Hi Adnan, > Okay the things is that I am using the sound-card and not the USB port > to input my data from the sdr mixer. The problem I have is that how do > I isolate my hardware device(sdr receiver) from noise generated by the > PC (i think because of the many oscillators that a PC has). The > problem is that the issue is not that the noise will enter in the > interfacing portion. But that it will directly affect my SDR > reception. Are there any good tips and techniques on how to make your > PC electromagnetically silent(so that it does not radiate its own > frequencies). It depends on frequencies and distances.
On HF I would suggest that you simply move the antenna a bit further away from the PC. First try with a dummy load at the antenna input. Then you should not pick up any noise from the PC. If you do, adequate shielding and decoupling of the HF parts of your radio hardware should solve the problem. Then use a coaxial cable to the antenna. Make sure currents will not flow on the outer conducter with traps. You may wind a couple of turns and tune with a capacitor so the outside of the screen forms an LC resonator. Place at least three such resonators 0.25 wl from each other along the coax and place the antenna ay least 1 wavelength from the PC. Use a proper balun at the antenna. Instead of traps, use ferrite cores and no tuning capacitor if you want wideband isolation. At higher frequencies where the PC actually radiates (although mainly from wires connected to it) you might need a more elaborate solution: http://www.sm5bsz.com/linuxdsp/hware/quietpc.htm 73 Leif / SM5BSZ > > For those of you who want to see the affect do this: > 1- shut down your pc and listen to any ordinary radio that you have > availabe > 2- no switch on the pc and "try" to listen to the radio. Just observe > how the performance falls. > > yours truly, > adnan yusuf > > > > > Yahoo! Groups Links > > >
