[Elecraft] Musings on Noise Reduction

[John Graf]

I ran a single-op QRP effort in the ARRL 160M contest this weekend.  I ran
about half the time with my K2, and the other half with my K3 @ 5 watts.  It
was interesting to compare the two rigs.

I did not run any laboratory tests, so this clearly falls into the category
of opinion.  But the K2 DSP noise reduction is far superior to the K3's, at
least on 160M.

I played with the settings on the K3's NR throughout the contest, but it
always appears to me that engaging NR reduces the signal level by a good 10
dB (or more) no matter what you do.  By setting it to F1-1, there is a
reasonable tradeoff between noise reduction and signal strength, but just
about any other setting seems to drop the signals into the mud,

I also did some reading (during daylight hours) and found a good article on
K3 NR at http://www.zerobeat.net/mediawiki/index.php/K3_DSP  The gist of
that article is that in order to get the most benefit from the NR system,
you need to keep your bandwidth set rather wide.  There may be some truth to
that. but it is not a strategy that works well during a contest.

The K2, on the other hand, does not significantly reduce signal level when
NR is engaged.  It also does a great job of dropping the noise level by
several S-units.  There is some signal distortion, but it is not
objectionable.  The best part is that you can reduce the bandwidth using the
narrower CW filters, and the noise reduction is not affected.

The K3 is a superior rig in most aspects and is still my choice for
contesting in LP and HP categories, as well as for DXing.  But so far I have
not been enamored with the noise reduction system.

Thanks and 73,

John, WA6L


-- 

Joe E. Lewis  - "The way taxes are, you might as well marry for love."
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