Clark wrote:
> ... when changing between the three filters the width of the plot
> varied very little. I would have expected to see a vastly different
> shape between the 800 Hz filter and the 250 Hz filter.
>
> So, do I need to take the "screws" out anyway?
I'm sorry, OM, but this is the K3 list! :-)
Seriously, though, I don't know what you could adjust. The bandwidth is controlled by altering the bias voltage on the variactor diodes associated with the four-pole IF crystal filter network, which is done by the front panel MPU in response to operator input.
Do you experience a noticable bandwidth reduction as you select the narrower filter settings in normal operation? That effect is very obvious on my K1, as determined by the elimination of nearby signals as I choose the narrower settings. The narrow settings are very effective!
I've never used Spectrogram...it seems like overkill for the K1, and it is not called for in the "official" alignment instructions. In fact, it has occasionally caused problems for people who used it to align precisely the receiver, and then made the (wrong) assumption that they shouldn't have to readjust the alignment of the same caps/coils for the transmitter. But alignment of the filter board for transmit is far more critical than the alignment for receive. But none of this has anything to do with what you are talking about.
73,
Mike / KK5F
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