From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Instructions for spot tuner adjustment and reducing motor noise interference on a car radio.
| Identifier | ExFiles\Box 168b\1\ img062 | |
| Date | 1st January 1938 guessed | |
| Turn the receiver to maximum volume, by turning the volume control all the way to the right. SET THE ACCOUSTINATOR to "COUNTRY" and "VOICE" POSITIONS. Tune in a WEAK station, at approximately 600 K.C. on the dial. With a screw driver, adjust the antenna trimmer screw, which is located on the front of the receiver in the lower left hand corner, until maximum volume is reached. Retune the signal and again adjust the antenna trimmer to maximum volume. SPOT TUNER ADJUSTMENT Now that the antenna circuit of the receiver has been adjusted to match the car antenna, the SPOT TUNER can be set to facilitate the tuning of favorite stations accurately. BEFORE "SETTING" ANY STATION, TURN THE SET ON AND LET IT WARM UP FOR NOT LESS THAN 10 MINUTES to assure all electrical circuits reaching a constant operating temperature. Loosen the set screw that holds the tuner housing to the receiver, and slip the housing up the flexible tuning control shaft several inches, exposing the SPOT TUNER mechanism, which consists of a small ball bearing, a brass raceway in which it moves, and a slotted retainer clip, which acts on its guide. Set the pointer in the control head for correct dial calibration, as outlined in the control head instructions. SET THE ACCOUSTINATOR TO "STREET CAR," then tune in AS ACCURATELY AS POSSIBLE, one of the desired favorite stations. Any station too weak to be heard in the "Street Car" position is too weak to "set" on the SPOT TUNER. With a pair of slip jaw gas pliers, one jaw of which rests firmly on the small ball bearing, the other jaw of which rests on the bottom of the unit, apply enough pressure on the ball to force an indentation in the brass raceway in which it moves, (Fig. 3.) Proceed to set other favorite stations in the same manner. You can "set" as many favorite stations as you wish, although for maximum enjoyment of the device, we recommend that you "set" only the limited number of more powerful stations that are regularly depended on for radio entertainment in your locality. We suggest a maximum of six stations. DO NOT "SET" WEAK STATIONS, since this would lessen the value of the device to your customer. A few stations can be memorized and tuned rapidly, whereas, too many stations cause confusion. When all desired stations have been set, slip the tuner housing down over the flexible tuning shaft, into its proper position, tighten the set screw securely, and tighten the knurled clamp nut until the flexible tuning shaft housing is held firmly. BEFORE APPLYING PRESSURE WITH THE PLIERS, BE SURE THE STATION IS TUNED ACCURATELY. The raceway has a double track. Therefore, should the customer desire to reset the SPOT TUNER to a new series of favorite stations, it can be done by moving the ball bearing over to the second track. To do this, turn the condenser gang to full mesh (ball bearing at extreme end of raceway) and with a pointed instrument, force the ball bearing into the adjoining groove. A THIRD SETTING CAN BE MADE ONLY BY INSTALLING A NEW RACEWAY. Order part No. 1X4497 from your Motorola Distributor. Fig. 3 IGNITION INTERFERENCE Install the distributor suppressor which is included in the accessory package. Mount the generator condenser on the generator frame and connect the pigtail to the battery contact on the generator cut-out. ADDITIONAL MOTOR NOISE HINTS When checking the car for motor noise, clamp the hood down tight with the hood hasps. When a top antenna is used, it may be necessary to install Motorola hood bonds at the shoulders so that the hood makes a good ground to the cowl of the car. In severe cases of motor noise on a top antenna, be sure that the shielded staff is grounded above the windshield as well as at the cowl. If the position of the feet in either the driver's or passenger's position, causes motor noise, a piece of copper screen should be placed under the floor mat and grounded to the car body. With an under-car antenna, it may be necessary to bond the muffler or the transmission housing to the frame of the car. CAUTION: Make all bonds exceedingly short and heavy—otherwise they will prove ineffective. Noise from electric gas gauges may be cured by inserting a dome lite filter in series with this lead near the gas tank. In some cases, it may be necessary to install an ammeter condenser from the ammeter to ground. For severe cases of the static use a "Clipper" or top antenna. | ||