On 12/31/2017 10:58 PM, [email protected] wrote:
> The actual passband of these two filters is more important than the
> marketing name.
The "marketing name" on the <Inrad> filters is effectively the -1dB
bandwidth. The name is derived from their original use in Yaesu rigs
and Yaesu's marketing where there were two filters in cascade and
represents the final effective bandwidth of the cascaded pair. Plot
the cascaded bandwidth of the Inrad #701/#703 pair (400 Hz), #708/#704
pair (250 Hz) or the #711/#714 pair (1800 Hz) and see how that works.
When one has only the first IF filter, the "cascade" is provided by
the 2nd IF DSP. In the K3/K3S what does the "WIDTH" display actually
show - the -0dB, -1dB, or -3dB point of the 2nd IF response? Then,
how does that match with the first IF filter and what is the composite
response.
73,
... Joe, W4TV
On 12/31/2017 10:58 PM, [email protected] wrote:
The actual passband of these two filters is more important than the
marketing name. The "400 Hz" filter is about 435 Hz wide at the -6dB
points. The "250 Hz" filter is about 380 Hz wide. Look at the graphs on
the Elecraft website.
Ed W0YK
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of [email protected]
Sent: Sunday, December 31, 2017 7:32 PM
To: 'Elecraft Reflector' <[email protected]>
Subject: [Elecraft] filters
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
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