How to use a RTL-Dongle or SDRPlay with WSJT MAP65.

(This method also works with CW Skimmer).

I'm using a LNA followed by a bandpass filter in front of the RTL Dongle. HDSDR acts as a front end for the dongle and sets the centre frequency. For 2m EME this is usually 144.120MHz.

HDSDR functions as the frequency control for the dongle. It sends IF IQ at 96kHz to MAP65 (or CW Skimmer) using a virtual audio cable.

This assumes that you already have the SDR installed and running with HDSDR OK.

Once you have HDSDR working on 2m as a receiver calibrate the frequency.

In the HDSDR (F5) Soundcard settings menu select your virtual audio cable in the RX Output (to Speaker) menu.

You can see I've got 3 VB Audio virtual cables installed here and I'm using Cable A.

In the(F6) Bandwidth settings menu choose 96000 Output

In the (F7) Options/Ouput Channel Mode for RX choose IF as I (left)/Q (right)

Go into Windows Control panel and ensure that the virtual audio cable is running at 96kHz sample rate. Higher sampling rates will work too with VB Cable because it automatically resamples on the input and output if sample rate is different to the rate the cable is running at internally. If the sample rate is less than 96kHz you'll find the bandwidth in MAP65 restricted.

Start HDSDR running (F2). Set the receiver frequency to 144.120. You can minimise HDSDR if you want (F2).


Install MAP65 if you haven't already done so and configure it for your station.

In MAP65Setup menu/Options choose IO Devices

In Input source:

Select Soundcard

Select your virtual audio cable from the dropdown

Select 96kHz Sample Rate

With the RTL Dongle I had to select +10dB to get the recommended 20dB level. With the SDRPlay I set the level using the gain control in the ExtIO menu.

Provided there is activity you should now start seeing stations appear in the MAP65 band map and message windows.

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