The WiNRADiO WR-G313i is a software-defined high-performance HF receiver (9 kHz to 30 MHz, optionally extendable to 180 MHz) on a PCI card.

My version covers from 9kHz to 180MHz, without gaps. It does this in operator set steps, the smallest being 1Hz and with a 1Hz readout. It is capable of being accurately calibrated and can display frequency accuracy to 0.1Hz via the test facility.

It has so many attributes that this introductory article cannot cover, but I hope to cover the essentials of immediate interest.

Hardware

The PCI card plugs into an available slot of an IBM-compatible PC

The receiver is extremely sensitive, making it possible to comfortably read CW signals under 0.05 µV input levels, yet featuring a respectable 95 dB dynamic range making the receiver resistant to strong signal overload within the limits of the 15kHz roofing filter. It has RF AGC with adjustable attack and decay values, and can be switched off if required so that the gain is then controlled manually.: The fully calibrated S-meter shows the received signal levels in dBm, µV or S-units, down to the 140 dBm noise floor. There is also an averaging feature which allows stable readings of pulse or short duration signals.

There are numerous demodulation modes, continuously variable IF bandwidth 1 Hz to 15 kHz (in 1 Hz increments), a 20 kHz wide real-time spectrum analyzer with 16 Hz resolution, noise blanker and notch filter.

The notch filter is fully variable in frequency and width to assist in eliminating annoying interfering signals or heterodynes.

There is also an integrated recorder, making it possible to instantly record and playback the received signal.

Apart from audio recording and playback, the receiver can also record an entire 20 kHz wide IF spectrum, making it possible to thoroughly analyze the received signal, and "re-receive" the same signal again and again with different IF filter bandwidths, notch filter, noise blanking or demodulator settings, to arrive at the best possible reception of weak or interference-prone transmissions.

In addition to the real-time narrow-band spectrum analyzer, there is also a wide-band spectrum analyser which contains additional professional instrumentation facilities: the ability to display minimum and maximum spectrum sweeps, search for peaks, average spectra, save and print spectra, marker mode, etc.

Another useful feature, previously unavailable with receivers of this price class, is a test and measurement facility, performing measurements on the received signal including frequency accuracy, amplitude modulation depth, frequency deviation, THD (total harmonic distortion) and SINAD. An audio spectrum analyzer is also included, making it possible to observe the demodulated spectrum in real-time with a resolution of 5 Hz.

This is the screen view of the receiver which can be controlled by keyboard or mouse. I also added a Griffin rotary knob which simulates the tuning on conventional receivers.

Software
The WR-G313i software contains numerous advanced features, many tuning and scanning options, virtually unlimited memories and a rich on-line help facility: Free upgrades are made available through the software, which is readily available for download from their site.

The initial software has been updated following feedback reports from users and many “wish list” items have been added.
Two forums are available to discuss the receiver:

http://groups.yahoo.com/group/WiNRADiO_G3_Series/
http://groups.yahoo.com/group/winradio/

How does it perform?
My inputs vary from passive wire aerials, active aerials and loops. My favourite loop being the Quantum Pro ferrite loop, hand built by Gerry at Radio Plus in Florida. More on this in future reviews!

I find that it works well with my G313i, covering 150kHz to 2MHz so also useable for NDB work.

I have not measured the G313i performance but having compared it with my Fairhaven RDX500, Icom IC-R8500, and Lowe HF225, it remains my main receiver.

With the fully adjustable bandwidth and pass band tuning I can separate many of the 10kHz signals from among the 9kHz European signals that dominate.

It handles strong local signals alongside weaker signals as the RF AGC and sound AGC are fully controllable. AGC attack and delay are also pre-settable to taste. Modes available are AM, AMS, LSB, USB, DSB, ISB, CW, FM.

Audio quality is as good as your PC audio, with DRM bringing an added quality to the hobby.

As the audio does not rely on the PC it can be fed directly to an external amplifier for added fidelity.

I find it easy to scan or step channels with unlimited memories holding a few or all of the frequencies of interest .

Mike Simpson in Australia created a useful free memory program called WinRadHF - this program allows you to import virtually any .csv file and export it as a G303 or G313 .g3m file. All you need to do is tell the program the order of the columns in your .csv file and it exports the required output.

Ability to record at Intermediate frequency for revisiting, re-examination or create wave files for archiving is a boon as it means that a separate recorder is not required for unattended monitoring.

This facility has been a boon in recording long MSF test transmissions for later or future examination. This is also useful for unattended use for capturing MF DX during the night or special occasions where a the possibility of a rare signal may appear and so relieves the tedium of sitting and waiting.

To make good use of this recording facility a large extra disc drive will be needed due.

I list below the claimed measurements but in later articles I will provide my measurements and comparisons with other receivers.

WR-G313i Specifications

Here is a screen shot of the G313i in action receiving the PAT beacon on 0.499290MHz, showing the test facility and the result on Spectran display.

This receiver will interface with Audio Spectrum software where carrier monitoring is required and the long term frequency stability allows accurate traces to be recorded where carrier offset measurements are to be made.