1. CF351 F07 - 1 Unclassified 4 Hour Conference, W/ 7Hr PE1 Safety & Environmental Impact is “LOW” TIII:

2. CF351 F07 - 2 SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER Action: Given a schematic diagram, answer questions pertaining to Ckt operation, Transmitter & Receiver group concepts and signal tracing procedures. Condition: W/O References. Standard: Answer 7 of 10 written questions correctly as well as troubleshoot & locate a malfunction W/in 20 minutes. 20 seconds

3. CF351 F07 - 3 All electronic communications both in defense as well as the private sector are centered around the very basic transmitter & receiver groups. This lesson will concentrate on the Receiver group w/ an overview in a block diagram of the transmitter group. SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER Overview

4. CF351 F07 - 4 FM FM; Frequency Modulated The FCC, Federal Communications Commission grants all License, & call letter designations. 3 call letter stations were grandfathered in due to there existence before the establishment of the FCC in 1932. Transmitter Group SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER Overview; WLW Cincinnati OH. KLT Pittsburg Pa. AM AM ; Amplitude Modulated

5. CF351 F07 - 5 OSCILLATOR 1000 KHZ CW TRANSMITTER – Generates a continuous wave (CW) carrier frequency with an additional signal intelligence impressed upon it, thus becoming an Amplitude Modulated (AM) signal. Once powered up the AM signal is put on the air as transmission RF waves via an antenna. SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER TRANSMITTER GROUPOSCILLATOR TRANSMITTER GROUP; OSCILLATOR Modulator

6. CF351 F07 - 6 SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER TRANSMITTER GROUPMODULATOR TRANSMITTER GROUP ; MODULATOR A.Input acquired from OSCILLATOR (1000 KHZ) B.A 2 nd signal from transducer is mixed with 1000 CW to produce and Amplitude Modulated (AM) signal or Carrier Transmission. Modulator or Mixer OSCILLATOR 1000 KHZ CW TRANSDUCER {Microphone} PWR Amp

7. CF351 F07 - 7 SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER TRANSMITTER GROUPPOWER AMPLIFIER TRANSMITTER GROUP ; POWER AMPLIFIER Hometown USA A.Power Amplifier Boosts the AM signal up and applies it to the Antenna. B.The AM – RF energy is transferred to the atmosphere in the form of Radio Frequency (RF) radiation. POWER AMPLIFIER Modulator or Mixer OSCILLATOR 1000 KHZ CW TRANSDUCER Dear Ma Receiver

8. CF351 F07 - 8 SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP ANTENNA RECEIVER GROUP; ANTENNA RF RADIATION Antenna (aerial) Is the device that intercepts the AM electromagnetic radiation waves. As the waves pass and are cut by the aerial, small amounts of current will be induced upon it. Hometown USA Tuner USPS

9. CF351 F07 - 9 Hometown USA ANTENNA TUNER 1000 KHZ A: Selects one signal from the many on the aerial by tuning a Parallel LC Tank circuit to resonate @ 1000 KHZ. B: The tuner is capable of tuning-in all the AM frequencies with in the AM spectrum of 540 KHZ – 1610 KHZ. C: The selected frequency of 1000 KHZ is applied to the converter or mixer. SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP TUNER RECEIVER GROUP; TUNER Tuner PC 38

10. CF351 F07 - 10 Tuner O Antenna T3 T2 Q1 3 2 4 5 1 7 6 T1 R2 6.2 K  R1 47 K  R3 22 K  C3.01  f R4 1 K  C1 A C1 B TIII: SUPERHETERODYNE RECEIVER Antenna Tuner RECEIVER GROUP; PC Antenna & Tuner. PC 38 Local Osc

11. CF351 F07 - 11 PC 38, LO SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP Local Oscillator [LO] RECEIVER GROUP; Local Oscillator [LO] CONVERTER or MIXER LOCAL OSCILLATOR 1455 KHZ TUNER 1000 KHZ Hometown USA 1. The LO Signal output is always the Tuner Frequency, Plus 455 KHz Regardless of what AM signal is tuned. 2. It is tuned simultaneously with the RF Tuner. 3. The output would be 1000 + 455 = 1455 KHZ CW. 4. The output of 1455 KHZ is sent to the Converter or Mixer.

