When working on the design УSW radio station, I faced the task of building a simple synthesizer frequency 144 - 146 MHz.
Looking through different designs synths I came across a synthesizer Michael Kislinsky (RX9CBI). This design I really liked its simplicity and the lack of scarce components. However, I was not satisfied with the control switches. So I decided to change the schema, enter the number of additional features. In the process of finalizing a schematic diagram changed only cosmetically, the basis of it is still a scheme RX9CBI, and the program had to be rewritten completely.
So, what made new:
As in the original design left the mode spacing frequency 600 kHz repeater.
(click to enlarge)
Short explanations to the scheme.
J3 - contact connection of the button to increase the frequency on 25 kHz (+25)
J4 - contact connection button to reduce the frequency 25 kHz (-25)
J6 - contact connection of the button to increase the frequency on 100 kHz (+100)
J7 - contact connection button to reduce the frequency 100 kHz (-100)
the second button contacts connected to the "common" wire of the synthesizer.
Simultaneous pressing of buttons +25 and -25 switches the synthesizer in repeater mode. In extreme the left discharge indicator displays the letter "R". Clicking these two buttons returns the synthesizer from repeater mode to normal mode and the letter "P" in the left digit of the indicator disappears.
Simultaneous pressing of buttons +100 and -100 switches the shift step. After that the buttons J3 and J4 rebuild the synth at +5 and -5 kHz, respectively, and the buttons J6 and J7 on +20 and 20 kHz. Pressing again returns the synthesizer in the adjustment mode 25/100 kHz.
To enable: relay is switched off, frequency 145300 (in Tambov shared channel), tuning step 25/100 kHz.
Contacts J9, J10, J11 - connecting the LCD from the phone "Panaphone."
Contacts J12, J13 control pressing the buttons. Connects to the piezo Squeaker from Chinese phones.
Contact J14 - switching the reception - the transfer. Transfer - log. "0".
Contact J15 - microphone input.
Contacts J1, J2 - power to the synthesizer.
Contact J5 - output "capture". Can be used to lock the transmitter in the absence of the capture loop.
Contact J8 is the output of the synthesizer.
The synthesizer is implemented on a single-sided PCB with jumpers. This is done due to the fact that in Amateur conditions is difficult will produce a double-sided Board with plated holes. Easier to unsolder a few jumpers.
The program for the independent production the synth can take here.
I Express my gratitude to M. Kislinsky (RX9CBI) for help in working on this design.
Author: A. Denisov, Tambov; Publication: N. Bolshakov, rf.atnn.ru