Cheap SDRs 2m DX.

I have used a Funcube Dongle, RTL Stick and most recently the SDRPlay RSP for 2m DXing. Both the RTL dongle and the SDRPlay RSP allow me to see the whole 2MHz of 144MHz, or normally more usefully, the whole of the DX end of the band. The station configuration is the same for any of these SDRs.

The SDRPlay or RTL Dongle with MAP65 or CW Skimmer

144.150 to 144.400 with the SDRPlay RSP during the May 2016 144MHz activity contest. Software is SDRConsole V3.

Quickstart guide to SDR Console and the SDRPlay RSP

• Transceive operation with the station rig, an IC746. Simon HB9DRV's SDRConsole V3 software controls the frequency of the SDR and the Icom via CIV. So if I turn the tuning knob on the Icom the SDR VFO follows.
• Click on a signal in the panoramic display the rig jumps to that frequency.
• Additional and comprehensive IF filtering and demodulation provided by SDR-Radio.

I've been using this setup during openings on 2m in the past couple of years and it has been completely reliable. Instead of constantly tuning up and down around the calling channel I can see signals the moment they appear. Just click, the Icom jumps to the frequency and pounce! There are several nice QSOs in the log as a result of spotting DX calling CQ away from 144.300 that I am sure I would have missed without SDR.

A simplified block diagram of my station configuration.

• The antenna is a 9 element M2 for terrestrial work, or 2x 9 element for EME.
• GS31 amplifier for 2m.
• The LNA is a DEMI HEMT kit. The LNA could be placed at the mast-head but I only have short runs of Heliax and so it is in the shack.
• The Icom IC746 has been modified for a separate receive input. I have mounted an extra N sockets on the back panel using the ventilation slots. There was no need to drill the back panel.
• The 144MHz receive line after the LNA is split and fed into the Icom and the SDR. I'm using a simple 2-port Wilkinson divider made from 75R coax cable.
• The SDR has a long USB cable to keep it away from the computer hash.
• All cables are treated with ferrites. NB use more than one turn, or of the cable is too thick, use several ferrites on a cable.
• The shack PC uses an Intel i5-2400 quad core with 16GB RAM and runs under Windows 10 Pro 64bit.
• I can choose whether I listen to the rig or to the output from SDR-Radio on the computer or both.
• At the moment WSJT and other digital modes use the conventional rig audio fed into the Delta 44 soundcard. The Delta 44 also provides TX audio for digital modes via an audio interface box.
• The station is sequenced using a W6PQL board.

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