Welcome to PA0SIM´s home page


Dedicated to Ham Radio


[Analog route]

[Digital Signal Processing route]

[Published Articles] [Ordinary and Extraordinary Mode Propagation]


My main interest is CW on short-wave, but thanks to the companies that don’t know how to design for EMC, my next interest is reducing QRM.

So you will find on these pages mainly my ideas, experiences and results on local and non-local QRM/noise reduction.


The three main routes are: the Analog route, the Digital Signal Processing route (DSP route) and the XO Mode Propagation route.


Some examples of what can be found on this site:

- small active receiving loops

- dual loop antenna system

- phaser / noise canceller

- effective directivity by DSP (phasing and muting)

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

- ideal phaser in DSP

- etc.


Some audio samples:

- enhanced stereo reception by DSP

- SSB and CW Noise Reduction

- CW filter optimized for weak signal reception

- etc.


Free software:

If you do not like noise and/or you think your IC-7700 has good noise reduction, you should try the highly effective audio noise reduction software (.ZIP file) available at the end of the Software page (last update: August, 2014).

This 40mtr SSB_example gives an impression of the noise reduction.

For CW I have the following 20mtr samples: CW_unprocessed, CW_nLMS_NR, CW_FFT_NR.


I don’t have a lot of acres for antennas. Having a small city lot and too many neighbours makes the chance of local QRM very real. Not all sources can be tackled and you have to live with these remaining sources.

You have neighbours and no local QRM? Then you are (still) very lucky.


By the way:

The level of civilization is inversely proportional to the noise level (any noise: acoustic, electromagnetic or light).

Maybe that's why SETI has heard nothing yet.




View of my shack over 360°. Photographer: Wil Brugman.

Using Pixaround (PixScreen Lite) gives the best results.

Other links




73 de Jan


(email PA0SIM) (mycall is PA0SIM)


(email PA0SIM)


(email 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: August 10, 2014