survived regarding the partisanship or vote preference of the radio or television subgroups. That omission is critical because, as Steven Chafee, a professor of communications at the University of California Santa Barbara has observed (2000, p. 334):
By 1960, those who could listen to debates only on radio were far from a random lot. Situated for the most part in remote rural areas, they were overwhelmingly Protestants and skeptical of Kennedy as a Roman Catholic candidate.That sounds plausible.