|Waterfall display of Russian over-the-horizon radar signal on 20 meters.|
(From IARU Region 1 Monitoring System website)
The ARRL Letter reports that the radar signals are 12 kHz wide, making 40 sweeps per second and using FM on pulse. An additional over-the-horizon radar was reported in northern Iran, operating between 6.078 and 7.022 MHz, with 81 sweeps per second and AM on pulse over a 44-kHz bandwidth.
(For those of you too young to remember it, the woodpecker reference in the title refers to early Russian OTH radar, back in the 1970s, which sounded like a woodpecker as it swept through the HF bands.)