[linrad] Quietening computer noise

[Richard Hosking <richardh@xxxxxxxxxxxxxxxx]

Dear all
I have managed to recieve signals on HF using two SBL-1 mixers driven by 
a quadrature LO (AD9854) and a couple of low noise opamps (NE5534). 
Linrad runs in direct conversion I/Q mode. The main limiting factor at 
present is noise from both computer and monitor.
The sound card is bog standard and the machine is a PII 400 MHz running 
RH9, but with only 64MB of RAM

Questions
The max filter bandwidth appears to be about 2 KHz on SSB, and narrower 
on AM  - if I try to make it wider nothing happens.
Is this due to RAM and processor limitations?

How to get rid of that computer noise? ( I have made no attempt whatever 
so far)

Thanks in advance

Richard




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