Posted by
Don Wilhelm-4 on
Feb 18, 2010; 12:15am
URL: http://elecraft.85.s1.nabble.com/My-Five-Filters-tp4586377p4589291.html
Phil,
Don't get so stressed. My K3 has 3 open filter slots, and it does not
concern me at all.
How much serious contesting do you do - how much serious DX Chasing?
Consider my logic: The DSP filtering alone is really good and will
handle conditions under more casual situations than the above. Just
dial in the filtering you want.
The "rub" comes in when there are a lot of strong signals in the Roofing
filter passband. You may not hear them with the DSP filtering tightened
up, but they will activate the hardware AGC and will de-sense the
receiver. The reality of that happening are not usually present in
normal operating, but will be present in serious contest and DX Chasing
situations.
My opinions:
1) A wide CW roofing filter is of little value. There will be so many
signals in the passband that at least one is likely to activate the
hardware AGC, so I figure that the normal 2.7/2.8 kHz filter with DSP
set somewhere between 700 and 1000 Hz width will be about as good as the
1000 Hz filter.
2) If you are a SSB contester, go for the 1.8 filter (or even the 1.5
from Inrad) if you want to operate in extreme SSB conditions.
3) For CW contesting and DX Chasing, you will likely want a roofer in
the 400 Hz or even 250 Hz range - which one depends on how much you are
willing to dig for reception under crowded conditions. As the filter
gets more narrow, the more critical (i.e. slowly) one must tune, or the
desired signal will suddenly disappear outside the passband.
4) For Data modes where one tunes with the VFO rather than clicking on a
waterfall display, a 400 Hz filter is a good thing to have - some would
argue that a filter in the 200 to 300 Hz range would be better, and that
is logical too - which depends on how critical you wish to tune and how
important that elusive contact is to you.
OK, I have not said which filters to use, but for me, the ideal set
would be 13 kHz (discard if you don't want to do FM), the 6 kHz filter
if you want to transmit AM or ESSB (the 6 kHz is good for SWLing,
although the 13 kHz will do fine for that too). The 2.7 or 2.8 kHz
filter is required. Then the 1.8 (alternately the 1.5) for SSB
contesting/DXing. The 400 Hz filter for normal CW, although for general
tuning I like 700 Hz - do that with the 2.7, 1.8, or 1.5 kHz filter and
the narrowed DSP filter. For extreme CW or data mode work, any roofing
filter in the 200 to 300 Hz range will do for me.
That fills the slots - 13 kHz, 6 kHz, 2.7/2.8, 1.8/1.5 and 400/200-300
range. If you do not want FM, then you will have 1 empty slot.
OK, that is the ideal for me, and I am building on it - I currently have
the 13 kHz and the 2.7 kHz filters installed. Right now, I am not
interested in serious DXing or contesting, so until that bug bites me,
the other slots will remain empty.
Those are my thoughts and the reasons I have chosen this path - YMMV,
make up your own criteria based on your operating desires.
73,
Don W3FPR
Phil Hystad wrote:
> Each morning I wake up stressed because I do not have all five filter slots populated. There is a hole in my K3 and it bothers me. I had been saving the high end for a FM filter but now decided that "No, I won't be doing FM with my K3". So, my filters are: 400 Hz, 1000 Hz, 2.7 KHz (5-p), 6 KHz.
>
> I am thinking of adding another filter and I am thinking of the 250 Hz because I prefer CW over SSB and I think I would get more use out of that end of my filter lineup.
>
> So, is it overkill to have the 250 Hz and the 400 Hz filters in the same K3?
>
>
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