SynthVFO

Assembled by PE0CWK


Based on the synthesized VFO kit of PA0KLT
with Firmware V4.19
More info at   www.SDR-kits.net
PA0KLT Synthesized VFO. Pcb Second Issue with Coilcraft WBC4-1 transformer fitted. See PA0KLT LCD Synthesizer kit Manual issue V5.4 (www.SDR-kits.net) PA0KLT Synthesized VFO PA0KLT Synthesized VFO mounted on VERO board together with ic CD4050 (not yet fitted) for buffered outputs to drive a  digital band selector Backside VERO board with PA0KLT Synthesized VFO together with ic CD4050 for buffered outputs to drive a  digital band selector
Backside of the assembled frontpanel with the display section board. Backside of the assembled frontpanel together with the display section board. Power supply 2x 9V Ac, 0.5 Amp.  Unregulated Vin1 (+12.6V / 120mA) connected to the PA0KLT synth.VFO board assembly, display section and frontpanel indicators. Unregulated Vin2 is connected to an adjustable (+1.5 ... +11.5V) low drop voltage regulator. An output of +9V/0.5A is garanteed. For future use. Backside powersupply board
Inside view of the assembled synth. VFO Inside view of the assembled synth. VFO Backpanel of the synthesized VFO. Buffered bandselect outputs at pins 1 to 4 of sub-D connector correspond with pins 1 to 4 of P4 resp. on the synth. VFO baord (A to D resp.).  Pin 5 of the sub-D is connected to ground. Pins 6 to 8 of the sub-D correspond to pins 9, 14, and 15 of P4 on the synth. VFO board for selecting  the Mode offset.   Pin 9 of the sub-D corresponds to pin 16 of P4. Connecting this pin to ground  (separate switch on the backpanel) removes the IF-offset. Synthesized VFO. The RF output power can be switched off with the RF switch on the frontpanel. It connects pin 2 (OE) of the Si570 chip to ground.  The highest frequency is determined by the Si570 type used.
RF-out at 7 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 7MHz after an external  50 Ohm 7 MHz 5 pole Low Pass filter. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 10 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 20 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load.
RF-out at 50 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 100 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 150 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 200 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load.
RF-out at 250 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 300 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. RF-out at 350 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. Not sure what the scope exactly is affecting the displayed information around this frequency. RF-out at 400 MHz. All measurements with 400 MHz bandwidth scope and 50 Ohm load. Not sure what the scope exactly is affecting the displayed information around this frequency.