ABC TV at GH in the Fifties

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TELEVISION BROADCASTING
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Technology
The technology available was based on the use of Vacuum Tubes (Valves) with their high voltage power requirements. As valves lost their emission with time the equipment stability was reliant on testing and replacing faulty valves virtually on a continuing basis. Daily alignments of equipment were required to maintain specifications.

The following are some of the major items of broadcast equipment installed in the Gore Hill television studios from 1956 to 1959:

Master Control (Click for a picture)

Marconi Control Desk containing an 8 input x 6 output vision switcher. Two outputs were for transmission the others for preview and monitoring. Sound and vision were married ie a sound switcher followed the vision switcher. Marconi BD 819 TV Monitors (BD stood for "bloody disaster"!) were used as precision monitors and Marconi Waveform monitors were initially employed. Essentially the gear was extremely unstable and was soon updated as funds became available.

Dual Marconi Sync Pulse Generators (SPGs) were used with a remote SPG Changeover switch. A Sync Gen Locking unit enabled an SPG to be locked to a remote source so that seamless vision switching could be made in integrating studio and remote pictures.

Marconi Line Clamp Amplifiers were used on each of the vision switcher outputs. Their purpose was to maintain a constant black level irrespective of vision content. Most amplifying equipment in those days was AC coupled meaning that pictures with a high contrast level and pictures with a low contrast level would display different black level on the TV screen. The line clamp amplifiers restored the black level to a constant reference point so that with scene changes black remained black. They could also be used to insert a clean synchronising signal.

Station timing was controlled via a Master Clock system. A pendulum time piece was accurately set each day against the PMG's talking clock. Pulses from this clock were relayed throughout the station controlling wall clocks. A correction was made at 19 minutes past the hour if the remote clock was not in range. In the case of the individual clock it would fast forward to 20 minutes past the hour then stop but restart again on the 20 minute time pulse sent from the master clock. In this way the synchronisation of clocks was maintained. Yes, it did happen; clocks were put to air during correction time where the clock would rapidly advance and stop at 20 past the hour until time caught up.

A diesel powered Generator provided back up power in case of mains power failure and was operated remotely from Master Control for test runs. It had an automatic changeover with a delay of about 10 seconds when the power failed. Manual restore could be scheduled when the mains power resumed allowing an appropriate announcement to be made warning viewers of an interruption.

Telecine (Click for a Picture)

Two Emi Flying Spot Scanners using continuous motion film coupled with automatic shrink generators to eliminate interlace jitter. A 16mm and a 35mm projector with a swivel mirror changeover was used. A 35mm Slide Projector was also included. Their design was unique in that the electronics employed did not use any electrolytic capacitors only paper dielectric types. In addition the high voltage transformers used were of the oil filled variety resulting in components that were huge in size. Individual metering of each valve current was possible via rotary switches however the poor reliability of the switch contacts, ultimately rendered the system unusable.

Different sound on film systems were catered for. Optical sound required good focus of the sound lamp at all times and a switch over could be made to a magnetic head for side striped film ie one with a magnetic edge track. In addition a 16 mm Magnetic replay unit could be locked to the telecine machine to enable full quality sound. Accurate loading of picture and sound films was essential before locking so that vision and sound would be in sync.

You guessed it, no sound from the violinist on opening night was because the optical/magnetic sound switch was in the wrong position!

In the late Fifties two Pye Telecine machines were installed.

Telerecording (Click for a picture)

A Fernseh 16mm Flying Spot Machine with a separate 16mm sound recorder was used. Two film cartridges could be loaded each recording a section of the programme. An overlap in recording was possible by starting the alternate cartridge before the previous one ran out. After recording the programme the cartridges went to film processing for developing. The segmented sections were edited after processing to make a continuous programme. Precise film frame matching was essential to maintain accurate sound sync throughout the programme.

It was possible to lay a magnetic side stripe on the film after which the sound could be redubbed in sync to make a composite film. This potentially provided better quality sound than the direct optical recording but fell short of the quality of separate sound and film. The difficulty of side striping in those days was maintaining a uniform stripe thickness when laying the magnetic film.

