[Elecraft] [K3] Perfect for Field Day S&P ... Limited Production 700 Hz 8-Pole Filters

[Ethan Miller K8GU]

Like Don, I have the 700-Hz filter and would never have heard of it
without Gary's announcements on the list.  Considering some the other
dubious stuff that gets posted on the list, I'm happy to hear about
things that are actually of interest to me.  It's not magical, but
when I found myself opening up the DSP bandwidth beyond 400 Hz to
600-800 Hz a lot of the time while working/listening to pileups,
quickly tuning a band, or operating casually, I thought it a good idea
to invest in one.  It's been worthwhile for me...

Personally, I would think it is of limited utility at Field Day versus
the 400 or 250/200...trashy rigs (and AKTR operators) notwithstanding.

73,

--Ethan, K8GU/3.

K3/100 #6714
K2/100 #7372
TS-930S #5010245


On Sun, Mar 2, 2014 at 3:05 AM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
> Fred,
>
> Everything you say is true, the DSP does set the final filter width, but the
> hardware AGC can cause pumping in the presence of nearby strong signals.
> Since my normal desired CW tuning width is in the vicinity of 700 Hz, I
> bought and installed one of the 700 Hz filters.  YMMV some say that a 1000
> kHz roofer is fine, and others say that the 2.7 kHz filter works just fine
> too, but I am satisfied with the 700 Hz width - that is a personal
> preference, I am not here to convince others about my choices, but only to
> give information that will allow others to make intelligent choices that
> suit their needs and desires.
>
> 73,
> Don W3FPR
>
> On 3/1/2014 7:59 PM, Fred Jensen wrote:
>>
>> If you can, help me out here Don ...
>>
>> These are roofing filters.  From my perspective, which is likely wrong,
>> their job is to restrict the bandwidth presented to the 2nd mixer [and
>> downstream ADC].  They are of most value when you have very strong [i.e.
>> geographically close] signals adjacent to the desired signal [That would be
>> WX6V for me :-)].  The ultimate BW is set by the DSP of course, but a really
>> strong adjacent signal can begin to activate the HW AGC in the K3 which
>> affects the signal inside your DSP BW, or I think that's true. So, it
>> follows to me that, if you are plagued by KW neighbors, narrower roofing
>> filters can reduce that problem.  This could be true on FD or any other
>> closely spaced HF operations ... IF you have two stations on the same
>> band/mode.
>>
>> If you are not so plagued, I can't figure out why it really matters.  I
>> have the filter that came with the K3 and I bought one [2.7 and .5, I don't
>> remember which was which], I've had no difficulties.  Jim [WX6V] and Jack
>> KF6T [equally close] became non-problems when I got my K3 ... even more so
>> now that Jim has a K3 and phase-noise has disappeared. :-)
>>
>
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