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VHF - FM - Repeater - Project    DB0HGW

repeater control

The repeater is controlled by a simple microcontroller 87C51 with 8kB

eprom internal. That's why the circuit arragment is quite simple. It is

built on universal drilled board. The whole control module is housed by

a tin plate box (100mm x 160mm x 30).

In hardware version 1.0 the following functions (together with the software)

are implemented:

PTT control, generating audio tone with call, squelch and 1750 Hc detection (digital),

APRS channel monitoring (especially for APRS interlocking in case of radio signal)

Hardware Version 1.0 circuit diagram:

audio control and speech proccessing

This circuit was developed and published by Matthias Fehr, DL4MF, in

CQDL 12/2000 page. 892 or  use the CQDL-download area  clipper.zip  .

 

view in the control module of the repeater

 

PREAMP/CRYSTAL FILTER

DUPLEXER

REPEATER DOCUMENTATION C-SOURCES updated:01/11/02 in german only !

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