Film Processing (Click for a Picture)

Adjacent to the telerecording area was the film processing dark rooms. During processing the dark rooms were lit only by red lighting. A continuous motion developing machine was used requiring the film cartridge to be placed on the equipment and its leader stapled to the tail of the previous moving film. A series of pullies and rollers enabled the tail to be held for stapling, but not for long. Constant processing speed and correct developer and fixer temperatures were essential to provide correct contrast and gamma rendition. At the output after developing, the film was dried in heat chambers as it continuously moved through the equipment and stored on film reels. Yes, precisely timed reel changes were required where the stapled section had to be cut out and the leader of the next developed section slotted in to a new reel. Ultimately the developed sections were then edited into a continuous programme reel.

The silver halide, a by-product of film developing was collected in tanks and shipped out for recycling.

Outside Broadcasts (Click for a Picture)

Pye OB Van using 3 inch Image Orthicon Cameras fitted with a 4 lens rotating turret to enable lens changes from wide shots to close ups. There were 3 cameras with the van as well as vision and sound mixing facilities. A mobile power generator trailer could be used in remote locations if AC Mains were not available. As there were no remote recording facilities at the time all output from the van was live and had to be relayed back to Master Control for direct to air transmission or through to telerecord for recording.

Links (Click for a Picture)

Essentially there were three communication requirements to be linked from an OB. The vision signal, the sound signal and talkback between station and the van.

Raytheon VHF Links were used to relay the vision back to Master Control. Sound on link was also possible but it was transmitted within the same vision bandwidth which resulted in a degradation of picture quality. It was therefore normal for the sound to be relayed by a programme line often temporarily provided by the PMG department for the occasion. Programme lines were spare telephone lines connected from the site location back to master control. The telephone lines were equalised ie frequency boosted to extend the bandwidth to improve audio quality. 7 Kc, 10 Kc or 15Kc lines could be requested depending on distance and costs. The higher bandwidth lines being most expensive. An unequalised telephone line could also be ordered. It was known as a tie line and was used for talkback and communication purposes. In areas where no tie lines were available two way UHF transceivers were used for communications.


Studio 23 (Click for a Picture)

Two CPS Emitron Cameras were used together with a Marconi rotary knob vision mixer. Sound mixing was via an AWA mixing console.

Studios 21 and 22 (Click for a Picture)

Studios 21 and 22 were virtually identical in design comprising an 80 feet x 60 feet floor space with a 25 foot ceiling. A Control Room and Viewing Gallery situated on level 2 of the building overlooked the studio floor. The major difference between the studios was the studio lights rigging systems which is detailed below.

Three Marconi Mk 3 Image Orthicon Cameras using 4.5 inch camera tubes were used in each studio. One camera was fitted to a camera crane, another on a pedestal and the remaining one on a tripod. This was used primarily for graphics. All cameras had a 4 lens rotating turret.

The Studio control room was fitted with an 8 input vision mixer, 3 inputs for cameras, 3 inputs from telecine; Telecine Line 1, Telecine Line 2 and Slides. Two Remote lines were available for OBs, Clock or other patchable inputs. The vision mixer was a 3 bus system; a cut bus for direct source switching and two effects busses where fades to black or dissolves could be made being controlled by a split fader lever system. Operation of effects was facilitated by transferring from the cut bus to an effects bus which one depending on the placement of the fader levers. The non-active effects bus was switched to the next input source and the faders moved to the other effects bus for a dissolve. The transition effect duration being controlled by the speed of fader movement. Fade to black was achieved by splitting the faders or where a spare mixer input was available by dissolving to a black input.

All inputs to the vision mixer were routed via a Cable Delay Room. Here drums of cables were used to ensure that all signals to the point of mixing arrived at the same time ie all signal paths were extended to match the longest cable run. The output of the Vision Mixer was fed through a Marconi Line Clamp Amplifier where the video synchronising signal was re-inserted to provide a clean un-interrupted output to air. Signal timing from the SPG in Master Control to say Telecine and back to studio had to match the SPG to Studio direct timing. Cable delays were the order of the day.

