[Elecraft] K3 Received Signal Drops When Roofing Filter Switched In

[Vic Rosenthal 4X6GP/K2VCO]

I used the dBV function to match the filter gains so that there would be 
no difference when switching filters. In my case I found it necessary to 
set the 400 Hz filter gain to +5 dB. You can do it by ear, but either 
way you need a steady signal. I used my little Elecraft XG1 to generate 
a steady 1 uv signal.

Note that if you have the subreceiver, filter gains may need to be 
different. The easiest way to set them is with the K3 utility.

Regarding the RX EQ, I don't use it at all on CW, because at narrow 
bandwidths the pitches that you hear are determined by the width and 
shift. If you like to listen to CW with 2 kHz bandwidth, then it might 
be useful, but I don't.

You absolutely should NOT set the RX EQ to boost any frequencies on CW. 
Just cut the ones you don't want. This is because the RX EQ is turned 
off at bandwidths < 150 Hz. As a result, if you are boosting 400 Hz by 2 
dB, then when you go to a narrow bandwidth the boost disappears -- 
exactly what you don't want!

73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/

On 22 Oct 2015 03:13, engineercm wrote:
> Thanks to all that pointed me to the filter gain settings accessible with the
> Utility.  It was set at 2 db which is the recommended value in the K3
> manual.  Now that I know where the parameter is, I'll experiment more with
> weak signals.  The manual does not suggest going above 2 db claiming DSP
> operation would be impaired in some way.
>
> I've also concluded that the sharp drop in noise when the filter kicks in is
> to be expected.  I found the same instantaneous drop in noise with the 200
> Hz filter is engaged.  Not at all annoying; I was just trying to understand
> this marvelous radio.
>
> I'm primarily a CW op and will leave the Rx Eq set at +2db around the
> sidetone frequencies and all others -10 or better.  That seems to suit my
> ears and my current operating skill.
>
> 73 de Clark WU4B
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K3-Received-Signal-Drops-When-Roofing-Filter-Switched-In-tp7609366p7609423.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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