This is a List of Beam Approach beacon system Units of the Royal Air Force.
By late 1941 the word 'Blind' was changed to 'Beam' as it was felt that blind did not give a reassuring feel to a system used when visibility was very low.
The change from Blind to Beam is evidenced in the two sets of Unit names in the tables below.
There were no physical beams in the system at all, rather it relied on a heavily distorted dipole radiation pattern using a single transmitter.
Instead of 'beams' it used a single heavily distorted toroid that was flipped left and right with a periodicity that simulated a morse code letter, the plane of equal field strength in this arrangement being mathematically equal to a line of zero width - a perfect 'beam' from an imperfect, cheaper, and simple radio transmitter.