Best of Both Worlds

Best of Both Worlds: K3 with Win4K3 Panadapter

I have several rigs including two modern SDR transceivers, a Hermes Lite 2 and a SunSDR2 DX, that are not standalone but communicate to computer software by Ethernet. I enjoy the SDR’s spectrum displays and point and click tuning. The SDRs have extensive audio processing and excel at digital modes and SSB, CW not so much. Neither are QSK and both suffer from sidetone lag, which has to be addressed.

CW is clearly an afterthought for the HL2 which has a straight key port but no keyer. sidetone lag makes sending impossible with any of the many software available for it except SDR Console by Simon Brown, of Ham Radio Deluxe fame, which can keep up with my slow to moderate speeds. SDR Console also provides an audio peaking filter (APF) for CW and a seperate small spectral window that displays the filter width spectrum that helps manual tune. I use a stand alone keyer that I can connect to a PC app for control and messages.

The SDR2 DX2 is only supported by its own software. It does have a built in keyer. If used with a fast, gaming type computer with tweaked OS settings its lag is acceptable for my moderate speeds. It also has APF and a DSE feature that pans the CW signal from side to side as you sweep past the frequency, which is nice when using headphones. To fine tune I find myself zooming in on the panadapter and later zooming back out. Again you need a separate app for messages. I use SDC (Software Defined Connectors) which also provides a skimmer and a host of other featiures.

Sometimes you just like to tune or set filters with a knob, which brings me back to my venerable Elecraft K3. Mine is a very early model (#70) from 2007 with updates including the K3IOB with soundcard and USB interface but not the K3S synth boards. Elecraft makes rigs that are great for digital, SSB and CW. It still is in the top rank of SEI receiver ratings. Its superhet design is relatively immune to overload (a concern with SDRs) and it features sets of brick wall crystal roofing filters. For CW it has QSK and APF and DPB (dual pass band) digital filters. There is an on display CW tuning indicator and a one button CW tune function that precisely tunes itself to a signal. My K3 has the optional IF interface and I have an old LP-PAN panadapter interface. The signal goes from the K3 to the LP-PAN to a Behinger 192 ksps USB audio device. In the past distant I used separate panadapter software, but it was such a pain that I stopped using it for years.

Enter a great solution – Win4K3 software. This software seamlessly knits K3 control with a spectrum display. You get a modern spectrum and waterfall with point and click tuning and you keep your old friends the on radio controls. Since the 2 channel IQ is at 192 ksps you get up to a 192 kHz wide display. I can point and click to a CW signal and then hit the CW tune button to be spot on.

If you don’t have an LP-PAN you can use an SDRPlay RSP1a SDR receiver instead. At about the price of the USB audio device it replaces both the LP-PAN and the USB audio device. Win4K3 also knits this ensemble together easily. Win4K3 talks directly to the RSP1a drivers to knit it all together.

But wait – there’s more. Don’t have a K3 with IF option? You can use the same setup of Win4K3 and a your computer soundcard with a KX3. If you want a wider panadapter bandwidth you can use an external USB audio device. Nothing else is needed.

Below is a pic of the system with the monitor low and the K3 in easy reach above it. The LP-PAN and USB soundcard are peaking around the right side. In addition to the control and panadapter windows there is a terminal window open that controls messages and displays K3 full decodes. As noted in the bar on the top of the terminal, it auto logs to DX-Keeper, my logger of choice.

Here is a zoom in on the control and panadapter windows. The control panel is logically laid out with controls grouped by function. You can tune by selecting a digit in the frequency display and using the mouse scroll wheel or clicking on and pulling the slider in the frequency display panel. You can also pop open a window and directly enter a frequency. You can also reach out and turn the tuning knob on the K3. I A-SPOT tuned so I’m not exactly at 7.031. The TX Equalizer settings are shown. A click brings up the RX Equalizer settings. You can also bring up a window that displays and allows you to set all of the K3 menu items.

The range and span of the panadapter are easily set. As expected, a left click will take you to that frequency. A right click lets you easily set the tuning rate. You can select to display centered on either VFO. There are a set of user defined spans toggled by a row on buttons just at the bottom of the window. If you have ClubLog set up its spots will display on the Win4K3 spectrum.

With a full featured spectrum scope combined with a high performance transceiver with QSK and other CW features and actual knobs the Elecraft K3 with a panadapter integrated by Win4K3 is the best of both worlds.