Icom IC-7300 HF and 6 Meter Transceiver

Introduction: A Game-Changer in SDR

Calling a piece of technology a "game-changer" is to invoke a cliché of the highest order, but it's difficult to avoid when discussing the Icom IC-7300. A game-changer is usually defined as a product that has the potential to disrupt a market. When a game-changer appears on the scene, competitors are challenged, buying preferences change, and the market veers off in a new direction (the introduction of the Apple iPhone is a classic example).

The game-changing aspect of the IC-7300 is not the fact that it is a software defined radio (SDR). Hams have been exposed to SDR technology for more than a decade, and QST has reviewed several highly competent SDRs from other manufacturers. Instead, what makes the IC-7300 disruptive is that it offers the performance and flexibility of SDR with a touchscreen in a user-friendly package that is unlike any other – and it does this at a price point that is guaranteed to be attractive to a large segment of the amateur community. It's similar in concept and price point to Icom's previous generation IC-7410, but offers more features and better performance in many areas.

SDR with Knobs

For those who may be unfamiliar with the technology, a software defined radio takes the analog signal arriving at the antenna, input and "samples" it at an extremely high rate, effectively converting the analog signal into a stream of digital information. Once a signal has been converted to data, it can be processed by software in ways that are not possible – or at least practical – with analog technology. Any form of modulation can be decoded, noise can be removed (or greatly suppressed), and extraordinarily sharp filters can be applied to the result.

To transmit, the process is essentially reversed. Software massages the desired signal, which is then converted to analog and amplified. In the early days of Amateur Radio SDR, a receiver board performed quadrature mixing on the incoming RF signal, creating in-phase (I) and quadrature (Q) analog baseband signals.

Bottom Line

Icom's IC-7300 is a 160-6 meter, 100 W, software defined radio (SDR) in a conventional package. Aimed at the "entry level" segment of the market, it offers a wide range of features and excellent performance often found in higher-priced transceivers.

Figure 1: Rear Panel Connections

The IC-7300's rear panel features connections for a CW paddle (internal keyer or external key/keyer), an external speaker, ALC and TR switching for an amplifier, remote control via optional RS-BA1 software or an Icom CI-V device, a USB port for radio control and digital mode operation, an ACC socket for connecting a TNC or PC for digital modes, and a jack for connection to Icom's accessory antenna tuners or tuned antennas.

Key Measurements Summary

The following key measurements were taken and are presented in Table 1 and graphical summaries:

Reciprocal Mixing Dynamic Range (RMDR):

• 20 kHz: 114-140 dB
• 2 kHz: 123-140 dB

Blocking Gain Compression (BG):

• 20 kHz: 90-97 dB
• 2 kHz: 95-110 dB

3rd-Order IMD Dynamic Range:

• 20 kHz: 97-110 dB
• 2 kHz: 102-140 dB

Transmit 3rd-Order IMD:

• Values range from -57 dB to -30 dB depending on band and conditions.

Transmit 9th-Order IMD:

• Values range from -47 dB to -35 dB.

Transmit Keying Bandwidth:

• Values range from -80 dB to -150 dB.

Transmit Phase Noise:

• Values range from -110 dB to -150 dB.

Table 1: Icom IC-7300, serial number 02001161

Manufacturer's Specifications: Frequency coverage: Receive, 0.03 – 74 MHz; transmit, 160-6 meter amateur bands. Power requirement: Receive, 0.9 A (standby), 1.25 A (maximum audio); transmit, 21 A at maximum power output at 13.8 V dc ±15%. Modes: SSB, CW, AM, FM, RTTY.

Measured in the ARRL Lab: Receive and transmit as specified. At 13.8 V dc: Receive, 1.05 A (maximum volume); transmit, 18.5 A (typical). Noise floor (MDS) varies by frequency and preamp settings, with values as low as -143 dBm. AM sensitivity: <12.6 µV to <1.0 µV. FM sensitivity: <0.5 µV to 0.25 µV. Blocking gain compression dynamic range: 500 Hz bandwidth, 20 kHz offset, ranges from 114 dB to 123 dB. ARRL Lab Two-Tone IMD Testing (500 Hz bandwidth) shows various IMD levels and dynamic ranges depending on band, spacing, and preamp/IP+ settings, with IMD DR values ranging from 77 dB to 102 dB.

Lab Notes: Icom IC-7300

By Bob Allison, WB1GCM, Assistant Laboratory Manager

The Icom IC-7300 utilizes an RF direct sampling system, where analog signals are digitized early in the signal path. This differs from traditional architectures where the signal path remains analog until later stages. A key component is the analog-to-digital converter (ADC), which can produce intermodulation (IMD) products at low signal levels. To mitigate this, a dither signal (random noise) is added, improving the two-tone third-order intermodulation distortion dynamic range (3 IMD DR). The IP+ feature controls this dither signal.

