Welcome to PA0SIM´s home page



Triggered by the magic of radio I started as a SWL in 1973. Got my full license in 1975.

My main ham radio interests are radio technology, shortwave propagation and CW.

Doing practically 100% CW on HF (AGCW #2867, FISTS #18854), mainly rag-chewing, some DX-ing (DXCC) and now and then a contest (e.g. PACC). Only my 2m transceiver has a microphone for local chats. Always using QSK.

Operating with the excellent FTDX5000 equipped with a very good APF for reading CW signals in the noise. Antennas are a 2*11 meter long doublet at an average height of 6 meters, using an open line feeder and auto tuner CG3000.

Two orthogonal small broadband active receiving loops and two phase coherent SDR receivers are used for one mouse click noise cancelling, stereo diversity noise reduction and for measuring propagation polarization behavior over frequency.

I am now (Dec. 1 2018) retired as a mixed signal electronic developer/engineer from Océ - A Canon Company.


The information on my internet site is a result of the ever increasing level of man-made noise on the HF bands.

May be the noise level is inversely proportional to the level of civilization? Any noise: acoustic, electromagnetic or light.



There are five sections:


1) Analog section

Some examples of what can be found on this route

- dual loop antenna system

- broadband small loop amplification update Dec. 2018

- broadband small loop amplifier update Dec. 2018 of 2003 design

- noise canceller / phaser update March 2019 of 2006 design


2) Digital Signal Processing section (QEX 2006)

Some examples of what can be found on this route

- effective directivity by DSP

- two phase coherent Software Defined Radio’s (two Elecraft K2 receivers as SDR)

- ideal phaser/noise canceller in DSP (e.g. for phased array’s)

Some audio samples:

- enhanced stereo reception by DSP

- CW filter optimized for weak signal reception


3) Finding Signals in the Noise using two Antennas section (QEX 2019) added Febr. 2019

            - One mouse click Noise Cancelling

            - Stereo Diversity Noise Reduction

            - Measuring propagation polarization behavior over frequency

            - GNU Radio implementation of Noise Cancelling (added April 2019)


4) XO Mode Propagation section



5) NoiseLesser: noise reduction software section

Last NoiseLesser update June 2015






Link to my published ham radio articles


73 es cu on the band,


(I do only paper QSL)


Contact: PA0SIM








Permission is granted to use the information and the software on this website for private, non-commercial use only. If you use the information and the software provided by my pages for non-commercial use, please make reference to the source of the information.

Using the information and the software provided by my pages for commercial use is only allowed after my explicit and personal permission.

I will not accept responsibility for any damage to your equipment through the use of this information and the software or as a result thereof.



Last update: May 24, 2019