From: mckillnm@unix2.tcd.ie (Marky Mark)
Newsgroups: sci.electronics
Subject: FM Transmitters (3000m range)
Summary: circuit digms
Date: 25 Oct 91 13:46:45 GMT
Organization: Trinity College, Dublin


                              Transmetter Plans
                              -----------------


  Gnd                                    + 9-12 V
   +                                         +
   |                                         |
   +---------- Mic --+----- R1 --------------+
   |                 |                       |
   |                C 1                      |             | (b)
   |                 |                       |        (e) --- (c)
   |         +-------+                       |        ----v \-----
   |         |      R2                       |          
   |     T1  |       |                       |         Transistor
   |        ---      |                       |
   +--------v \------+---- R3 ----+---- R4 --+
   |                              |          |
   |                    +---------+---- C2 --+
   |               T2   |                    |
   |                   ---                   |
   +------- R5 ------+-v \--------+---- L1 --+
   |                 |            |          |
   |                 +------ C3 --+---- C4 --+
   |                              |          |
   +------- L2 ------+------ C5 --+          |     ASCII art at the BEST !!!
   |                 |                       |
   |                 |           +---- TC1 --+
   |            T3   |           |           |
   |                ---          |           |
   +----------------v \----------+----- L3 --+
   |                             |           |
   |                             |           |
   |                  Ant -- C6 -+           |
   |                                         |
   +------------------ C7 -------------------+

   List of parts :-

  Resistors :-

       R1,R4      12K
       R3         1K2         All 0.125 W except R2 (0.25W)
       R5         330R         
       R2         2M2 


  Caps :- (all plate ceramic)

       C1,C2      4n7
       C3         2p2
       C4         10p           TC1  2-22pF
       C5         8p2
       C6         47p
       C7         10n

   IC's :-

       T1         BC184C      
       T2         ZTX300
       T3         2N3866

   Coils :-

       L1         Toko RF coil Green
       L2         4u7 H Choke
       L3         Toko RF coil Green (no core)

Notes :-

       1)  Rember ...... Using a transmitter could be illegal, check your
           conrties laws. (I am not responsible for anything U do !!!)

       2)  Use about 300mm of hookup wire for an antenna.  Try hooking the
           antenna up to the telephone (black) wire for about 100m of wire.

       3)  PSU :- Use a simple 9V battery although 12V can be used.

       4)  Tune the transmitter :-
               Simply turn the dust core in L1.  This is best done using 
               a match.  DON'T use a screw driver, you will not only mess
               up the tuning BUT U may break the core !!


NB :- Linking anything to the phone line is illegal (do so at your own risk !).

Disclamer :-

 I Have nothing to do with anything U do ..... 


                             Enjoy ....


                            Mark

                            (mckillnm@unix2.tcd.ie)
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