High Performance IF and Transverter Design Or how I learned to love Dynamic Range… Eric Swartz WA6HHQ Hands on Ham Radio.

The K2/100 CW/SSB HF Transceiver

XV Transverters for 50, 144 and 222 MHz

High Performance K2 Transceiver Sensitive: -136 to -138 dBM MDS Wide Dynamic Range: +21 dBM IP3 Quiet IF XV Transverters Sensitive: 0.8 dB NF Wide Dynamic Range: +20 dBM IP3 Built in TX Keying Sequencing (20, 50, 200 mS) Work with the K2 and most HF Rigs

XV 144 NF Plot (143 – 147 MHz)

IF Rig Design Parameters Single Versus Multi Conversion Are more conversions better? Why go to double or triple conversion? General Coverage RX Cascadable filters

Multi versus Single Conversion Multi Conversion More IF stages + Wide first roofing filter = Easier Overload, More Noise Multiple IF Filters Single conversion Fewer Stages = less noise and distortion Immediate conversion to 1st IF narrow filter Better close in dynamic range DSP cascaded after crystal filters

Design Parameters Phase Noise Phase noise measures the off frequency sideband energy of your local oscillator. Excessive phase noise: Limits Sensitivity and Dynamic Range by mixing off frequency signals on to your IF frequency Transmits broadband noise Crystal Osc. vs Linear VFO vs PLL vs DDS

PC-1600a Phase Noise

K2 Phase Noise

Design Parameters Receiver Gain Distribution Sensitivity vs Dynamic Range Maximize Dynamic Range at your needed sensitivity. Balance Transverter NF and Gain with IF rig’s Too much front end gain limits dynamic range!

IMD Dynamic Range Inter-modulation between multiple off frequency signals producing interfering distortion products inside the receive IF bandwidth. Test Methods: 20 kHz, 5 kHz spacing Swept IMD Test

Dynamic Range vs MDS

Blocking Dynamic Range De-sensing of RX by off freq. signals Impacted by RX front end design. Impacted by PLL Phase Noise Test Methods: 20 kHz, 5 kHz spacing Swept Blocking D.R. Test

IC-706 Swept Blocking Dynamic Range

K2 Swept Blocking Dynamic Range

System Design Parameters A great XV can’t fix a poor IF rig! XV and IF both need wide dynamic range IF rig needs good close in performance Use only as much XV gain as needed Too much front end gain KILLS dynamic range A better IF rig NF needs less XV gain Balance NF and system gain with dynamic range

In-Band Audio IMD Audio Distortion from multiple RX signals inside narrow IF filters. Receiver ‘Mush Factor’ in pile-ups Impacted by: AGC (Fast, Slow, Too much, Where applied in the RX chain) RX Filter Shape and group delay Product detector artifacts Audio amplifier distortion

Mark V FT1000MP In-Band Audio IMD

K2 In-Band Audio IMD

K2: Basics = Great RX Performance Focus on the Basics Single Conversion: Simpler -is- better Strong Front End Narrow Bandpass Front End Filters Strong Mixer, Post Mixer Amp. Clean PLL VCO (Band Switched) Optimal Gain Distribution; AGC Level IF AGC + DSP after the Xtal Filter Clean Audio Chain

XV Series Transverters Stackable on the same IF bus +17 dBM Mixer for dynamic range PHEMT front end; <= .8 db NF 50, 144 and 222 MHz - Stackable Use with K2 and Most Other Rigs Built in TX Sequencing up to 200 mS

K2 Block Diagram