1. Which HF Transceiver is Best for Me?
Brian Machesney, K1LI

2. What's the Best HF Transceiver for Me?
Tips on
Radio Selection Strategy
Brian Machesney K1LI

3. Goal of this Presentation
Arm you with a strategy to choose a radio that’s appropriate to your individual situation
A number of radios will be used to illustrate various criteria, but any radio can be evaluated in the same way
NOT to promote or disparage any radio or brand vs. any other…
but my own definition of value will inevitably creep in
I invite you to comment on your own definitions of value!

4. Reference Sources Most of this material came from somewhere else…
Sherwood Engineering: RMDR, IMDR measurements
ARRL
Product reviews: lab-grade testing, plus color commentary
“Test Procedures Manual”: measurement methods
VA7OJ, I2VGO, Linearizer Technology Inc.: noise power ratio
Clifton Laboratories: AGC measurements
Audio Systems Group: compiled transmitter spectra from ARRL Lab
Company and distributor materials
eHam classifieds: used equipment prices

5. Situations New ham – bewildering amount and variety of information
Capability upgrade – more effective communications
Use modes
Casual vs. competitive
Home vs. road
Standalone vs. transverter
Dominated by CW / SSB / Digital
Your predilection here!

6. How did you choose your last radio
How did you choose your last radio? … and how do you feel about that decision today?
Opinions of personal or on-air acquaintances
On-air observations
Online, magazine reviews
Company web sites, hamfest exhibits, reflectors
Online chat room, special interest group web site
Technical blogs
Previous experience with a brand or model
e.g., at your local / favorite multi-multi contest operation!

7. Radio Selection Criteria
Price and “features” – one piece of an entire station
Receiver – you can’t work ‘em if you can’t hear ‘em
Transmitter – you mean, this matters?
Interface – logging programs, digital modes
Ergonomics – initial setup, on-the-air operation
“Intangibles”

8. Price and Features A Balancing Act
New vs. “pre-owned”
Recent models may have significant hardware revisions
Band coverage, transverter interface
Output power, ATU
Display
“Character” vs. “Graphical”
Bandscope, touchscreen menu buttons
Interface convenience
Upgrade path: filters, functions, features
Power supply: internal vs. external
Size, weight

9. Receiver-Specific Criteria
Ability to hear desired signals
Sensitivity
No longer an issue at HF vs. atmospheric noise
May be important if you want to use with transverter
Selectivity
Hardware – L-C, ceramic, crystal, mechanical filters
Software – DSP – bandpass, notch, noise reduction
Distortion – audible “junk” created in the receiver
Listening fatigue – how it “sounds”
Audio distortion
Response to impulse noise

10. Contesting: a Dynamic Environment
“Running” produces higher scores than “S&P”
“Loud” stations do more running
“Not loud” stations do more S&P
If you’re running, “not loud” stations will be calling you …
… while you are surrounded by other “loud” stations
When you S&P, you may be calling “not loud” stations…
… while they are surrounded by “loud” stations
CQ WW 2014 log submissions
Power CW
SSB
High
3011 (41%)
3240 (41%)
Low
3821 (52%)
4337 (55%)
QRP
505 (7%)
344 (4%)

11. Simplified Receiver Block Diagram What Could Possibly Go Wrong?!
Local Oscillator
IF Amp, Detector
Audio Amp
Preselector
IF Filter
Antenna
Speaker
Active stages are not perfectly linear
Active and passive stages can overload
Mixing is multiplication: inherently nonlinear!
Mixers mix everything at their inputs
RF Input
Local Oscillator
Image
Desired IF Output
Amplitude
Frequency
IF Filter Passband

12. Mixers Mix Everything at Their Inputs Phase noise, distortions “smear” spectra
Real world oscillators produce noise sidebands
Amplifier nonlinearities, ALC, CW rise/fall times spread the spectra of input signals
Multiple signals appear at the mixer’s RF input
Result: noisy jumble in the IF LO
Amplitude
Desired IF Output
Image RF
Frequency

13. Reciprocal Mixing (RM)
“…noise generated [by] the mixing of the First Local Oscillator’s Phase Noise and a strong adjacent, steady signal.”
“Clean” RF source
Measurement Setup
Step Atten
Receiver
14.027
14.025MHz
ANT
Audio Distortion Meter
Low-noise XTAL Osc
SPKR LO
Amplitude
Desired IF Output
Image RF
Frequency

14. Price* (USD) RMDR (dB) = SRF (dBm) - MDS (dBm) Notes:
Flex6700
TS990
Notes:
* RED = retail, BLACK = used
IC7700
TS990
FTDX5000
Flex6300
IC7700
Price* (USD)
IC9100
IC7600
K3?
Flex5000
KX3
FTDX3000
TS590 K3
Eagle
Flex3000
756P2(IR)
TS590

15. Intermodulation Distortion (IMD)
“…range of signals that can be tolerated by the [receiver] while producing essentially no undesired spurious responses.”
Hybrid Combiner
Receiver
ANT
Audio Distortion Meter
RF Gen 2
14.000
SPKR
2-kHz Measurement Setup
Signal Analyzer
RF Gen
Step Atten
RF Gen 1
13.998 LO
Amplitude
Desired IF Out
1 2 IMD RF
1 2
Image
IMD 2 1
Frequency

