[Elecraft] 2.8 kHz filter tilt

[David Gilbert]

I sometimes marvel at the number of different directions Elecraft gets 
pulled with respect to the K3.  I can't imagine two more polar opposite 
message threads than this one and the recent ones discussing AGC 
action.  I'm not trying to overtly judge the merits of either camp, but 
one is trying to optimize the rig as an audiophile piece of equipment by 
eliminating 4db of passband tilt on single strong signals in a 
conversational setting and the other is trying to optimize its 
communication capabilities by eliminating IMD mush on multiple low level 
signals in a contest setting.

Hopefully for the sake of Wayne, Eric, Lyle and company schizophrenia is 
not an acquired disease ...

73,
Dave   AB7E




On 12/12/2010 3:18 PM, ab2tc wrote:
> Hi again,
>
> A little while ago I wrote the message below. I am still searching for ways
> to compensate for the tilt in my new 2.8kHz crystal filter. One way would be
> to have a way to set the RX equalizer through a serial command / macro. Is
> this going to happen soon? Another way would be to have the RX equalizer
> settings stored by mode so they could be different for USB and LSB. Is this
> going to happen soon? Am I really asking too much here? I spent money
> getting the 8 pole 2.8kHz filter hoping it would solve the tonality
> difference between USB and LSB, but achieved nothing. Recently there was
> somebody on here wishing that Elecraft would sort these filters weeding out
> the ones with a bad tilt. Should I order another one hoping to get one with
> a flatter response?
>
> AB2TC - Knut
>
> Hello all,
>
> I recently replaced the 5-pole 2.7kHz roofing filter in my K3 with the
> 8-pole 2.8kHz hoping to get rid of the difference in tonality between USB
> and LSB. But the difference is still there. These two links show the noise
> spectrum of the receiver in USB and LSB.
>
> http://ab2tc.getmyip.com:8000/pictures/usb.png
> http://ab2tc.getmyip.com:8000/pictures/lsb.png
>
> In USB there is a definite upward tilt of the passband and the opposite for
> LSB. This is quite audible. Is this normal and is there anything I can do
> about it (other than asking Elecraft to add by mode equalizer)?
>
> AB2TC - Knut
>