A Panadapter Solution for the K2

I loved building my K2 many years ago and still really enjoy operating this fine rig. For a more than 20-year-old design, the receiver is still top notch and it is still a pleasure to operate. Although, it does not contain many of the bells and whistles found in the more modern designs especially in the SDR arena. One of the functions of today’s SDR based rigs I miss with my K2 is a panadapter.

This page describes my setup using my K2 with the DXE IF Buffer Amp installed, feeding the IF to a SDRPlay RSP2. The output of the RSP2 is then fed to a very good SDR program called HDSDR. HDSDR is freeware and is able to use Omni-Rig for rig control. This will give you point and click tuning operation in HDSDR and tune the K2 to the frequency you selected.

HDSDR on 40m
HDSDR displaying the entire 40m band fed from the IF of my K2

Specifically, I set out to setup the K2 with a panadapter in the classic sense with very tight integration. i.e., having the HDSDR interface control the K2 and vice versa and still have the ability to use the K2 for audio output, crystal filtering etc. There is also a way to simply use the K2 as an IF front end and use HDSDR with its fully capable DSP and audio functions for all filtering and audio etc. This is an excellent way to configure HDSDR as a second receiver for the K2. Tuning of HDSDR is independent of the K2 in this configuration and would allow monitoring a signal separate from the TX frequency on the K2 VFO. This allows split operation without placing the K2 in split mode.

the basic connection setup between all the components

Basic Connection Config

The setup in detail

Here is a detailed PDF that describes the installation of the DXE IF Buffer Amp board in the K2: DXE IF Buffer Amp Install
And here is a detailed PDF that describes the software setup for using the IF output of the K2: K2 DXE IF Buffer Amp Panadapter Setup

I also developed a spreadsheet to calculate the HDSDR offsets based on the BFO frequencies set during CAL FIL as described in the K2 DXE IF Buffer Amp Panadapter Setup document. These offsets will precisely sync the HDSDR frequency spectrum and the K2 VFO: HDSDR K2 Offset Calculator