I don't mean to say scale by dB, I mean scale by ratio of graph dimensions. Dennis is using what looks to be close to a 2 to 1 ratio of x vs y, whereas mine is not quite 1.5 to 1, so the Y scale is much more stretched out. This will magnify any ripples or ruggedness.
Also, it looks to me like Dennis has 45 dB represented on the Y axis, not 35 dB, so his dB scale should be pretty close to mine