. QST . amic rotary switch. Powertransformer ratings are discussed in the text. it), I came up with the following gimmick whichmay be of interest to some rig builders. Originally I planned to put a pair of 807s orequivalent tubes in the final, and so provided a600-volt 250-ma. power supply for them. I alsoplanned to use a pair of the same tubes as modu-lators, and provided a separate 600-volt supply for them. After both power sup-plies were installed on the chassis and working, Iconsidered the fact that half of my available was unused on A little thought evolvedthe
. QST . amic rotary switch. Powertransformer ratings are discussed in the text. it), I came up with the following gimmick whichmay be of interest to some rig builders. Originally I planned to put a pair of 807s orequivalent tubes in the final, and so provided a600-volt 250-ma. power supply for them. I alsoplanned to use a pair of the same tubes as modu-lators, and provided a separate 600-volt supply for them. After both power sup-plies were installed on the chassis and working, Iconsidered the fact that half of my available was unused on A little thought evolvedthe circuit showm in Fig. 3. Basically, the control is a 3-pole 3-positionswitch. In the phone position it runs the from one 600-volt supply, and the modu-lator from the other. In the position it re-moves plate power from the modulators andshorts out the secondary of the modulation trans-former. In the third position, called hi-power ,it places the two 600-volt supplies in series, giving. Fig. 4 ■— Circuit diagram of the transistorized oscilla-tor. Li is the plate winding of a broadcast-oscillator coil(Meissner 14-1058 or equivalent). This circuit may be used as a signal generatorfor ham frequencies, calibration purposes or as anexternal for a short-wave receiver having nobeat oscillator of its own. Simph^ tune the tran-sistor circuit approximate!} to that of a sig-nal. This creates a beat with the incoming need to alter the receiver. The oscillator uses less than ma. at volts,but it can be driven safely with up to 6 volts. — Nathaniel Queen, W2CPA ANOTHER SOURCE OF COIL FORMS Two TYPES of vials, used by druggists for pack-aging pills, make excellent coil forms of theinexpensive variety. Complete with plastic capsthat may be used as mounting feet, the vials October 1955 45 come in two convenient sizes. One has a diameteiof slightly less than Jg inch and the other is aneven 1 }s inches in diameter. Both types provide awuiding
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectradio, bookyear1915
