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Regular reports of my grabber activity and that of others, plus information on QRSS software, hardware and technique that comes my way

Tuesday, February 19, 2019

Using receivers on the KIWI SDR Network as remote grabbers

I had seen the KIWI SDR Network before but didn't realize just how good the receivers are.  After some experience I find that they are generally as good as a "real" receiver and by that I mean a standard HF transceiver such as my TS-440 or TS-480.  I feed the audio from a KIWI receiver into Spectrum Lab and end up with a grabber that looks and works  like the grabber with which I've had success over the years.

The above link will tell you how to find and log onto a given receiver which will open a screen like this one at EA2CQ, after selecting a few parameters in the control panel at lower right :

Figure 1.  KIWI SDR Display



Here is a more detailed view of the important parts:


Figure 2. Setup Details



First, enter the frequency of the center of the QRSS spectrum in the box at the upper left.  For the center frequency I use 100 Hz below the lower edge of the WSPR band which for 40m is 7039.9 kHz.  Then choose "cw" which will select a filter width, 400 Hz which is just right to cover 300 Hz of QRSS plus 100 Hz of WSPR.  I find being able to see some WSPR helpful when there might not be QRSS signals coming thru to have some idea if the band is open or maybe the KIWI station is using a poor antenna, etc.  Note at the top left the filter is shown centered on the frequency chosen.  You may have to use the mouse wheel to adjust the width of the spectrum.  Roll the wheel forward away from you to narrow the spectrum and backward toward ;you to make the spectrum wider.  Start with a narrow view to ensure the frequency is 100 Hz below the WSPR band edge.  You can then widen the spectrum to see what around and in fact go all the way to 0 to 30 MHz coverage without affecting the cw filter.

Then click on "Auto Scale" which usually makes a nice contrastl.  Finally, select a slower speed with "Slow Dev" which has 5 steps.  I find "Slow" or "1 Hz" works best.  These adjustments should give a nice image but you can play with the other controls for tweaking as desired.

At this point you should hear the audio from QRSS/WSPR around 500 Hz.  Now, direct this to your sound card and feed that into a waterfall/specturm analyzer such as Argo or Spectrum Lab you have a working grabber whose images can be uploaded to a web page just as you do with a receiver in your shack....except it is coming from a remote receiver.  Here is an example using a KIWI receiver I like in Tabov, Russia just west of Volgograd:


Figure 3.  Resulting QRSS Grabber Using Spectrum Lab




KIWI SDR is designed to produce audio for the speaker of your computer and it may be tricky to direct this to the sound card.  I use Windows 7 and had to enable Stereo Mix which is sometimes called "Recording What You Hear".  Right click on the speaker icon and select "Recording Devices" then right click on a blank area in the pane and ckeck "Show Disabled Devices" and "Show Disconnected Devices".  Click on Stereo Mix and enable it.  Then in the Audio Device selection of you spectrum analyzer (Argo or Spectrum) select Stereo Mix.

Now you should have a working grabber which I refer to as a "Hybrid Grabber."  This link will show you a map of all known receivers on the KIWI SDR Network.  Click on one and you're off and running.

I now have four images on my grabber.  The third one down is dedicated to KIWI SDR.  As you can see it looks just like the others that come from my Kenwood transceivers.

If you have problems my email is w4hbk@arrl.net

de bill w4hbk

* Select cw mode with receiver set for a cw note of 500 Hz....cw mode is actually in USB
** Offset based on a cw beat note of 500z

ps   here is a table of settings for each band:

QRSS Grabber Settings*

Band WSPR Low Edge QRSS Center Frequency Waterfall Offset**
80m 3570.0 kHz 3569.9kHz 3569.4 kHz
40m 7040.0 7039.9 7039.4
30m 10140.1 10140.0 10139.5
20m 14097.0 14096.9 14096.4
17m 18106.0 18105.9 18105.4
15m 21096.0 21095.9 21095.4
12m 24926.0 224925.9         24925.4
10m 28126.0 28125.9 28125.4


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