ADCs have an input signal limit; exceeding this causes an overload state. The IC-7300's ADC threshold is high, with no blocking observed until the threshold level from an adjacent signal is reached. Reciprocal mixing dynamic range (RMDR) and gain compression (blocking) dynamic range figures are reported as very good, with RMDR showing significant improvement over previous models.

The S-meter reading is noted to use a 3 dB/S unit scale, which differs from the commonly accepted 6 dB/S unit standard. The transmitter is described as clean, with low phase noise and reasonable keying sidebands. While transmit IMD third-order products are excellent on most HF bands, fifth and seventh order products are higher, especially on 6 meters. Reducing RF output power on 6 meters can improve these odd-order products.

Power overshoot was observed in SSB mode, occurring very briefly (less than 2 ms). Icom recommends operating with the speech compressor off to minimize this when using an external power amplifier. A potential concern for users with fast-switching amplifiers is the 3 ms RF output at the antenna jack after the amplifier key line opens, which could cause hot-switching issues or key clicks if not managed with transmit delay settings.

The noise blanker performance is highly praised, effectively eliminating most clicks and pops. The noise reduction feature also works well without introducing excessive distortion. AGC is highly adjustable with FAST, MID, and SLOW settings, with time constants adjustable from 0.1 to 8 seconds depending on the mode.

Filtering is adjustable via the touchscreen, with three filter selections and adjustable shape for each operating mode.

Transmitter Performance

The transmitter offers power output from 2-100 W (1-25 W for AM). Spurious-signal and harmonic suppression is rated at >50 dB (1.8-28 MHz) and >63 dB (50 MHz). SSB carrier suppression and undesired sideband suppression are both rated at >50 dB.

Third-order intermodulation distortion (IMD) figures are detailed, showing typical values for HF bands and specific measurements for 50 MHz. CW keyer speed ranges from 6 to 48 WPM with iambic mode B support. Transmit-receive turn-around times (PTT release to 50% audio output and transmit delay) are also specified.

Transmit Dynamic Testing: Power output is typically 0.7-104 W for HF and 0.5-97 W for 50 MHz. Spurious-signal suppression is typically 64 dB for HF and 76 dB for 50 MHz. SSB carrier suppression and undesired sideband suppression are both >70 dB. Third/fifth/seventh/ninth order IMD for 100 W PEP on HF shows typical values like -42/-38/-46/-57 dB, with worse case values noted for 10 meters. On 50 MHz, typical values are -26/-37/-39/-44 dB (100 W) and -33/-37/-44/-62 dB (80 W).

Digital Modes and Connectivity

The IC-7300 includes a built-in RTTY decoder, which performed well in testing, displaying decoded text in a window and allowing saving to an SD card. The RTTY feature also supports transmit memories for canned messages, useful for DX hunting.

For general digital operation, the IC-7300's USB connection is highlighted as the primary method. It handles transmit/receive audio and keying smoothly over a single cable, acting as a USB Audio CODEC and a virtual serial COM port. Users need to select this "sound device" in their software setup.

The review mentions using the USB connection for RTTY contesting with MMTTY software, reporting perfect performance. A YouTube video link is provided for setting up MMTTY with the IC-7300: https://youtu.be/ZCkiuzAMUZI.

For those preferring traditional interfaces, the transceiver still offers a multipin accessory port on the rear panel.

About the Screen and Interface

The IC-7300's touchscreen is praised for being bright, easy to read, and functional for displays like the waterfall and spectrum scope. Both scopes are adjustable, allowing users to zoom in on signals or view audio characteristics. Tapping a signal on the scope directly tunes the transceiver to that frequency.

Passband tuning is rendered graphically, showing the effect of knob adjustments as an animated graphic. The SWR graphing function acts like an antenna analyzer, allowing users to set frequency parameters and press the TRANSMIT button repeatedly to measure and plot SWR. The built-in antenna tuner supports mismatches up to a 3:1 SWR, with an "Emergency Mode" that can handle up to 10:1 SWR at reduced RF output.

For users wanting a larger display, Icom offers the optional $100 RS-BA1 remote control software, which allows transceiver control and screen display on a computer monitor, including remote operation via the Internet.

Conclusion: A True Game-Changer

The Icom IC-7300 is deemed a true game-changer, meeting the criteria by blending the familiar ergonomic design of an analog transceiver with software-defined radio technology at a moderate price. The approach is expected to spread rapidly to other models, and its introduction may be seen as a pivotal moment in amateur transceiver design.

Manufacturer Information:

Icom America
12421 Willows Road NE, Kirkland, WA 98034
Tel: 800-872-4266
www.icomamerica.com

For a video overview of the Icom IC-7300 HF and 6 meter transceiver, click here.

Distributors:

THE NETHERLANDS | Roermond
Tel. +31 (0)475-327390
www.classicinternational.eu

GERMANY | Mnchengladbach
Tel. +49 (0)2166-33061
www.classicinternational.eu