[Elecraft] [Bulk] 8 or5 Pole cw filters

[Bill Coleman]

> On Jan 14, 2015, at 3:21 AM, Guy Olinger K2AV <k2av.guy at gmail.com> wrote:
> 
> I would note that in crowded contesting conditions, you pretty much
> have to use a filter which matches the DSP setting. What gets by the
> roofing filter can engage the "defensive" hardware AGC which is there
> to keep input to the analog to digital conversion in the sweet range
> of the AD device. This can become a problem with very loud signals
> right at the edge of the DSP passband, if the roofing filter is not
> close in bandwidth.

I disagree with this assessment. The DSP filtering is quite good. You only have a problem with a wider roofing filter causing the hardware AGC pumping for extremely strong signals that happen to be within the bounds of the roofing filter, but outside the DSP filter. Unless the roofing filter is really wide (like using the 2.7 kHz filter in a CW contest) this doesn’t happen that often.

I find the stock 2.7 kHz roofing filter more than adequate for SSB contesting, and the 500 Hz roofing filter perfect for CW and RTTY contesting. 

The K3 is a fantastic radio even if you don’t have a bunch of really expensive crystal filters….

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Web: http://boringhamradiopart.blogspot.com
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901