The Polish Wikipedia (yeah I know) says:
In the 1970s it was proved that the system (S-75) is effective in engaging seaborne surface targets when fired from launchers placed on a cliff or high shore with the launcher beam set at the minimum elevation angle.
Typical Wiki, partly true...
The PU is always elevated higher than the SNR.
(To give the missile enough elevation above the SNR LOS to fall during the first 3sec unguided flight.)
When the SNR is at 0 elevation, it locks down. (black instrument hand)
The PU this time is elevated at 18degree. (red instrument hand)
So the real question, is if the SNR is able to lock on the ship, that is below the SNR LOS?
This is where H<5 comes into the picture, as it actually moves the LOS down 3 degree.
So now the SNR will only lock down at -3 degree. (at 10km range, it is more than 500m below the SNR)
