Thursday, 1 October 2015

Concept Session 5 - VFO Build

This session covers the build of the actual VFO PCB shield. The shield carries both the VFO module, a SN74AC74 IQ generator and the RTC module.

Concept S5 VFO kit 003



The build needs a number of tools including a good small-point soldering iron of reasonable wattage (>40W suggested), cutters, tweezers and a lens for SMD mounting.

Concept S5 VFO kit 004

The first thing to do is to mount the SMD device, the SN74AC74. This mounts with the ident at the bottom.

Concept S5 VFO kit 013

Concept S5 VFO kit 014

Next mount the passive components (just three parts).

Concept S5 VFO kit 015

The the two modules Si5351 and RTC.

Concept S5 VFO kit 016

Lastly the headers with connections to the Arduino (2 x 8 & 2 x 6 pin), the RFbus (8 pin) , the Rotary Encoder (5 pin) and the LCD (4 pin).

Concept S5 VFO kit 017

At this point you are ready to test your VFO. Plug it into your Arduino, power it up and load the sketch My_VFO_40M. This will give you a VFO for the 40m band. It will display the frequency and the Band Plan. Pushing the encoder shaft/button will change the tuning steps from 100Hz to 1kHZ to 10kHz and back again.

Final board

VFO Complete

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