[Elecraft] K3 Passband/DSP Filter Display Question ?

[Phil Hystad]

I have had my K3 for four years but rarely make use of the passband tuning features.  Today though I was experimenting with APF and the passband controls and learned that I really do not know what I am doing.

In particular, the VFO B display is a mystery to me during passband tuning and APF SHIFT tuning.  For example, in passband tuning (APF not enabled), the VFO B display says FC and then a number like 0.70 or whatever.  What does "FC" mean (I can guess, but that would not be useful) and what is this number.  I scanned all the documents I have and have not found descriptions of the content of the VFO B readout during passband tuning.  I know it has something to do with shifting the frequency of center (I think) so maybe FC means Frequency Center.  Also, there is an asterisk in the field, like:  FC  *0.68.  Maybe someone can interpret the meaning of that.

If I knew the definition for passband tuning for the VFO B field content I could probably guess at the meaning of the APF enabled display which is similar such as:  APF  *0.68.

I have found lots of description of passband tuning and that part of the display showing the passband width and position but nothing describing the VFO B contents (not covered in documentation on alternate VFO B displays either).

73, phil, K7PEH