K3 series IF Buffer – PA K3The K3 and successors are recognised as the rig of choice by the vast majority of serious contest operators and DX’ers worldwide. When combined with the P3 Panoramic Adaptor, SDR capabilities can be realised on the small P3 screen or on a larger display using the SVGA option.  However, if you want to use the IF output to drive any other SDR equipment, there are some issues that need addressing –

• the output level of the IF port is about 15 to 20dB lower than it should be, and
• there are strong Local Oscillator signals from the K3 presented at the IF Out port – this is still the case if you run from the P3 IF Out port.

The PA K3 is a small external buffer unit that can be attached to the IF out port of any of the series (K3, K3S and P3).   It provides a filter centred on 8.215MHz and an amplifier with approx 20dB of gain, bringing signal back up to the correct levels. The filter uses wound toriodal inductors, rather than lower Q SMD inductors.

Connections to the PA K3 are via BNC cables (not provided) and it requires a source of +13.8V DC at about 10mA. This may be taken from the K3 or an external source.  The PA K3 is available as an assembly kit – the PCB is completed and aligned, leaving you to complete the mechanical assembly.

PA K3 Technical Manual

Completed unit view	Internal view of PA K3	PA K3 kit contents

SDR’s?

There are many on the market, and most are compatible with more that one software package.  Based on availability, economics and performance, hupRF recommends the SDRplay range as suitable SDR’s for use as an external K3 display using the PA K3 .  Click on the link below to go to theSDRplay website – SDRuno software is also downloadable from the site.