“Today I found the source of a large RF noise on 20 and 40 meter band!”
On the next frequencies (14.151, 14.215, 14.274, 14.333, 14.396 and 7.098, 7080, 7.035 and 21.113, 21.172, 21.297) i heard a large spike signal. A signal with an ‘step over frequency’ (harmonic) of 60 kHz. The signal was so strong that on the ham-band I couldn’t work anymore.
I had switched of all the UTP network and cisco switches.
The noise was gone !
By switching on, one by one .. it seems that the main bad source was linksys IP
SIP phone SPA942 and the Cisco 1 Gb switch SD2005.
The basic idea I found on the website from ehamforum (scroll to the bottom of the
forum .. )
Now I have to find out (or change the hardware =;) to reduce the RF noise on this hardware.