User manual RACAL RA-217

[. . . ] AMPLIFIER - RIGHT SIDE FIG. 22 - 100 kc/s I. F. AMPLIFIER - LEFT SIDE FIG. 23 - AUDIO STAGES AND POWER SUPPLIES RA. 117 RECEIVER - SCHEMATIC DIAGRAM BACK TO RECEIVERS AND SCHEMATICS !BACK TO RA. 117-RECEIVER PAGE (FINNISH) ! RACAL RA. 117 SPECIFICATIONS TECHNICAL SPECIFICATION RACAL Type RA117 ----------------------------TECHNICALSPECIFICATION ----------------------------------------------------------------Frequency range: 1 - 30 Mc/s Stability: Afterwarm-up, overall drift is less than 50 c/s per hour under conditions of constant supply voltage and ambient temperature. Input impedance: (1) Wideband 2000-ohms approx. [. . . ] (4) Responses at 3. 800 and 4. 000 Mc/s due to second v. f. o. (5) Responses of 1. 7 and 3. 4 Mc/s due to 1. 7 crystal oscillator break-through. (6) Response of 3. 2 Mc/s due to 6 Mc/s break-through. CHECKS FOR SPURIOUS RESPONSES 3. Spurious responses are measured relative to receiver noise in the following manner:When response is located, the receiver is de-tuned from it just sufficiently to render the beat inaudible. gain is then adjusted to provide a convenient noise reference output (1mW) and the receiver retuned to the spurious signal for maximum output. The dB rise in audio output is a measure of the spurious signal level relative to receiver noise. Standard conditions of test: No connection to aerial socket System switch to MAN. RACAL RA. 117 SPURIOUS RESPONSES R. F. /I. F. 37. 5 MC/S BREAK-THROUGH TO THIRD MIXER 4. This response will be indicated as a beat note which varies rapidly in frequency with respect to the KILOCYCLES scale, i. e. a change of 1 kc/s on the scale results in a much larger change in the note. It will also move along the KILOCYCLES scale if the MEGACYCLES dial is adjusted slightly. Ascertain that bonding is effective between the 1. 7 Mc/s oscillator/mixer chassis and the first v. f. o. chassis. RACAL RA. 117 VALVE DATA VALVE DATA INTRODUCTION 1. Details of valves used in the receiver are given in Tables 1 and 2 overleaf. The location of valves is shown in fig. 8 and valve base connections are given in the circuit diagram. Voltages were obtained from a B9A or B7G stand-off valve base using a 20, 000 ohms/volt meter on the optimum range in each case. Valve pin numbers are indicated in brackets in Table 2. The receiver was set as follows:(1) SYSTEM switch to MAN. (5) SYSTEM switch to CAL in order to check V13 and V15 only. TABLE 1. Pin 6AK5W 6ES8 6AS6 6BA6 6688 12AT7 6BE6W 6AL5 6AQ5 No. M8100 ECC189 EF93 E180F ECC81 EB91 1 Grid1 Anode2 Grid1 Grid1 Cathode Anode2 Grid1 Cathode1 Grid1 2 Cathode Grid2 Cathode Grid3 Grid1 Grid2 Cathode Anode2 Cathode & Grid3 & Grid5 3 Heater Cathode2 Heater Heater Cathode Cathode2 Heater Heater Heater 4 Heater Heater Heater Heater Heater Heater Heater Heater Heater 5 Anode Heater Anode Anode Heater Heater Anode Cathode2 Anode 6 Grid2 Anode1 Grid2 Grid2 I. C. Anode1 Grid2 Screen Grid2 &4 7 Cathode Grid1 Grid3 Cathode Anode Grid1 Grid3 Anode1 Grid1 8 - Cathode1 - - Grid3 Cathode1 - - & Screen 9 - Screen - - Grid2 Heater - - tap Base B7G B9A B7G B7G B9A B9A B7G B7G B7G RACAL RA. 117 VALVE DATA TABLE 2. [. . . ] assembly is necessary in order to obtain acces to one of the six securing screws. (5) Remove screw securing cable cleat situated adjacent to 150mH choke assembly on underside of i. f. cableform from terminal on adjacent 12-way tag strip. (7) Withdraw red-white lead from cableform. [. . . ]