Audio was handled in a separate Control Room. An 8 channel AWA Audio Console with Programe and Audition busses was used as the main Mixing Console. Two "outrigger" 4 channel Consoles fed channels 5 and 6 on the main console to increase the main inputs and provide group fading facilities. In addition an adjacent AWA Consolette was used as an effects channel on input 7. This consolette was operated by a Grams Operator usually sourced from the Radio Sound Effects department. This 4 channel audio mixer allowed two Record Turntables and two reel to reel Portable Recorders to be used for replay to air. Channel 8 on the main console enabled a 6 button remote source selector to feed telecine or OB lines from Master Control into studio programmes. As all inputs were patchable the combinations were altered for differing programme requirements. By means of the 4 microphone inputs on each of the "outrigger" consoles it was possible to have fader control of a maximum of 16 microphone channels.

The Main Console had limited effects; cross fades. However reverberation was added by using a sound chamber. This was set up in a long narrow space between and above the two major studios. Being all concrete wall, floor and ceiling construction it was fitted with a loudspeaker at one end and a microphone at the other. This "Echo Chamber" microphone was fed back to the Studio Mixing Console where it was mixed back into the originating sound source. Fader settings determined the amount of echo effect.

Studio Lighting was controlled through a Strand Lighting Console. A modified Organ Console, it used tab switches to turn lights on or off either singularly or in groups. Dimmer Control was facilitated remotely using variable auto transformers. These comprised a mains operated externally wound transformer core which was traversed by two fader lever arms containing brushes which tapped across the external windings. High currents were involved as 500 watt, 1000 watt, 2000 watt and 5000 watt lamps were used in studio light fittings. As the copper windings and brushes wore down with use, a spectacular melt down occurred when the conductors could no longer handle the currents. The television lights in Studio 21 were supported from a fixed scaffold grid and adjusted in height using a panograph system. This allowed accurate placement of lights, particularly for Opera and Dramas, however extra rigging time was necessary as lights had to be physically moved for each set. Studio 22 used a motorised batten system which allowed the lights to be lowered to floor level for rigging and provided greater flexibility for a wider range of different productions.

Camera Control Units for each Camera were aligned, operated and adjusted before and during programmes. The stability of valve based technology and the drifting that occurred with camera movements, lighting temperature changes etc all contributed to variations in picture quality. It was normal practice to align the camera when it was switched on then realign it just prior to going to air. Alignment comprised using a RETMA Test Chart where aspect ratio, scan linearity (test circle) and resolution could be adjusted for optimum performance. Vision levels were set to 1 volt peak to peak with black level set up at 7.5% above blanking level. Flesh tones (in monochrome) were managed at approx 70% of vision level. During the programme a preview switcher was used to switch between the cameras to maintain level balance to minimise severe balance transitions.

Engineering Store and Workshop (Click for a story)

Virtually all television equipment was imported and spare parts could take a long time to purchase and replace. An Engineering Store was maintained holding some spares which were extensively used as well as parts recommended by the manufacturers to be held in case of, but in fact never used. Equipment failures were often mechanical in nature and the Engineering Workshop provided facilities to manufacture, modify and develop items particular to the broadcasting application. Metal presses, benders, lathes and drill presses, provided basic assembly operations and these were complemented by a precision workshop, where film camera and projector shutter mechanisms could be maintained without the need for expensive overseas replacements. Indeed the Studio Dimmer Transformers were rewound in the Workshops providing a quick turn around and the need for less spares.

Studio 20 - Presentation (Click for a Picture)

A small presentation booth known as Studio 20 permitted voice overs to link programme segments and housed the Presentation Officer who was responsible for coordinating all programmes. It was normal for programmes to be planned for hourly or half-hourly time slots. The ABC always programmed to the top of the clock. Local programmes were made to precise durations based on the half hour timings with perhaps time for a station ident with voice over to announce the next segment. Imported programmes were usually of 25 minute duration allowing 5 minutes for commercials to be interleaved during the programme. As the ABC was non commercial the 5 minute time slots were filled with an interlude. This invariably came from telecine, often a 35mm film replay. Initially these segments came from the BBC with items such as "The Great Tit at home" featuring UK bird life or the "Changing of the Keys" covering the ceremony of the handing over of the palace keys by Her Majesty's guards. Ultimately Australian 16mm film segments were used featuring local scenery with a musical sound track. Live presentations were then used typically with an announcer sitting in a lounge chair next to a floral arrangement giving a programme rundown.

