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

Which HF Transceiver is Best for Me?

Brian Machesney, K1LI

What's the Best HF

Transceiver for Me?

Tips on Radio Selection Strategy

Brian Machesney K1LI

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!

Reference SourcesMost 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

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!

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, email 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!

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”

Price and FeaturesA Balancing Act

• Price• 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

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

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 submissionsPower CW SSB

High 3011 (41%) 3240 (41%)

Low 3821 (52%) 4337 (55%)

QRP 505 (7%) 344 (4%)

Simplified Receiver Block DiagramWhat Could Possibly Go Wrong?!• Active stages are not

perfectly linear• Active and passive

stages can overload• Mixing is multiplication:

inherently nonlinear!• Mixers mix everything

at their inputs

Local Oscillator

IF Amp, Detector

Audio Amp

Preselector IF Filter

Antenna

Speaker

RF Input

Local Oscillator

Image

Desired IF OutputAm

plitu

de

Frequency

IF Filter Passband

Mixers Mix Everything at Their InputsPhase 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

RF

LO

Image

Desired IF Output

Ampl

itude

Frequency

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

RF

LO

ImageDesired IF Output

Ampl

itude

Frequency

Step Atten

Receiver 14.02314.027

14.025MHz

ANT

Audio Distortion

Meter

Low-noise

XTAL Osc

SPKR

Measurement Setup

TS590

IC7700

IC7700

FTDX3000

IC9100

TS990

TS990

Flex3000Eagle

TS590Flex5000

FTDX5000

KX3

K3?

Flex6300

Flex6700

Pric

e* (U

SD)

756P2(IR)

IC7600

K3

RMDR (dB) = SRF (dBm) - MDS (dBm)

Notes:* RED = retail,

BLACK = used

Intermodulation Distortion (IMD)• “…range of signals that can be tolerated by the [receiver] while producing essentially no undesired spurious responses.”

RF1 2

LO

ImageIMD 2 1

Desired IF Out

1 2 IMD

Ampl

itude

Frequency

Hybrid Combiner

Receiver 14.002

ANT

Audio Distortion

Meter

RF Gen 214.000

SPKR

2-kHz Measurement Setup

Signal Analyzer

Hybrid Combiner

RF Gen 3 14.002

Step Atten

RF Gen 113.998

IC7000

FT2000

FT1000D

FT1KMPV(IR)

IC756P

FT1KMP(IR)

756P2 TS590*

IC7700*

IC7700*

IC7800*

K2*

OmniVI+

FTDX3000*

IC9100

TS990

TS990

Flex3000*

Eagle*

ArgVI*

TS590*Orion

OrionII

Flex5000

FTDX5000*

KX3

K3

Flex6300

Flex6700Pr

ice*

* (U

SD)

756P2(IR)

IC7600*

K3*

OmniVII

IM3DR (dB) = SRF (dBm) - MDS (dBm)

TS830S/YK88

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

IC7000FT1KMP-V

IC7700

IC7800

FTDX3000

IC9100FT950 TS590

KX3

Flex6700

Noi

se P

ower

Rati

o (d

B) (V

A7O

J)

IC7600

K3

• No clear correlation vs. IM3DR• A new “numbers race?”

Listening FatigueHow 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

Listening FatigueHow 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

AGC Controls• 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

AGC Control ExamplesAGC Threshold AGC Slope

C L

AGC Response to Impulse Noise

Slow AGC recovery = poor copy Faster AGC recovery = better copy

Transmitter-Specific CriteriaKnow 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)

Transmitter: ARRL Lab Test Data*Revealing side-by-side comparisons

* Mfgr data for Flex

60WPM Keying Spectral Data

CW Rise TimeA Little Goes a Long Way

TR=3ms

TR=10ms

• 1 “dit” time = 1.2/WPM (W5ALT)

• 30WPM 1 dit = 40ms• 50WPM 1 dit = 24ms

10ms rise, fall fast enough!

TR=3ms TR=10ms

ALC

• ALC too fast: distortion, IMD• ALC too slow: overshoot could

damage linears that only need 40 to 60 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

Rig power set to 50W

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

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

ErgonomicsAccess 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

ergo.human.cornell.edu/AHTutorials/typingposture.html

Where is the radio?

“Intangibles”

• Reliability• 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

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 4 4 16

C 3 5 15

D 2 2 4

Total 55