[Elecraft] K3 Filter Option Questions (revisited yet again)

[Dick Dievendorff]

Phil:

I'm also primarily a CW operator. I chose the 1 KHz filter for "normal" wide
CW contest use when I want to be aware of stations around my run frequency.
I chose a 1.8 KHz filter for SSB contesting based on recommendations from
friends whose opinions I respect. The 1.8 kHz filter is also helpful for
wide CW. 

I also have the 400 Hz and 250 Hz eight pole filters.  I don't think the 400
and 250 are enough different to recommend that configuration.  If you're an
RTTY enthusiast, the 250 Hz filter may be just what you need.  Upon
reflection, I perhaps should have gotten the 200 Hz 5-pole instead of the
250 Hz 8-pole. I ordered this on the first announcement at Visalia, and went
with my best guesses.

I chose the 2.8 kHz filters for steep skirts and also to avoid matching
issues with the sub receiver's filter.  I'm not sure they were necessary,
but it's all subjective. I didn't want to be in mid-contest and wish then
that I'd spent a relatively few dollars more for better skirt selectivity. 

One reason to choose the 2.8 8-pole over the 2.7 five-pole is if you plan on
using a sub receiver. You should either match the 2.7 kHz five-pole filters
or get two 2.8 kHz filters. I chose the latter.

I don't require ESSB, AM transmit, or FM, and my main RF board is full with
250, 400, 1000, 1800, and 2800 eight-pole filters. I have fewer filters on
my sub receiver.

Also review Eric's detailed Roofing Filters essay at
http://www.elecraft.com/K3/Roofing_Filters.htm

Nice to have the choices, but there are a lot of them!

73 de Dick, K6KR


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Phil Hystad
Sent: Wednesday, December 23, 2009 11:41 AM
To: Elecraft Reflector
Subject: [Elecraft] K3 Filter Option Questions (revisited yet again)

One of the things that I have not yet decided is the filters to get for my
K3 order.  I am firm on getting the 400 Hz 8-pole filter (80 percent or so
CW ops).  But, I like to scan the band looking for signals with a wider
filter, say around 1 to 1.2 KHz.  Do I need to get the 1 K filter.  If I
remember right, I can set DSP filtering to about 1 KHz which may be good
enough or is there an advantage to the 1 KHz filter.

Also, is there a good reason to swap out the 5-pole 2.7 kHz filter for the
2.8 KHz 8-pole?  I presume this gives the filter sharper skirts so you can
cut off those close stations a bit better but I am curious as to how much
better.

Since the dollar cost differences in decisions regarding filters is not that
great I would prefer answers that ignore the cost issue.

So far, I am planning on getting the following filters with a ? on the 1 KHz
8-pole and 2.8 KHz 8-pole:

400 KHz 8-pole
1 KHz 8-pole  ??
2.8 KHz 8-pole swap for 2.7 KHz 5-pole ??
6.0 KHz 8-pole

73,
phil, K7PEH
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