The PA0KLT Low Noise VFO Synthesized Kit

Standalone VFO design

Built in LCD and Controller

No Computer required

Kits available with various frequency ranges

Optical Encoder available as optional extra

• Output is a squarewave - minimum frequency is 3.450 MHz
  

• Low noise Synthesizer chip controlled by an Atmel Mega 88 or Atmel Mega168 with PA0KLT Firmware

• Controller with connections to an external 16 or 20 character x 2 lines LCD Display (16x2 LCD supplied in kit)

• Firmware written in Assembler for optimum speed and control

• Logical Outputs for selecting 1 of up to 16 external Filters for Amateur Radio Bands from 136 kHz - 440 MHz
  

• A 96 step mechanical rotary encoder for tuning is supplied in the kit (Optional 128 or 256 step Optical Encoders supported)

  Optional Functions:

  Optional RIT (Receive Incremental Tuning)
  RIT is enabled by pressing the RIT, a second press on the RIT button disables the RIT offset. RIT is also disabled in TX/Lock Mode. A press on the 2nd button resets any RIT offset back to 0 kHz. The maximum RIT offset range is +/- 10 kHz/

  
  

Fast Tune is enabled via a suitable Encoder fitted with switch or by a separate push button switch (Optional hardware required). When the switch is briefly pressed, this provides for a 25x Fast Tune rate, whilst a second press revert to the Normal Tuning as before. For example, with a 24 step encoder, enhanced by the firmware to 96 steps/turn and a 10 Hz tuning step selected this results in a resolution of 0.96 kHz per turn. When Fast Tune switch is enabled the resolution increased to 24 kHz per turn until Fast Tune is switched off again.

             PA0KLT V4.20 Connection Diagram for RIT & Fast Tune Options

             To implement Fast Tune, a 32 step Optical Encoder is available to order as an optional extra.

The PA0KLT Low noise VFO kit is available with various Si570 Chips which set the maximum frequency range required up to 1417 MHz (1.417 GHz)

• Kit A supplied with Si570CAC - covers 3.45 - 210 MHz - output is CMOS Square wave
• Kit B supplied with Si570BBC - covers 3.45 - 280 MHz - output is LVDS Square wave
• Kit C supplied with Si570BBB - covers 3.45 - 945 MHz - output is LVDS Square wave
• Kit D supplied without chip
• Kit E supplied with Si570DBA - covers 3.45 - 1417 MHz - output is CML Square wave
• Kit F supplied with Si571CFC - covers up to 210 MHz – output is CMOS square wave output (provision for AF input for FM Modulation

   A quality double-sided PCB

    Programmed Atmel ATMEGA168

    6 pushbuttons

    Mechanical rotary encoder without switch

    All connectors

    LCD display with backlight

    Si570 chip supplied as ordered