Posted by
wayne burdick on
Feb 16, 2019; 10:56pm
URL: http://elecraft.85.s1.nabble.com/Searching-for-Noise-i-e-Samples-Thereof-tp7648980.html
As time permits, we're trying to better characterize the RF noise that plagues stations at various locations.
So far, data collected during this informal survey has taken the form of verbal descriptions. Scope traces or digitized samples would be much more helpful, since they'd show the actual waveforms. We could then look at how to better suppress the noise profiles, pulse widths, and rep rates encountered by stations surrounded by modern appliances, vehicles, peripherals, lighting, etc. Many of these didn't exist decades ago when the first noise blankers were designed.
On a K3 or K3S, the best place to capture noise signals would be at the output of the first MC1350 in the KNB3's amplifier chain. In the presence of strong noise, the signal at this point is likely to produce a visible scope trace, or a good sample using an RF digitizer. The latter would have to do a good job at the IF, 8.215 MHz.
On a KX3, the RX IQ outputs should work, assuming the noise signal is quite strong. As the RX IQ signal occurs at base band, a much lower-bandwidth scope or an audio-class A-to-D converter would suffice.
Spectral data would also be of use in both cases.
I don't have any specific recommendations for equipment or software. But if you have the means in hand, as well as a noise problem worth capturing, feel free to contact me directly. Please include photos or screen captures as well as details on what remediation techniques work -- and don't.
73,
Wayne
N6KR
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