12. CF351 F07 - 12 Converter / Mixer SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP Local Oscillator [LO] RECEIVER GROUP; Local Oscillator [LO] PC 38 Tuner LO O Antenna T3 T2 Q1 3 2 4 5 1 7 6 T1 R2 6.2 K  R1 47 K  R3 22 K  C3.01  f R4 1 K  C1 A C1 B

13. CF351 F07 - 13 PC 38, Mixer SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP Converter / Mixer RECEIVER GROUP; Converter / Mixer MaUSA The 1000 KHZ from the Tuner is heterodyned with a 2 nd signal from the Local Oscillator [1455 KHz] to produce 4 different output frequencies. F1 RF F2 LO F2+f1 SUM f2-f1 DIFFERENCE 1000 KHZ 1455 KHZ 2455 KHZ 455 KHZ or CONVERTER MIXER RF TUNER 1000 KHZ LO 1455 KHZ INTERMEDIATEFREQUENCY(IF) Hometown USA

14. CF351 F07 - 14 IF Amp TIII: SUPERHETERODYNE RECEIVER Converter / Mixer RECEIVER GROUP; Converter / Mixer PC 38 Tuner LO Converter O Antenna T3 T2 Q1 3 2 4 5 1 7 6 T1 R2 6.2 K  R1 47 K  R3 22 K  C3.01  f R4 1 K  C1 A C1 B 455 KHz

15. CF351 F07 - 15 PC 39, IF Amps SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP IF Amplifier RECEIVER GROUP; IF Amplifier IF amplifier has the most receiver gain and is made up of 2 cascaded high gain amplifiers tuned to 455 KHZ. Sensitivity and bandwidth [T4 & 5] are determined by this stage. The [IF] output is sent to the detector (demodulator). IF Amplifier 455 KHZ or CONVERTER MIXER RF TUNER 1000 KHZ LO 1455 KHZ MaUSA PC 38 PC 39

16. CF351 F07 - 16 Detector TIII: SUPERHETERODYNE RECEIVER IF Amplifiers RECEIVER GROUP; IF Amplifiers PC 39 T4T5 Q2Q3 R5 56 K  R7 10 K  R8 47 K  C4 10  f T3 s Operate Test R 11 2.7 K  R 13 100 K  R 12 5 K  15 C 11.05  f D 1 17 1013 912 1114 8 C6 10  f 1 st IF Amp 2nd IF Amp Detector O C8 C7R6 C9C10 R9 R10 38 card

17. CF351 F07 - 17 PC 39 Detector SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP DETECTOR DEMODULATOR RECEIVER GROUP; DETECTOR OR DEMODULATOR Rectifies the modulated signal, then filters out the 455 KHz Leaving only the audio frequency or intelligence of 50 Hz – 20 KHz Which is sent to the AF amplifiers. Detector IF amplifier 455 KHZ AM or CONVERTER MIXER RF TUNER 1000 KHZ LO 1455 KHZ MaUSA Your Favorite Son 455 AMRectifiedFiltered PC 38 PC 39

18. CF351 F07 - 18 TIII: SUPERHETERODYNE RECEIVER DETECTORDEMODULATOR RECEIVER GROUP; DETECTOR or DEMODULATOR PC 39 38 card Filter O T4 T5 Q2Q3 T3 s Operate Test R 13 100 K  R 12 5 K  15 C 11.05  f D 1 Detector 17 1013 912 1114 8 C6 10  f 1 st IF Amp 2nd IF Amp Detector C4 10  f R5 56 K  R7 10 K  R8 47 K  R11 2.7 K  R6 C1R9C9R10C10 C8 AGC

19. CF351 F07 - 19 PC 39, AGC TIII: SUPERHETERODYNE RECEIVER AVCAGC RECEIVER GROUP; AVC or AGC Automatic Volume Control or gain control is taken at the detector (demodulated and fed back to the first IF amplifier base. Required to overcome atmospheric and terrain conditions that adversely affect signal strength between the transmitter & receiver. AVC or AGC Detector IF Amplifier 455 KHZ AM or CONVERTER MIXER RF TUNER 1000 KHZ LO 1455 KHZ PC 38 PC 39

20. CF351 F07 - 20 All Ckt PC 39 TIII: SUPERHETERODYNE RECEIVER AVC or AGC RECEIVER GROUP; AVC or AGC PC 39 R6 C1R9C9R10C10 C8 O T4 T5 Q2Q3 T3 s Operate Test R 13 100 K  R 12 5 K  15 C 11.05  f D 1 AVC 17 1013 912 1114 8 C6 10  f 1 st IF Amp 2nd IF Amp Detector R5 56 K  R7 10 K  R8 47 K  C4 10  f R 11 2.7 K  PC 38

21. CF351 F07 - 21 TIII: SUPERHETERODYNE RECEIVER 1 st 2 nd IF Amp, Detector, AVC AGC. RECEIVER GROUP; 1 st & 2 nd IF Amp, Detector, AVC or AGC. PC 39 38 card Filter O T4 T5 Q2Q3 T3 s Operate Test R 13 100 K  R 12 5 K  15 C 11.05  f D 1 Detector AVC 17 1013 912 1114 8 C6 10  f 1 st IF Amp 2nd IF Amp Detector R5 56 K  R7 10 K  R8 47 K  C4 10  f R 11 2.7 K  R6 C1R9C9R10C10 C8 PC 39 Audio Amps

