[Elecraft] K3 Roofing Filter Gain Setup

[drewko]

If I use a 50uv signal generator to set the filter gains for equal
readings on my K3's AFV meter I arrive at the following compensations:

2.70 KHz = 0db
500 Hz = 4 db
250 Hz = 8 db

This is way more aggressive than the suggested amounts but these
figures do sound equalized to my ears for real signal conditions. The
factory settings are noticeably weak. Maybe my particular filters are
just not up to par.

73,
Drew
AF2Z


On Sat, 28 May 2011 14:18:45 -0700, you wrote:

>There are recommendations in the K3 Owner's manual (see "Crystal Filter
>Setup", indexed, on page 46) :
>
>Use VFO A to set the gain in dB. In general, you'll want to add 1-2 dB for
>400-500 Hz filters, and 3-4 dB for 200-250 Hz filters. 
>
>and there is a table (with essentially the same guidance) in K3 Utility Help
>for the Filter Configuration page. I've lost the table formatting in
>cut/paste from Help, but here's the information:
>
>Narrow crystal filters tend to have more passband loss than wide filters.
>You can compensate for this effect by specifying an amount of added gain to
>use for each filter in receive mode. Enter the desired gain "boost", in
>decibels, for each filter. You may specify a value between 0 and 8 dB. 
>
>Elecraft recommends using the initial loss compensation values below. You
>may wish to further adjust the values for your particular filters. 
>
>Part Number Bandwidth Gain 
>
>KFL3A-200 0.20 kHz 3-4 dB 
>KFL3A-250 0.25 kHz 3-4 dB 
>KFL3A-400 0.40 kHz 1-2 dB 
>KFL3A-500 0.50 kHz 1-2 dB 
>KFL3A-1.0K 1.00 kHz 0 dB 
>KFL3A-1.8K 1.80 kHz 0 dB 
>KFL3A-2.1K 2.10 kHz 0 dB 
>KFL3A-2.7K 2.70 kHz 0 dB 
>KFL3A-2.8K 2.80 kHz 0 dB 
>KFL3A-6K 6.00 kHz 0 dB 
>KFL3B-FM 13.00 kHz 0 dB
>
>73 de Dick, K6KR
>
>