Pulse generator for Linrad

Linrad (Linux Radio) is a very powerfull piece of software that, in combination with suitable hardware, forms a SDR-receiver. I use it for 144 MHz adaptive receiving by using my duo channel Javornik EME transverter (which converts 144 MHz to 14 MHz) combined with an Afredi 822x duo channel SDR receiver. The Afredi sends it’s signal to Linrad and from Linrad it goes via timf2 to MAP65.

Linrad contains a noiseblanker which become very effective and smart once calibrated. Leif describes on his webpages (www.sm5bsz.com) a design and a tool to calibrate the noiseblanker. I have build this noiseblanker in early 2016. Meanwhile there are various ways to achive adaptive receiving such as the IQ and IQ+. That’s why the PCB on the picture and the PCB design are different. When boxing up the PCB some years later I added the extra needed capacitors in the schematics and pcb-layout.

Noiseblanker schematic including the extra switchable capacitor for IQ, IQ+ and IQ+XT
Scale: 3:1
Scale: 3:1
EME in the early morning of october 22nd 2016, using Javornik 144/14, Afredi 822x, Linrad and MAP65