Icom IC-703

Icom’s 10 W QRP radio for HF (and 6 m on the Plus) with a built-in antenna tuner, low current drain and a 9–15.8 V supply range: the small 706-size body, built for portable, mountain-top and field operation.

Power 10 W

Tuner ATU

Supply 9–15.8 V

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Front view of the Icom IC-703 transceiver

Overview

The IC-703 arrived in 2002 as Icom’s low-power (QRP) portable radio. Its body is the same size as the 706 series (167 × 58 × 200 mm), but it weighs 2 kg and gives up to 10 W instead of 100 W. In return it runs on 9 to 15.8 V, draws little current on receive and, above all, has a built-in automatic antenna tuner, so a random wire or an imperfect dipole is enough to get on the air.

IC-703 or IC-703 Plus?

The Plus, released in 2003, adds 6 m. The first US-market IC-703s were HF only, while most European versions sold as IC-703 already had 6 m. Both panels just read “IC-703”; the surest test is whether 50 MHz can be selected. DSP (noise reduction and auto notch) is built in on some versions and needs the optional UT-106 on others.

Power and batteries

Above 11 V it gives 10 W. Below 11 V it switches to “battery mode” and limits power to 5 W (also 5 W at 9.6 V). That makes a 4-cell LiFePO4 battery (about 13 V) its best companion. With the backlight off and power saving on, receive current drops to about 0.3 A; transmitting at 10 W draws about 2.5–3 A.

Strengths

Built-in automatic tuner for HF and 6 m; the ARRL lab saw it match loads up to about 8:1 SWR
Low current drain and a wide voltage range, good for batteries and solar panels
A receiver with better dynamic range than the 706 series (according to QST’s measurements)
Good frequency stability thanks to a built-in TCXO (±0.5 ppm)
Detachable panel, CW memory keyer, VOX, compressor and tone squelch

Weaknesses and common faults

Only 10 W, which is little in poor conditions or for SSB pile-ups
At 2 kg it is heavier than newer QRP radios for hiking and SOTA
The CW keyer can lock up or send false elements from RF on the key line, especially with end-fed antennas; Icom issued a bulletin, and owners fix it with a ground wire from the key jack to the chassis
On some early units the driver transistor failed because of incorrect bias
Only one optional filter slot, and the microphone jack under the front panel is awkward

Portable tips

Keep the supply above 11 V to keep 10 W; the 9.6 V BP-228 pack puts it in 5 W mode.
The internal tuner is specified up to about 3:1 SWR on HF (2.5:1 on 6 m); never transmit without an antenna.
The tuner remembers its settings per 100 kHz; enable PTT TUNE so it retunes when the frequency changes.
In battery mode (below 11 V) the external AT-180 and AH-4 tuners do not work.

Photos: iz1ksw via Flickr, CC BY-SA 2.0 (cropped).

Specifications

Introduced: 2002 (Plus with 6 m from 2003)
Transmit bands: 160–10 m (all HF bands); 6 m on the Plus and most European versions
Receive range: 30 kHz – 60 MHz (depending on version)
Output power, HF and 6 m: 0.1–10 W at 13.8 V; 5 W max below 11 V (AM: 4 W)
Output power, 2 m: No 2 m band
Output power, 70 cm: No 70 cm band
Modes: SSB, CW, AM, FM and RTTY
DSP (noise reduction, auto notch): UT-106 (NR and ANF); built in on some versions, optional on others
Tone squelch (CTCSS): Built-in encoder and decoder, with tone scan
Memory channels: 105 (99 regular + 6 scan edges)
Receiver: Double-conversion superheterodyne
IF frequencies: 64.455 MHz and 455 kHz
SSB sensitivity (preamp on): HF: 0.16 — 10 m: 0.13 µV
FM sensitivity on 6 m: 0.25 µV (12 dB SINAD)
Frequency stability: ±0.5 ppm (built-in TCXO)
Power supply: 9–15.87 V DC, negative ground
Current drain: Transmit: about 2.5–3 A (10 W) — receive: 0.3–1.2 A
Antenna connectors: One SO-239 (50 Ω)
Dimensions (without projections): 167 × 58 × 200 mm
Weight: 2 kg
Operating temperature: −10 °C to +60 °C
Automatic antenna tuner: Built in for HF and 6 m (16.7–150 Ω); external AH-4 and AT-180 supported
Optional filters: FL-52A, FL-53A, FL-222 and FL-257 (one at a time)
Separation cable: OPC-581 (3.5 m) and OPC-587 (5 m)
Optional battery: BP-228 (9.6 V Ni-Cd, 2800 mAh)

Photos

Buying used: what to check

01 Check whether 50 MHz can be selected; that tells you whether it is a Plus or a European version with 6 m. Both panels just read “IC-703”.
02 With a 13.8 V supply and a dummy load, check for 10 W on several bands; low or no power can point to a failed driver transistor.
03 Try the internal tuner on a mismatched antenna or a wire and see that it tunes quickly.
04 If you work CW, try the keyer with an end-fed antenna; a locking keyer is the known RF problem.
05 Find DSP (NR and ANF) in the menu to confirm the DSP unit is fitted.
06 The BP-228 pack that comes with old units is usually worn out; do not count it in the price.

FAQ

What is the difference between the IC-703 and the IC-703 Plus?

The IC-703 Plus adds 6 m. The first US-market IC-703s were HF only, but most European versions sold under the same name already had 6 m. Everything else is the same.

Which battery should I use?

A 4-cell LiFePO4 battery (about 13 V) is the best choice: it stays above 11 V, so the radio keeps 10 W. With a 9.6 V pack, power stays at 5 W.

Which antennas can the internal tuner match?

Antennas between 16.7 and 150 Ω on HF, roughly up to 3:1 SWR. For very long or badly mismatched wires, the external AH-4 is better.

Does it work on 2 m?

No. The IC-703 covers only HF and, on the Plus, 6 m.

Questions about the IC-703?

Ask on Telegram or by email — common questions are added to this page.

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