[Elecraft] KXB30 sensitivity better than KXB3080?

[Don Wilhelm]

Martin,

Yes, peak the trimmers on 30 meters - use a fully insulated tool (like a 
ceramic or hard plastic screwdriver) for the most precise tuning.  If 
there is anything metallic on the screwdriver, your hand capacity will 
have an effect while tuning.  If you only have a metallic tool, wrap the 
shaft with tape and tune a little at a time and try with each trial 
until it seems to be at the optimum setting.

The 30 meter trimmers are not in the active part of the circuit on 80.  
The 80 meter receiver front end  tuning is broad and the capacitors that 
tune it down to 80 are fixed 300 pf caps.

73,
Don W3FPR

Martin (VA3SIE) wrote:
> Hi, Don.
>
> Well I finally did get around to checking out the KX1 with a signal generator.
>
> Here are the signal levels at which I can barely distinguish a signal:
>
> 80m -126dBm
> 40m -130dBm
> 30m -107dBm
> 20m -120dBm
>
> So, 30m does appear to have a problem.
>
> I'll have to try re-tweaking the 30m trimmers, but it's interesting
> that 80m has much better sensitivity than 30m.  The KXB3080 manual
> indicates that peaking the 30m trimmers affects 80m as well, so you'd
> think that if 30m was poor 80m ought to be poor as well.
>
> The KXB3080 manual indicates that on 30m,  C3 and C4 come into play.
> I'm unclear if on 80m C1 and C4 remain in play, or if they are
> replaced by C2 and C5 (ie. are there any trimmer capacitors in play on
> 80m?)  If both trimmers are out of play on 80m that would certainly
> indicate that I simply need to find a non-metallic screw-driver and
> peak the caps.  If however the trimmers remain in play on 80m, and my
> 80m performance is pretty good, then perhaps either or both trimmer
> caps are defective.
>
> Anyway, next step is re-tweaking those caps!
>
> Thanks,
> Martin.
> VA3SIE.
>   
>