In my experience with Baofeng and BTech (made by Baofeng, and cloned a lot) radios, their receive sensitivity on the fringes of a repeater acts really funny, like they are in sleep mode (even though sleep is disabled). Even with the squelch completely open, a distant repeater will often not be received properly, but will eventually come in strong, until the carrier drops, and then it’s insensitive again. So you miss the first few seconds of every transmission. OK with strong nearby signals, so it’s probably some intrinsic property of the radios (PLL lock range, sensitivity, selectivity, adjacent channel rejection, sleep mode active even when turned off (see firmware bugs), or something else). Doesn’t really matter, but it does make them unsuitable for some uses.
Small world! I just set up a transciever with WSPR and with 5 watts from Massachusetts I’m getting a similar map, with my transmissions heard in Hawaii, Mebourne, Antarctica, etc. Just getting into the HF thing, and digital modes, but it looks like this is going to definitely be a means of communications to get familiar with!