19-09-2018, 04:01 PM
You are conflating two different requirements.
Once origination of material for BBC-1 was switched to 625 lines in 1969, there was a requirement for continuous conversion to 405 lines whenever BBC-1 was in service. This took place at the high-power transmitting sites, where there were main and standby CO6/501 converters installed with provision for remote changeover from the control desk. By contrast, the requirement to convert the other way was an occasional one where, usually, plenty of notice could be given via the facilities booking system. (It is worth pointing out that there had been a similar requirement for non-continuous 625 to 405 conversion for some years, since the majority of material arriving via the Eurovision PNV was 625 lines).
The CO6/509 was designed in the early 1970s (the EDI is dated July, 1974: appearance of an EDI usually indicated that the relevant equipment was, in principle, available for internal order) when there was no date in prospect for the end of the 405-line service. There were a number of stimuli for the new design: supply difficulties with some of the semiconductors used in the analogue design was one, as was a desire to reduce the power overhead of the equipment. A further consideration was that this was the era of de-staffing many of the transmitter sites, and so there was a need for a converter which was regarded as sufficiently reliable not to require permanent on-site engineering support.
The design effort could be justified by the number of units required in the field, and the need for continuous operation of the service at the customary levels of reliability. Neither of these applied in the case of the CO6/502. The issue of parts availability remained, but this was considered tolerable in the context of a single example in occasional use only. Even by the BBC's sometimes profligate standards, it would have been impossible to justify the design and development of a digital equivalent of the /502 until the ACE offered the facility, effectively at no cost.
There was certainly no deficit of skill amongst the staff at the transmitting stations, and it is disrespectful to suggest otherwise.
A small point of detail, but the CO6/502 was installed in Standards Converters at Television Centre, behind the South Hall lifts.
Once origination of material for BBC-1 was switched to 625 lines in 1969, there was a requirement for continuous conversion to 405 lines whenever BBC-1 was in service. This took place at the high-power transmitting sites, where there were main and standby CO6/501 converters installed with provision for remote changeover from the control desk. By contrast, the requirement to convert the other way was an occasional one where, usually, plenty of notice could be given via the facilities booking system. (It is worth pointing out that there had been a similar requirement for non-continuous 625 to 405 conversion for some years, since the majority of material arriving via the Eurovision PNV was 625 lines).
The CO6/509 was designed in the early 1970s (the EDI is dated July, 1974: appearance of an EDI usually indicated that the relevant equipment was, in principle, available for internal order) when there was no date in prospect for the end of the 405-line service. There were a number of stimuli for the new design: supply difficulties with some of the semiconductors used in the analogue design was one, as was a desire to reduce the power overhead of the equipment. A further consideration was that this was the era of de-staffing many of the transmitter sites, and so there was a need for a converter which was regarded as sufficiently reliable not to require permanent on-site engineering support.
The design effort could be justified by the number of units required in the field, and the need for continuous operation of the service at the customary levels of reliability. Neither of these applied in the case of the CO6/502. The issue of parts availability remained, but this was considered tolerable in the context of a single example in occasional use only. Even by the BBC's sometimes profligate standards, it would have been impossible to justify the design and development of a digital equivalent of the /502 until the ACE offered the facility, effectively at no cost.
There was certainly no deficit of skill amongst the staff at the transmitting stations, and it is disrespectful to suggest otherwise.
A small point of detail, but the CO6/502 was installed in Standards Converters at Television Centre, behind the South Hall lifts.
There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey.
John Ruskin
John Ruskin