22. CF351 F07 - 22 PC 40 TIII: SUPERHETERODYNE RECEIVER AUDIO AMPLIFIER RECEIVER GROUP; AUDIO AMPLIFIER AUDIO Amplifiers AVC OR AGC Detector IF Amplifier 455 KHZ AM or CONVERTER MIXER RF TUNER 1000 KHZ LO 1455 KHZ 3 stages: Audio preamp Audio driver Audio push- pull AUDIO AMPLIFIER PC 38PC 39PC 40

23. CF351 F07 - 23 Pre Amp Audio Pre Amp Driver Audio Driver Push Pull Audio Push Pull Q4 Q5 Q6 Q7 18 21 19 20 24 27 31 29 28 O 22 23 25 26 T6 T7 R18C13 C14 R15 R14 R17 R16 C12 R20 R19R21 C15 D2 R25 R24 R23 C16 E 30 TIII: SUPERHETERODYNE RECEIVER AUDIO AMPLIFIER RECEIVER GROUP; AUDIO AMPLIFIER PC 40 Trouble Shoot

24. CF351 F07 - 24 SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER RECEIVER GROUP Trouble shooting procedure. RECEIVER GROUP; Trouble shooting procedure. 2 4 3 18 20 19 21 23 22 27 31 26 24 25 29 9 11 10 12 14 13 15 PC38 PC39 PC40 Tone, PC 40 OK Tone, PC 38, 39, 40 OK Tone, PC 39, 38 OK 1 st  2nd3rd No Tone PC 40 Malfunctioning No Tone PC 39 Malfunctioning No Tone PC 38 Malfunctioning Lesson Test

25. CF351 F07 - 25 Answers 1-9 SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER Review Questions Review Questions; 1.Where does heterodyning take place in the receiver taught? ________________ 2.The IF amplifier is tuned to the __________ frequency of _______ KHz. 3.What are the block diagram stages of a Super heterodyne receiver? __________________________________ ___________ 4.What components make up the Local Oscillator & Feedback? ___, ____, ____. 5.What is the propose of the AVC [AGC] Ckt in the receiver? ______________ 6.What are the two actions needed to Demodulate an AM carrier? _______________,_____________. 7. What type of coupling is used in the RF & IF section of the Super-Het-Receiver discussed in this lesson? _____________________ 8.T6 Secondary in the audio amplifier is center tapped to provide 2 signals that are the ________ in amplitude and the ____________ in polarity. 9.What is the purpose of Q5 Driver Amp in PC 40? _____________________

26. CF351 F07 - 26 Answers 10- 21 SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER Review Questions Review Questions; 10.What is the frequency range of a standard AM broadcast receiver? _____________ 11.Frequency conversion can handled by two stages, or only one. What are they called?____________,________________. 12.After a receiver is properly aligned, it should have maximum _______ & ________ 13.What is the frequency of the Local Osc, [LO] ? __________ 14.What is the main use of the Audio output Transformer [T7] ? _________ _______ 15.What section of a super heterodyne receiver provides the most gain? _____ 16.Where & what is the first test in troubleshooting an inoperative receiver ? _____, ____________ _______________ 17.When troubleshooting the superhet receiver, which section [card] do you check first? _____________ ______ 18.What is the purpose of Cr1 [D1] ? _________________ ______________ 19.When aligning the super heterodyne receiver, Which section is aligned first ? ______________ ___ _______ 20.What method of troubleshooting is used on the super heterodyne receiver ? _________ __________; _______ ________ ___________. 21.There are four frequencies produced by heterodyning. What frequency is used by the super heterodyne receiver ? ___________________

27. CF351 F07 - 27 PE Set UPPE Write UP SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER Lesson Test Lesson Test; Lesson Test: Standard: 10 Questions W/in 20 Minutes. 70% Minimum Accuracy. Reference:NONE RF TUNER CONVERTER OR MIXER IF AMPLIFIER DETECTOR AF AMPLIFIER SPEAKER LOCAL OSCILLATOR

28. CF351 F07 - 28 PE Write UP SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER PE Write Up Example 1. PE Write Up; Example 1. CardTPIndicationTest Equip 39TP 15F-Gen 39TP 9F-Gen 38TP 2F-Gen 38TP 311.89 VDCDMM 38TP 2280mVDC DMM 38TP 4280mVDCDMM 38TP 2/40/0  DMM 38 Card: 38 LO Circuit: LO Q1 Component: Q1 Short Malfunction: Short

29. CF351 F07 - 29 PE Set UP SUPERHETERODYNE RECEIVER TIII: SUPERHETERODYNE RECEIVER PE Write Up Example 2. PE Write Up; Example 2. CardTPIndicationTest Equip 39TP 15F-Gen 39TP 9F-Gen 39TP 12F-Gen 39TP 1012 VDCDMM 39TP 9780mVDC DMM 39TP 11220mVDCDMM 39TP 10/9Hi/Hi  DMM 39 Card: 39 1 st IF AMP Circuit:1 st IF AMP Q2 Component: Q2 Open Malfunction: Open