Why 2BKX and what does it mean?

It was my Grandfathers callsign that was issued to him by the general post office in the 1920's when he was conducting wireless transmitter experiments.

He was issued an "artificial aerial" licence which were issued between 1920 - 1939 starting with the number 2 followed by three letters. This licence allowed him to build a "non-radiating" wireless sending apparatus meaning that the signals will not radiate outside of the building in which it was installed. It was intended that the effects produced by the transmitter could be detected or measured either by direct connection or within a few feet using a receiver with an "open" aerial.

Experimental Wireless Station in 1927

Experimetnal Wireless Station 1927