16. Price** (USD) IM3DR (dB) = SRF (dBm) - MDS (dBm) Flex6700 TS990
IC7700*
TS990
IC7800*
FTDX5000*
Flex6300
IC7700*
Price** (USD) K3
IC7600*
IC9100
OrionII
OmniVII
FT2000
Flex5000
756P2(IR)
FTDX3000*
K2*
TS590*
KX3
FT1KMPV(IR)
Orion
K3*
FT1KMP(IR)
ArgVI*
Flex3000*
IC7000
FT1000D
756P2
OmniVI+
Eagle*
TS590*
IC756P
TS830S/YK88

17. Noise Power Ratio (NPR)
“… white noise is used to simulate the presence of many carriers of random amplitude and phase.”
NPR Measurement Setup
Tune RX to fnotch

18. No clear correlation vs. IM3DR A new “numbers race?”
No clear correlation vs. IM3DR
A new “numbers race?”
IC7700
IC7800 K3
Noise Power Ratio (dB) (VA7OJ)
IC7600
IC9100
FT950
TS590
KX3
FT1KMP-V
IC7000
Flex6700
FTDX3000

19. Listening Fatigue How the Radio “Sounds”
Commonplace “10% THD” spec produces tiring audio
Distortion -20dB from desired signal
Example
IC756 Pro III must be driven into clipping to meet the 2 W into 8 ohm brochure spec.
Many audible spurs
Spurs disappear at lower audio output
<0.1% distortion
Easy to listen for long periods

20. Listening Fatigue How the Radio “Sounds”
Early K3 users complained about “scratchy” audio
40dB down = 1% distortion
Many audible spurs
Adding output choke attenuated spurs
0.1% distortion
Easy to listen for long periods

21. AGC Controls C L Purpose
Reduce distortion
Prevent damage to operator!
Implementation: reduce gain in presence of strong signals
How fast and how much?
Then what?
Optimizing AGC parameters key to performance in wide range of signal environments
e.g., shape of decay action can affect AGC-related IMD C L

22. AGC Control Examples
AGC Threshold
AGC Slope C L

23. AGC Response to Impulse Noise
Slow AGC recovery = poor copy
Faster AGC recovery = better copy

24. Transmitter-Specific Criteria Know the properties of your transmitted signal
CQ WW rules: “Signals with excessive bandwidth (e.g., splatter, clicks)” may disqualified for unsportsmanlike conduct”
SSB: optimize audio chain for communicating effectiveness
Mic: “pin 1” problem
Frequency tailoring: accentuate the positive, eliminate the negative
Amplitude compression: AF vs. RF, level
Background noise: clean transmission and clean reception (AGC)
CW: control rise/fall for “appropriate” bandwidth
Digi: internal vs. external signal generation
ALC behavior
(ATU matching range)

25. Transmitter: ARRL Lab Test Data* Revealing side-by-side comparisons
60WPM Keying Spectral Data
* Mfgr data for Flex

26. CW Rise Time A Little Goes a Long Way
1 “dit” time = 1.2/WPM (W5ALT)
30WPM  1 dit = 40ms
50WPM  1 dit = 24ms
10ms rise, fall fast enough!
TR=3ms
TR=10ms

27. ALC ALC too fast: distortion, IMD
Rig power set to 50W
ALC too fast: distortion, IMD
ALC too slow: overshoot could damage linears that only need 40 to watts of drive
ALC overshoot often worse at reduced power
ALC “artifacts” can be very troubling
No ALC
ALC Half Scale
60 dB down 1.8 kHz away
4 kHz -60 dB

28. PC-to-Rig “Direct” Interface Example
Analog Interface: Line In / Line Out
“Soundcard” digital modes
SSB “digital voice keyer” (DVK)
Digital voice (e.g., FreeDV)
Digital Interface: RS232, USB, FW
CW: LPT is dead!
SSB: built-in DVK
Digi: “native” DSP capabilities

29. Soundcard-to-Rig Interface Example
Isolates transmit and receive audio
PTT, CW, FSK rig control
COM or USB
Essential: compatibility between interface S/W, OS, interface and rig

30. Ergonomics Access to radio controls
Setup: menu confusion?
Most-used operational controls
Knob/button/readout size, spacing, grouping
Confounded multi-functions?
Visibility from operating position
Display – too “busy?”
Controls – label size, color?
Keyboard-radio reach fatigue
Physical size, weight
Where is the radio?
ergo.human.cornell.edu/AHTutorials/typingposture.html

31. “Intangibles” Reliability Serviceability
What breaks?
How often?
Serviceability
Foreign vs. domestic service depot
Discontinued support
ROHS and older radios
Manufacturer, distributor longevity
“Crowd” support and online discussion groups

32. Decisions, Decisions, Decisions
There’s a lot to consider when choosing an HF transceiver
Winner may not be obvious
Make a list of your priorities
“Score” candidates against your priority list
Tally up the score to select a winner…
… or choose a different radio for “intangible” reasons
“I just had to try that radio!”
Parameter
Importance (1-5)
Score
(1-5)
Parameter Score A 5 4 20 B 16 C 3 15 D 2
Total 55