Film Operations

16 mm Cine cameras, mostly Arriflex, were used for news and external inserts in studio productions. Processed Film was then edited to meet the programme requirements. Film eiting benches were used fitted with either simple viewer/splicers or as technology advanced elaborate synchronisers.

In the 50s editors had no way of looking at film except with a big stand alone viewing machine like a Moviola or an English Acmade. Later the ABC had German flat bed editing machines called Steenbecks.

A typical Film Editing Bench as used in the ABC enabled basic editing of cut and splice. Often accompanied by a small optical viewer it was good for quick editing of short mute news stories. Keeping synch on longer productions with interviews and sound effects was always a problem using these viewers.

The Synchronizer enabled all film clips to run locked together while various editing tasks were performed.

Synchronizers have been in use since the beginning of film making in the early 1900s for negative matching. In this function the negative is cut on the synchronizer and spliced in exactly in the same place the cut work print. Thus a new clean print can be struck from the newly cut negative free of splices ready for exhibiting.

When sound came along the synchronizer was used to synchronize image to sound for editing. They were called synch sound rushes.

In synching rushes the sound clapper noise is lined up with vision of the clapper shutting. They run locked together in the synchronizer till the next clapper arrives and so on. Sound recording takes longer to slow down and start up than the intermittent movement of a movie cameras. So sound is usually longer than the image. Sound is cut off at each camera stop to maintain synch. If there is mute image the sound is spaced out till the next sound slate comes along.

The last task for a synchronizer is to enhance the sound track of a production. Sounds like music, sound effects and narration are on there own tracks and locked together in synch with the image. This is called track laying. Eventually all sound tracks are mixed into one track. That single sound track is printed onto the side of the new clean copy of the film. This is called a married print

The first Acmade viewer synchronizers didn't make it's appearance till the early 60s. When they arrived pictures could be viewed on the bench while keeping the magnetic sound heads locked with the picture head. It meant everything was in synch as it was viewed. This was a big break through. Suddenly portable bench editing was possible.

A Wet Film Splicer is shown at the back of the picture. A Wet splicer works on the principle of joining two scenes together with film cement. First the emulsion and the other protective coatings are scraped off till the raw base is left. Then film cement is applied and the film joined together. The film base is welded together not glued.

Before splicers were invented film was scraped then cement applied and carefully the sprocket holes were lined up by eye and held down. A skill in itself.

The wet splicer made this job a lot easier with guide posts to line sprocket holes The film scraping is more accurate. Film cement applied and the splicer shut on the film. Within 20 seconds the film is bonded as one piece of film, perfectly lined up.

This type of splicer predates the modern film tape splicer which was invented in the 60s. It was a great advanced in film editing. No longer were two frames of image lost every time a change in editing was made.

Wet splicers and synchronizer are still used to day but only for negative matching feature films and film documentaries.

This is where wet splicers and synchronizer started 100 years ago and there still going. That is till Hollywood goes completely digital which is no too far off.

Transmitter (Click for a Picture)

Official transmissions began in Sydney on 5th November, 1956, on ABN Channel 2. Test transmissions preceded this using mainly a test pattern.

The station operated on the frequency of 63-70 megacycles, transmission being provided by 5Kw vision and 1Kw audio standby transmitters, radiating from temporarily erected mast (affectionately known as little toot) to give an effected radiated power of 16Kw vision and 3.2Kw sound.

When the Postmaster-General’s Department completed the installation of the main transmitters and mast, these were brought into service in August, 1958. The permanent mast was approximately 504 ft.(154 m) high, and provided an effective radiated power of 100 Kw for the vision and 20 Kw for the sound carrier.

 

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