If you can not afford mobile television station (instead of afterword)

By Michael Zhitomirskiy

It is not a secret that almost all TV companies just dream about having a mobile television station but only few of them may afford it. Especially, this can be said about small regional TV companies whose budget does not allow even timely maintenance and update of the necessary equipment inventory. But this does not mean that these companies cannot do multi camera shooting, considering the fact that it is not required very often. Usually, it is required during events of municipal or regional standard: concerts, game shows, beauty contents, etc., election campaigns being most important. Often, TV companies do not have studios available of holding, for example, a round-table discussion between all candidates. Usually, similar debates take place in a hall of some establishment. But pre-election is known as one that allows regional TV companies to rectify their budget and sometime to better their financial situation greatly. So, we hope, variant of multi camera system made up from so-called “improvised means”, described below, will come in handy.

The subject of this article is taken from the experience of the author. The main point is that it is possible to realize multi camera shooting having either usual inexpensive two-/three-input video mixer (for example, Panasonic MX-12 or even AWE-5), and also video tape recorders with built-in input selectors, or simple commutator, even key-driven. Some other equipment will be necessary, but we will talk about it later. This offer being addressed to low-budget TV companies, we will base on the operating in S-VHS or DV format and using Y/C or composite signal. Of course, quality will correspond to the selected signal type, but the experience shows that this is enough for such level.

The idea is that video tape recorders or commutators are primary signal selectors, video mixer being final selector. Program signal, later sent either for recording or directly on the air, is taken from the final selector. Structural scheme of such extempore mobile television station is shown in the picture. Such scheme allows operating with non-synchronized signal sources. Their synchronization is realized already in video mixer, before this it just not required. In case mixer with outer synchronization is used, one of the cameras is switched directly to reference input, all the others being switched via commutator to another one. In case mixer without outer synchronization is used (with built-in frame buffer), the scheme of switching sources is not important. However, the first case has one disadvantage: to avoid detriment, all transmissions from one camera to another should be done through picture from the camera switched to reference mixer’s output. But there is a way out: one must simply set this camera for shooting general picture. The situation gets less complicated if mixer employs three inputs. It is only necessary to send stable signal (e. g. from decoder) onto one of the inputs and then use it only for titling. Two other inputs receive signal from commutators (video tape recorders). The second case does not restrict director’s possibilities anyhow.

As experience shows, there is no degradation of picture quality even with cables (of radio-frequency coaxial type) of up to 50 m (on operating through composite channel). It is only necessary to provide reliable fastening of cable’s joints to control panel (video tape recorder/commutator) and camera. Receiving part does not show any problems usually. One should simply make sure to fasten the tail of cable with the help of clip, sticker, or, by binding it to leg of the table where the equipment is placed. From camera’s site it will be necessary to make something like commutation box. This box is fixed on operator’s strap. It must be equipped with video joints (input and output). Output joint is attached with main cable, input joint is attached with quite short cable transiting signal from camera to the box. In case composite signal is used, it is better to use bayonet joints. In case Y/C signal is used, there may be used either two bayonet joints (one for brightness signal, the other for color-difference signal) or standard male joint but with additional point for attaching cable to the box. All this provides reliable joining and some movement freedom of operator who may unfasten the cable at any point and continue shooting in independent mode (for example, in the wings, in foyer, etc.).

Simplified scheme of a multicamera complex based on three input video mixer

But commutation box must be equipped not only with video joints, for director has to commutate with operators. In this case, the question is about one-way communication: operators hear director who, in his turn, does not hear operators. As one can understand, the box must employ joints for audio cable and headphones. Usual pair may be used as cable. It is important the pair to be strong and flexible enough. Audio cable is fastened to video cable with the help of adhesive tape every 0,5…0,8 m. For formatting sound signal of service traffic one can use either channel of audio mixer, if it is possible, or additional mixer, amplifier, or even simple tape recorder.

Cameras’ signal controller is worth additional mentioning. In 1993, when the author of this article was taking part in creation and operating of this multi camera system (it is difficult to call it mobile television station), nobody even knew about tiny modules of Kramer Tools type. Thus it was impossible to control signals of all cameras at the same time. One had “to spy” on picture from off-line cameras and to correct movements of operators. The scheme was simple: number of control monitors corresponded not to number of cameras, but to number of primary commutators. Now the task is simpler. It is enough only to employ inexpensive amplifier-splitters of video and audio signals for controlling pictures of each camera. We think, it is better to use video tape recorders as primary commutators, for in this case it is possible to insert previously prepared fragments (logos, spacing, trailers) into ready program.

There is no need to give detailed description of audio channel for it is standard. Microphones and audio devices (such as CD-players, audio tape recorders, etc) are used as signal sources.

Of course, such scheme is far from being perfect. It has many disadvantages and shortcomings. Still it has real advantage: it costs practically nothing and allows using already existing equipment. Besides, such system allows personnel to acquire practical skills that will come in hand during operating a real valuable mobile television station.

The editors of “625” will be glad to review experience of our readers and the most interesting materials will be published in our magazine. This will probably help many people to solve their daily TV production problems.