950 - 1300 MHz, 1Watt Transmitter
( based on comtech DFM1200TM1W )
Original Comtech design.
Audio / Video transmitter, +30dBm output.
Uses U6239B pll chip, controlled by a MDT2005 o.t.p. microprocessor.
4 fixed frequency's, 1020, 1050, 1080 & 1210 MHz. Set with a slide switch.
-------------------------------------------------------------
Modifications.
decided to write PIC16F84 code because
-real frequency range is somewhere between 950 - 1300+ MHz
-build in microprocessor, can't be programmed again (= o.t.p.).....
-build in pll chip uses I2C ( or 3-wire SPI ) for serial control.
STEP 1 - Deactivate build in microprocessor, by disconnecting 2 pins from pcb.
STEP 2 - Connect 2 wires to build in pll, to provide external I2C control.
STEP 3 - Use PIC16F84 with lcd readout to control the build in pll.
STEP 4 - Connect pll chip to 16F84 ( note !!, don't use 5Volt from Tx to power 16F84 )
-------------------------------------------------------------
STEP 1
|
STEP 2
|
STEP 3
|
STEP 4
|
Comtech DFM1200
|
-- Click on hex code for downloading --
Comtech site
13cm RECEIVER ( 2300 - 2550 MHz).
based on Comtech 13cm tuner unit ( = DFM2400RTIM8-00 ) with SP5055 PLL
I.F. frequency = 479.5 MHz, I.F. bandwith = 18 MHz
- click for hexcode - 2300 => 2550 MHz
- click for hexcode - 2200 => 2700 MHz
PIC16F84 & LCD
|
LCD CLOSE UP
|
Sattelite Tuner ( 900 - 2150 MHz ).
For sattelite tuners with a I2C sp5055 pll chip.
Uses same hardware as the 13cm Rx above.
frequency on display = 900 -> 2150 MHz, 1 MHz steps.
pll frequency = 900 -> 2150 MHz + 479.5 MHz.
PIC16F628 version.
-- click for hexcode ---
