GBC UT6820 YEAR 1976.

The GBC UT6820 is A B/W 20 Inches screen Portable with 6 programs preselection with potentiometric search tuning and incorporated antenna.

The mechanical turret approach to television tuning has been used almost exclusively for the past 60 years. Even though replete with the inherent disadvantages of mechanical complexity, unreliability and cost, such apparatus has been technically capable of performing its intended function and as a result the consumer has had to bear the burdens associated with the device. However, with the " recent "  Broadcast demands for parity of tuning for UHF and VHF channels, the increasing number of UHF and cable TV stations have imposed new tuning performance requirements which severely tax the capability of the mechanical turret tuner. Consequently, attempts are now being made to provide all electronic tuning to meet the new requirements.

The invention relates to a tuning unit with bandswitch for high frequency receivers, especially radio and television receivers, having a potentiometer system for the control of capacity diodes, the said potentiometer system consisting of a plurality of parallel resistance paths along which wiper contacts can be driven by means of screw spindles disposed adjacent one another in a common insulating material housing in which a bandswitch formed of metal rods is associated with each tuning spindle.
In these tuning units, the working voltages of the capacity diodes in the tuning circuits are recorded once a precise tuning to the desired frequency has been performed. A potentiometer tuning system has great advantages over the formerly used channel selectors operating with mechanically adjustable capacitors (tuning condensers) or mechanically adjustable inductances (variometers), mainly because it is not required to have such great precision in its tuning mechanism.
Tuning units with bandswitches formed of variable resistances and combined with interlocking pushbuttons controlling the supply of recorded working voltages to capacity diodes are known. Channel selection is accomplished by depressing the knobs, and the tuning or fine tuning are performed by turning the knobs. The resistances serving as voltage dividers in these tuning units are combined into a component unit such that they are in the form of a ladderlike pattern on a common insulating plate forming the cover of the housing in which the tuning spindles and wiper contacts corresponding to the variable resistances are housed. The number of resistances corresponds to the number of channels or frequencies which are to be recorded. The wiper contact picks up a voltage which, when applied to the capacity diodes determines their capacitance and hence the frequency of the corresponding oscillating circuit. The adjustment of the wipers is performed by turning the tuning spindle coupled to the tuning knob. By the depression of a button the electrical connection between a contact rod and a tuning spindle is brought about and thus the selected voltage is applied to the capacity diodes. Since the push buttons release one another, it is possible simply by depressing another button to tune to a different receiving frequency or a different channel, as the case may be.
 Moreover, using this arrangement, the only indication--during adjustment--of which channel is selected is by station identification.
The use of voltage-variable diode-capacitors, such as varactor diodes, permits the electronic tuning of radio receivers and television receivers by the use of DC control voltages; so that the tuning elements no longer need to be intimately associated with the tuner. Thus, the tuned circuits of the tv receivers may be located remotely from the devices used to provide the necessary DC tuning voltages. In addition, the compact size of the voltage-variable diode-capacitor tuning circuits makes it desirable to use such tuning circuits in many tv applications which formerly used mechanically adjusted variable capacitors or the like as the tuning elements.

To employ voltage-variable diode capacitors in pushbutton tvs, however, especially in multiband pushbutton tv sets , a problem exists in providing a "memory," so that operation of a pushbutton will provide consistent tuning of the tv receiver to the station which is to be selected by that pushbutton. In addition it is necessary to provide some means for providing the initial tuning of the tv receiver for each pushbutton location in a manner which is reliable and inexpensive.



GBC is a commercial brand with a long tradition and solid experience. It history begins in 1958, when Gian Bruto Castelfranchi (G.B.C.) established the company, with the aim of conquer the market.GBC is the acronym for Gian Bruto Castelfranchi, who founded the company in 1958 in order to commercialize instrument accessories and related material.
It is his son Jacopo, however, who made GBC the biggest company in Italy for the commercialisation of electronic materials and devices.

Jacopo joins his father's company in 1946, starting to increase the number of represented products and expanding in the field of electronic components, tubes, passive components and various equipment such as tape recorders and turntables.

The company expands and diversifies and in 1957 the Selezione di Tecnica Radio TV periodical is born, for which is created the J.C.E., Jacopo Castelfranchi Editore who was also the editor
of a monthly Magazine "IL CINESCOPIO" with his technical director Amadio Gozzi.

Not to be confused with the Selezione Radio magazine, published from 1951.

In 1962 the head office is transferred to Cinisello Balsamo owing to a shortage of space.
In 1970, the magazine changes its name to Sperimentare Selezione di Tecnica Radio TV.
In 1970 it becomes a Sony distributor for Italy and it later creates a joint venture with it.
The sales points in Italy reach maximum expansion with over 150 shops.
GBC also designs and creates its own high-fidelity stereo systems and televisions.
In these years, GBC also commercialises assembly kits branded “High kit” and “Amtron”.
In the next few years, it also becomes an importer for Bang&Olufsen, Sinclair and Goldstar.
GBC is sold in 1980.

With these words we could define Kon.El.Co. S.p.A. The history of the society in fact is recent, but the competence and the experience baggage that this company is able to guarantee, defines this reality as a reliable distributor with a long commercial tradition. Founded in 1994, Kon.El.Co. S.p.A. developed immediately, earning the concession of well-known commercial brands. Subsequently the company has become a S.p.A. and since then has obtained great results, always more and more rewarding, that today define Kon.El.Co. S.p.A. as one of the leader society in the electronic branch. Since the beginning, GBC brand accompanies the success of Kon.El.Co. S.p.A., constituting the most important commercial project of the company.