Putting the DX-SR9 in SDR Mode
The DX-SR9 is placed into SDR mode by pressing the Mode button until the display shows FM mode. To complete the process you must then press the FUNC key and then the Mode key to put the DX-SR9 into SDR mode. The front panel display will indicate SDR displayed in large letters. At this point, the DX-SR9 effectively becomes a black box SDR radio. All front panel controls are disabled including the front panel mic jack. The DX-SR9 can now be controlled only by commands sent to the ERW-7 cable and the software. This is good in a way since you can’t accidentally make changes to the radio by bumping a knob. However, it would have been kind of nice to leave the VFO knob active so you could use the VFO knob to tune the SDR software if you wanted to. It would also been nice to not disconnect the mic jack. However, it’s not really that much of a problem.
KGTRX is included on a CD that ships with the DX-SR9. You might want to check Alinco’s Website to see if a newer version is available. The good news for you that may have used KG-SDR with your Alinco DX-R8 or DX-X11 receivers, is that KGTRX is a much improved application for SDR use with the DX-SR9. While the KG-SDR was extremely basic and offered very few features, you will find that KGTRX offers more features and customization and supports the DX-SR9 very well. It’s still a bit on the plain side and doesn’t offer all the bells and whistles of some 3rd party offerings, but it gets the job done. Plus, for those new to SDR radio, it’s very easy to setup and use. Even though the specifications call for a minimum of a Core I5 processor, it was tested on a Windows 8.1 Core I3 machine and a dual core Atom based laptop with no issues. The Core I5 recommendation is primarily based on helping to reduce transmit audio latency.
Setting up KGTRX is very simple. Under the Settings / Device menu you will need to set the RX IQ Signal input and the Speaker Out to match your soundcard settings. If you are going to transmit you will need to set the TX microphone input and the IQ signal output to match the appropriate soundcard settings. Finally you will need to set the RS232 Port setting to match you the serial port setting of the ERW-7. If you don’t know, you can always check under the Device manager for reported serial ports. If your PC is pretty simple as far as sound cards and serial ports are concerned, it may auto detect these settings. Once these are all set, you are good to go.
One big advantage of KGTRX over 3rd party programs, is that it can support features that are unique to the DX-SR9. For example it supports switching between transmit and receive, AGC settings, Power Level settings, RF Gain settings, and External tuner. Even though you can use 3rd party SDR programs they probably won’t support these features on the DX-SR9.
The KGTRX displays both a spectrum display and a waterfall display while using the the DX-SR9. Tuning can be accomplished by several ways. You can directly input the frequency and the use the mouse scroll wheel for fine tuning. You can also click on the spectrum display or waterfall display to set the receive frequency. A nice feature is that by right clicking on the mouse, you can move very quickly through the spectrum display tuning. This allows you to quickly sample each signal. The fine tuning step size is adjustable from 1Hz to 20Hz. The listening frequency , s-meter, and filter settings are shown at the top of the screen. Of course there are buttons and sliders for volume, squelch, and transmit. KGTRX offsets the receive signal away from the center spike to help eliminate any interference that may be generated from the spike. Turning on transmit, KGTRX sends the matching the transmit frequency and mode to the DX-SR9 and audio is sent from the PC to the MOD jack.
KGTRX offers several DSP functions. The IF and RF filters can be set to several presets by the software or you can customize your own. There is a non-adjustable noise reduction filter, which does a reasonable job of reducing background noise. There is also an automatic notch filter which is pretty effective at removing an unwanted tone in the signal. The 3D button provides a pseudo stereo effect which will push the received audio a little more forward. This actually very useful for making weaker signals more present.
Some additional features available in KGTRX is an IQ and Wav recorder. This can always come in handy in various ways. The IQ recorder will allow you to record the entire 48KHz spectrum for playback later in KGTRX. The Wav recorder will let you record the current receive frequency for general playback with most media players. There is a spreadsheet style frequency memory feature to allow you to create and save frequency presets. A nice touch is that you can move to the frequency you want to save and activate the memory feature and simply click add frequency and the frequency and all of it’s setting are stored. You can also give it an alphanumeric tag. At this writing, the frequencies can’t be sent directly to the radio for storage. There is a Tune button to activate the Alinco external antenna tuner if you have it. The CW key, basically lets you use the mouse button as a cw key if you want. Under the settings menu, KGTRX will allow you to do a few customizations to the display like changing colors of some components and positions of some of the display elements. The gain settings let you tweak the waterfall gain, input gain, mic gain, and output gain. The misc settings allow the user to change the behavior of the mouse wheel, beep volume, filter shape, CW tone, recorder playback behavior, and the IQ tuning area.
Overall, KGTRX ticks most of the boxes and makes SDR easy to operate for beginners or just as an everyday SDR program for casual use for more experienced users. More than likely this will be the program that most of you will use with DX-SDR9.