A simple FM modulated amateur radio television transmitter for the 23 cm (1.24 - 1.3 GHz) band.

Using a 4 MHz crystal, divide-by-128 RF prescaler and a reference frequency of 7812.5 Hz, the MC145151 PLL is easily programmed in 1 MHz steps.  The resulting N value is equal to the transmitter frequency, in MHz.

Example transmit frequency of 1.25 GHz (1250 MHz):

High N-divide pins: 1024, 128, 64, 32, 2.  All others are low (grounded).

On the receive side, use a standard C-band satellite tuner, minus the blockconverter.  Tune the satellite tuner to channel 10 to receive a signal at 1.25 GHz.

C-Band Satellite Receiver IF Frequencies

Channel		Satellite Downlink Frequency (MHz)		Tuner Receive Frequency (MHz)

1		3720						1430
2		3740						1410
3		3760						1390
4		3780						1370
5		3800						1350
6		3820						1330
7		3840						1310
8		3860						1290
9		3880						1270
10		3900						1250
11		3920						1230
12		3940						1210
13		3960						1190
14		3980						1170
15		4000						1150
16		4020						1130
17		4040						1110
18		4060						1090
19		4080						1070
20		4100						1050
21		4120						1030
22		4140						1010
23		4160						 990
24		4180						 970

Schematics

• GBPPR 23 cm (1.2 GHz) Amateur Radio Television Transmitter  (111k PNG)
• GBPPR 23 cm (1.2 GHz) 1.5 Watt ATV Amplifier  (25k PNG)

Pictures

• 1.2 GHz ATV Transmitter  (119k JPEG)
• C-band Satellite Receiver LNA Modified for use on 1.2 GHz - Picture 1  (67k JPEG)  Original case above for comparison
• C-band Satellite Receiver LNA Modified for use on 1.2 GHz - Picture 2  (99k JPEG)  Modification includes removing the 3.7 GHz isolator, adding a N-connector and coax for RF input, removing and bypassing the 3.7 GHz stripline bandpass filter and adding a 82 nH inductor on the bias tee.
• 1.2 GHz M67715-based 1.5 Watt Amplifier - Picture 1  (40k JPEG)  Outside case overview
• 1.2 GHz M67715-based 1.5 Watt Amplifier - Picture 2  (118k JPEG)  Internal overview
• 1.2 GHz M67715-based 1.5 Watt Amplifier - Picture 3  (71k JPEG)  Internal close up

Links

• 2.3GHz ATV TX by Ian G6TVJ
• Alternative 1.2 GHz ATV Transmitter  (52k GIF)
• Alternative 2.4 GHz ATV Transmitter  (52k GIF)
• Another 1.2 GHz ATV Transmitter  (284k PDF)

Datasheets

• Z-Comm CLV1137 VCO  (46k PDF)
• Fujitsu MB506 Prescaler  (65k PDF)
• Elantec EL2020 50 MHz Current Feedback Amplifier  (419k PDF)
• Mitsubishi M67715 RF Power Module, 1240-1300 MHz 1.2 W  (152k PDF)