Thanks for the info! You'd think people would try to avoid interference a bit better than that considering CHU is always on that frequency.OK, you have two different signals here. Yes, they may have been hitting the same frequency, 7850 kHz, on different days, but they are two different signals and probably unrelated.
They are both radar, but different kinds of radar.
The first is a typical Chinese BPSK coded radar at a fairly common rep rate for them, about 32.4 Hz. On lower frequencies they often use double that rate. These radars can (probably, the Chinese ain't really being specific) track ships and aircraft.
These kinds of radars move around in frequency, as needed, to leverage current propagation conditions. They are typically on many frequencies per day, and they may not be on the same frequency, or frequency set, every day.
The second appears to be CODAR or WERA radar, and there might be more than one radar in overlapping operation, both the sounds and your screen shots seem to indicate more than one source. This is an FMCW or IFMCW radar that chirps across a specific bandwidth at a specific moderate rate, they often are about 1 sweep per second, but they can be faster, or slower, than that. When you have more than one interleaved this can make it sound much faster. These radars are specialized coastal radars that typically monitor ocean wave and current activities.
On the bright side, I guess we can consider this mystery solved!