I use similar settings for CW, with both filters. I haven't tried DSP
bandwidth of 250 Hz with the 400 Hz crystal filter, but based on the
filter characteristics, I don't think it would make much difference.
Also, the 250 Hz filter drifts around so much with temperature that it's
hard to keep it centered properly.
Compare the responses here:
http://www.elecraft.com/K3/K3_filter_plots.htm
Anyhow, all I'm saying is that even for a pretty hard-core CW contester,
I'm not sure the narrow filter is worth the investment.
Now, my previous rig, an FT-1000D, which is inferior to the K3 in almost
every other way, actually has better skirt rejection on CW, but that's
with cascaded crystal filters, both of either 500 or 250 Hz bandwidth.
I'm not sure that's because of an inherent limitation of the K3 DSP, or
just the filter algorithm chosen (perhaps to limit latency?).
73,
Scott K9MA
On 12/31/2017 21:32, [email protected] wrote:
400Hz is definitely my favorite CW and RTTY filter. I also use the 250Hz
roofing filter (switched in at 350Hz) when the QRM gets bad, what document
shows that this offers little improvement?
John KK9A
K9MA wrote:
Assuming it's for a K3(s), I don't think you will find the 250 Hz filter
very useful. The response that both Elecraft and I measured shows that
the narrow filter really isn't much better. Were I to do it again, I
would only use the 400 Hz ones.
73,
Scott K9MA
On 12/31/2017 17:02, doug dietz wrote:
Guys
i ordered a 400hz filter by mistake. I have use for a 200h or 1k, 18.k
What ya got
doug49707 at gmail.com Doug WD8Z
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
--
Scott K9MA
[email protected]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
