[Elecraft] [K2] LPF tuning for 20m

[Don Wilhelm]

Chip,

Yes, the lack of smooth tuning indicates a faulty C23.
You might try spinning the rotor around through 10 or 12 times and see 
if that helps.  There may some dirt of corrosion on the rotor wiper contact.

The power after a band change or a power level change normally starts 
out low and builds to the requested power after a couple dit times - 
that happens on all bands, but if you do not have good tuning of the 20 
meter BPF, it may be more noticable than normal and take longer to come 
up to full power.

73,
Don W3FPR

On 4/13/2015 12:46 PM, Chip Stratton wrote:
> Hi Don et al -
>
> I'm tuning up a K2 recently acquired from an estate. On transmit, tuning
> C23 seems to be an on/off valve. On either side of a broad middle range
> power output is very low, about 300 mW. The transition to a full 10 watts
> or so is very sudden. Continued rotation it stays cons tant at that level
> until an instantaneous drop back down to the 300 mW level or so.
>
> Does this lack of a smoother change imply a problem with C23?
>
> I have occasionally noted that even after having carefully tuned this LPF
> that 20m CW power starts very low. After switching to another band and back
> it usually normalizes. This even transmitting into a 50 ohm dummy load.
> Seems it could be related to C23 behavior?
>
>