[Elecraft] What's happening here?

[Sverre Holm]

> When I tune my K2 on 160m from 1822.66 to 1822.65, I hear a 
> popping sound and the S meter shows a spike of about S2.  
> When tuning the other direction, there is no pop when I go 
> from 1822.65 to 1822.66.  I've not noticed this on any other band.

It is probably a quite normal thing which also happens on all the other
bands. 

The K2 PLL is driven from a reference oscillator on nominally 12.088
MHz. The PLL can generate a certain set of frequencies from a fixed
12.088 MHz frequency, but to get the fine steps the reference oscillator
has to be pulled over something like 12.08 - 12.1 MHz. That's why there
are varicaps around this crystal. As the oscillator gets to the end of
the pulling range, say 12.1 MHz, and you want to increase frequency even
more, it will instead move to the lower end (~12.08) and change the
division factor in the PLL. This can create the pop.


--
73, 
Sverre

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Sverre Holm, LA3ZA
www.qsl.net/la3za