[Elecraft] K3 Roofing filters

[Matt Zilmer]

Hi Ivan,

250 Hz:  CW and some data modes
1.8 KHz: Other data modes (MT63, WL2K) and SSB Narrow
2.8 KHz:  Normal SSB
6.0 KHz: SWL (AM and DSB) and 80m AM nets
15.0 KHz: FM on 10m and 6m

The 250 Hz roofing filter works extremely well in crowded band
conditions on CW.  It's also just about right for low-bandwidth data
modes like PSK, Thor, Olivia, etc.

If you only need two, I'd go with 250 Hz and 2.8 KHz.  Both are
8-pole.  I say this because your main interest is in CW, and either
the 2.7 or 2.8 KHz filter is needed no matter what.

I've had both 5- and 8-pole filters.  The skirts are somewhat steeper
with the 8-pole, but both types perform quite well.  Just remember
that the DSP provides most of the filtering you'll hear.  The roofiing
filters reduce (or in many cases, eliminate)  close-in blocking from
adjacent interference.  Very handy in crowded contest conditions.

73,
matt W6NIA

On Tue, 06 Aug 2013 10:37:27 +0100 (BST), you wrote:

>I am about to purchase a K3 (k). My main interest is certainly CW with occasional
 forays into SSB and even data, and I note the selection of roofing
filters available, no doubt the 8-pole are somewhat better but what is
the general feeling regarding the bandwidth(s)  to be included.
>Ivan G3IZD
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