History
Southampton was later served from Thornhill but a 2 GHz link was installed at the central exchange as part of the arrangements for Southern Television. Broadcasts commenced in August 1958 from a transmitter at Chillerton Down on the Isle of Wight. The company's studios were established at Northam, around one mile from the exchange. The necessary "vision circuits" for ITV contractors were arranged by the Independent Television Authority (ITA). As a minimum this would be an incoming "network" feed and an outgoing connection to the transmitter. The contractor would substitute local programming and advertisements. The "network" content would be switched by the Post Office according to schedules agreed with the ITV contractors.
For Southern the PO added an additional channel to the London to Rowridge link originally set up for BBC television. The two transmitter sites on the Isle of Wight were connected by cable and the ITV circuit was sent via 2 GHz link between Chillerton Down and Southampton, continuing via cable to the studios. The studio output was sent back to the transmitter over the same route. The Southern franchise extended to Kent and the ITA provided a second transmitter near Dover - requiring a second vision circuit. This was achieved by adding a return path from Chillerton Down via Rowridge to London where it was connected to an existing trunk cable to Dover. The option to transmit different content from Dover was provided by having two outgoing circuits from the studio (the resulting "spare" incoming circuit allowed outside broadcast links to user Chillerton Down as an "injection point").
An advertisement from GEC in the Post Office Electrical Engineers' Journal, January 1962, shows the Southampton to Chillerton Down 2 GHz link with three channels in each direction. From analysis of the associated diagrams their use was: Chillerton Down - Southampton: network feed from London; outside broadcast from Chillerton Down; shared "protection" standby channel. Southampton - Chillerton Down: Chillerton Down transmitter feed; Dover transmitter feed (via London); "protection".
A new Television Network Switching Centre was built in Western Esplanade, across the road from the exchange, in the late 1960s in connection with a new route from London to Southampton. The link to Chillerton Down was withdrawn once the new arrangements were in operation.
Notes:
It would be possible, in theory, to use the "Dover" circuit to send programmes
to the wider ITV network, via London. A circuit specifically for this purpose
was added later.
There is no evidence the initial facilities at Southampton were shared with the
BBC. A regional BBC studio had opened in 1958 but no information about a link
to Rowridge (and onwards to London) has been found.
