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

[Fred Jensen]

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. :-)

I've got to be missing something here, and sadly, it wouldn't be even 
close to the first time.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org


On 3/1/2014 4:03 PM, Don Wilhelm wrote:
> Eric has permitted such announcements, but limits them to one a month.
> You will see offers to build a K2 that come in that same category.
>
> Personal comment -- I particularly like the 700 Hz CW filter in my K3. I
> got used to tuning the bands using a 700 Hz filter width in my K2, and
> opted for the 700 Hz roofing filter when it was offered. Yes, I find it
> nice for 'scouring the pileup' before switching to the narrower 400 Hz
> filter when listening to a pileup.  YMMV, but it is an available option.