Wednesday, July 04, 2018

QRP Low pass filters with surface mount on veroboard

Ross, VK1UN, has been experimenting with generating WSPR RF using the FL2K VGA dongle. The waveform is pretty rough and of course a low pass filter is required. His solution is mechanically very neat I think. Here's a 160m low pass filter.

The design and simulation of the 160m filter. Capacitors used were 2200 plus 220 = 2420 and in the T 2200 plus 100 = 2300.

He builds on veroboard and uses PCB mount SMA connectors at each end. The tracks are cut under the surface mount inductors. Very neat.

In the end these get boxed up. Ross has modified fl2k_file to use any of the three colour outputs so he can transmit on three different bands.

Nice work!

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