1. Inside the K3 High Performance Rig Design
Dynamic Range is your friend!
Eric Swartz - WA6HHQ
PNW VHF Conference 2008
Hands on Ham Radio.

2. The K3 HF Transceiver

3. K3 – What’s New? Switching Mixer = Better Dynamic Range
Low Noise Synthesizer
High performance 1st IF Filters ->200 MHz
IF Shift / Pass Band Tuning
High Performance Noise Blankers: H/W and DSP– Both Adjustable
8 Band Parametric TX & RX Equalizer
PSK, RTTY, CW Decode. (Send data modes from CW paddle!)
General Coverage RX BPF Option
High Performance ATU w/2 ANTs - Matches 10:1 SWR
100% Remote Controllable; Built-in isolated sound card interface
K3 MCU & DSP Software Upgrades via the Internet (or local files)
Up to 9 Transverter Bands with correct frequency display.

4. KRX3: High Performance Sub-Receiver
Fully independent High-Perf RX
Independent Synthesizer, NB, filters etc
Split off of main RX path or 2nd Antenna
3 modes of operation:
Sub RX = VFO B (and VFO B=TX if running split)
Linked: Sub, VFO B, Tracks VFO A (with or without offset)
Diversity: Sub = Main, VFO A, Incl Filters. VFO B = TX split

5. K3 PC Based Panadapter PowerSDR Public Domain Software on PC
Real-Time Spectrum Display
Use the K3’s IF output via LP-Pan ( Requires KXV3)
Full Integration with K3 – Panadapter Tracks Main/Sub VFOs, Point and Click Tuning etc.
( Run Video Clip )

6. PR6 Preamp

7. PR6 Preamp PHEMT (GaAs FET) NF = 0.5 dB typ. (0.7 spec.) 18 dB gain
PR6 & K3 MDS = -143 dBM
DR3 = 100dB+ (PR6 & K3)
Direct connection to K3 RX out/in
K3 controlled PR6 bypass mode
$ intro price

8. K3 Design Parameters Low Synthesizer 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
The K3’s Phase noise (-139 dBc at 10 kHz) is dB lower than the K2’s, which was already considered one of the best.

9. K3 Design Parameters Receiver Gain Distribution
Sensitivity vs Dynamic Range
Maximize Dynamic Range at your needed sensitivity.
No more sensitivity than needed for band noise.
Too much front end gain limits dynamic range!

10. IMD Dynamic Range “Intermod”
Inter-modulation between strong multiple off frequency signals produces distortion products inside the receive IF bandwidth.
Dynamic Range = IMD Sig Level - MDS
K3 IMDDR3: dB at 5 kHz

11. Blocking Dynamic Range “De-sense”
De-sensing of RX by off freq. signals
Impacted by RX front end design.
Impacted by PLL Phase Noise
Test Methods: 20, 5, 2 kHz spacing

12. Crystal Filters Become the Limiting Factor
Crystal Filters are Electro-Mechanical Devices
As signal level increases, minor defects cause distortion.
Once the front end D.R. is improved, the xtal filters become the limiting factor.
We found industry standard xtal filters could not handle our large signal levels.
We worked with our suppliers (Inrad and others) to supply higher performance filters.

14. Subject: K3 testing
Date: Sat, 09 Feb 2008
From: Rob Sherwood
Dear Eric and Wayne,
The high side and low side IMD is very well behaved, and virtually identical. Good job.
3rd order intermod dynamic spacings:
100 kHz 500/500 filtering: 104 dB
20 kHz 500/500 filtering: 104 dB
5 kHz, 500/500 filtering: 102 dB
2 kHz 200/200 filtering: 101 dB
It looks like you are top dog now! Better than the Orion II, the Flex 5000A and certainly better than the IC-7800.

15. AGC Performance The K3 has 2 optimized AGC Circuits
DSP AGC handles signals up through S9+30
H/W AGC (after xtal filters) protects the DSP for stronger signals.
DSP AGC optimized pulse rejection = Smooth RX
Subject: K3
Date: Sat, 09 Feb 2008
From: Rob Sherwood
By the way, the K3 passes the ‘Sherwood AGC test’ with flying colors.
1 V. P-P very fast rise time pulse, 1 PPS, is basically ignored by the AGC if the AGC set to the default "pulse ignore" setting.
I think it is better than all the other rigs that have come out in the last few years which fail miserably: FTDX-9000, FT-2000, Orion II, Omni-VII, IC-7000, IC-7800.

16. K3: The Basics = Great RX Performance
Down-Conversion: Simpler -is- better
Strong Front End Design
Hi-Performance Switching Mixer, Post Mixer Amp.
Narrow Bandpass Front End Filters
Low Phase Noise
Optimal Gain Distribution; AGC Design
High Performance Crystal Filters