We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
Radio Broadcast
justify this would be where the atmospheric noise was not very great and where it was desired to obtain the very limit that could be gotten from a receiving system. Or, it might be that the receivers were poorly located, so far as collecting sufficient energy for their operation is concerned, yet the noise level might be very low. In either of these cases it would be possible to add a stage of R. F. amplification before the first detector tube, which would involve but one additional tuning adjustment. This adjustment would be comparatively sharp and the addition of this amplification is not recommended until the builder has operated his set for some time and is entirely familiar with its operating characteristics. This is because with three tuning dials the set would be so sharp that it would be extremely difficult to tune it without knowing where at least two of the dials should be set for a given wavelength.
The circuit for this amplification is given in Fig. 7 and the only additional equipment necessary to construct it would be an oscillator coupler, as described in the previous section, the tube with its socket and rheostat, the tuning condenser, and a balancing condenser.
The entire amplifier could be housed in a small box which would go at the loop end of the set with three binding posts to connect it to the set and three binding posts for the
loop. It would also be necessary to bring out posts for the A and B batteries as shown in the drawing.
It will be seen that this circuit is practically the same as that of the first detector, except that the grid condenser and leak and oscillator coupling coil have been omitted.
In the plate circuit of this R. F. tube, the coupling coil of an oscillator coupler is connected. The stator windings of the coupler are brought to three binding posts on the panel of this unit and are in turn connected to the three binding posts intended for the loop on the set itself. The oscillator coupler then performs the function of the R. F. transformer. Its two stator coils with their center leads joined, form the secondary circuit, the coupling coil acting as the primary. The balancing condenser in this case is not critical as in the first detector circuit of the super and may be set practically all the way in without oscillation occurring in the R.F. stage. This condenser acts almost entirely as a neutralizing condenser, its purpose being to sharpen the tuning of the loop connected in the R. F. stage and to prevent oscillation.
The same batteries may be used for this unit as are used for the set itself, and any standard type of tube may be employed in the circuit.
FORCE OF RADIO HABIT
The Doctor: "H'm! that's strange, Cuba ought to be on now!"