FLx GN at Maximum

[Barry Pfeil]

Is it unusual or does it cause any problem to have a filter gain setting at it's max value?  Is that gain occurring in the IF DSP or elsewhere?  Following the procedure below I ended up with the gain for my 400 Hz roofing filter set at the maximum 8 dB setting.

 

I used the Elecraft XG1 (set at 50 microvolts output level) direct into the K3 (sn 1774) which was in CW mode and set initially to the 7040 kHz nominal frequency of the XG1.  I then used the CWT and SPOT controls to tune more accurately, showing the oscillator to be about a 0.1 kHz low.  At the stock 2.7 kHz roofing filter width the AFV indicated 1248.  With the 1.8 kHz roofer it showed 1275 and initially the 400 Hz filter showed around 1130(?) with the FL3 GN set at 2 dB per the "typical" mentioned in the manual.  But using the AFV indicator, I ended up increasing the FL3 GN to 8 dB, it's maximum setting.  This brought the AFV indication for the 400 Hz filter up to 1250.  Switching between the filters and just listening, the signal levels do sound exactly the same.

 

In the analog world, I'm sometimes concerned about "calibration" controls set at their extremes but maybe it is an non-issue here?

Thanks, Barry, K6RM

 

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[KK7P]

> Following the procedure below I ended up with the gain for my 400 Hz
> roofing filter set at the maximum 8 dB setting.

There are nominal variations in the various filters.  My 400 Hz filters
happen to need a gain of 4 (sub) or 5 (main) dB.  My 250 Hz filter
(main) needs 7 while my 200 Hz filter (sub) needs 3 dB.

The limit of 8 dB is software enforced.  The DSP can apply significantly
more compensation if necessary.

73,

Lyle KK7P
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