TDA1046 DOUBLE CONVERSION RECEIVER

UN  MIC RECEPTOR CU FOATE  BUNE PERFOMANTE  CONSTRUIT PE 14MHZ . ARE UN FILTRU  TRECE BANDA  SI UN  MIC  AMPLIFICATOR  CASCOD CU  TRANZISTORI  BF256A .URMEAZA  UN MIXER IN INEL  CU PATRU DIODE  DE TIP EFD  CU GERMANIU , DAR MERGE SI CU DIODE  CU SILICIU. LA INTRARE  IN MIXER  ESTE UN COND DE ACORD PE  14MHZ NUMEROTAT CX1. AICI CU UN   COND .VARIABIL CONECTAT SE VA FACE ACORDUL  PE MAXIM  DE SEMNAL. DUPA  GASIREA  VALORII  SE VA  CONECTA  UNUL FIX. TOT ASA SE VA  PROCEDA  SI PENTRU  CX2 .  CX1  FIIND PENTRU BANDA  DE 14MHZ ,  IAR CX2 PENTRU  PRIMA MEDIE FRECVENTA.  COND CX3 ESTE  PENTRU CEA  DEA  DOUA  MEDIE  FRECVENTA SI  ACESTA ARE VALOAREA  INTRE 820PF  SI 1000PF .DEPINDE  DE  CE VALOARE  ARE  FRECVENTA  ,455KHZ  SAU  500KHZ. FRECVENTA QUARTULUI  ESTE INTRE  8MHZ  SI 10MHZ. DE VALOAREA  LUI  DEPIND FRECVENTELE   INTERMEDIARE  SI FRECVENTA  OSCILATORULUI  VARIABIL !!.  UN  EXEMPLU . DACA  AVEM QUART  DE  10MHZ  , ATUNCI  VFO  VA AVEA 4.5 LA  4.850MHZ. PRIMA  MEDIE  FRECVENTA  VA  FI  PE  9,5 ,  IAR  CEA  DEA  DOUA  PE  500KHZ . LA  PINUL 3  SE  INJECTEAZA  SEMNAL  DE BFO .MULT  SUCCES  SI  MULTE  73  DE YO6QCM 

A  SMALL  RECEIVER WITH VERY  GOOD  PERFORMANCE. Is BUILT for 14MHZ. A BAND PASS FILTER And A SMALL AMPLIFIER With TRANSISTORS BF256A CASCOD.A MIXER IN THE FOUR-RING-TYPE DIODES EFD WITH GERMANIUM, BUT IS OK WITH SILICON DIODES. ENTRANCE into the MIXER is a COND AGREE on CX1 NUMBERED 14MHZ. HERE WITH A COND.VARIOUS CONNECTED WILL MAKE AGREEMENT ON THE MAXIMUM SIGNAL. AFTER FINDING THE VALUE WILL CONNECT ONE FIX. SO, TOO, WILL PROCEED To CX2.  CX1 is for the 14MHZ, and the AVERAGE FREQUENCY for CX2.  CX3 is for  the SECOND FREQUENCY and the AVERAGE VALUE BETWEEN 820PF and 1000PF.DEPENDS on what VALUE HAS the FREQUENCY of 455 kHz, or 500KHZ. COMMON QUART is BETWEEN 8MHZ and 10 MHz. FREQUENCIES DEPEND on the VALUE of INTERMEDIATE FREQUENCY VARIABLE OSCILLATOR!.  AN EXAMPLE. IF WE HAVE 10 MHz, then QUART VFO WILL HAVE 4.5 to 4.850 MHZ. The FIRST FREQUENCY WILL BE on AVERAGE 9.5, and the SECOND on 500KHZ. To PIN 3 SIGNAL is INJECTED BFO.      GOOD LUCK and 73 YO6QCM