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Hi Adrian, Lun, Jim & Paul,

I'm fascinated by your efforts to optimize the sweeps, however, I wonder, whether this will really have a recognizable effect in day-to-day operation.

From what I got now - after having looked at quite some messages with the sweeps - my QMX seems to me more or less an unoptimised average. -? I'm pretty much there, where Adrian was before adding the cap. Here we go:

I'll recheck again after the diode Mod from Hans ... But If nothing worsens, I'm not so sure, whether it will be really worth trying to tweak this to the end.

Do you have any practical tests apart from the sweep, that suggest a significant improved performance?

Vy73

Stefan.

Hello Paul,

Those are after adding 470pf to C402; the OP (Lun Yang BD8BTE) and I had the same issue with the 80m sweep, which was a bit low. In particular, my 60m was also a tad off.
Lun added 330pF, I couldn't find anything except 470pF :-)

Please see below the "before and after" sweeps:

80m BEFORE



80m AFTER



60m BEFORE



60m AFTER




40m BEFORE



40m AFTER



So, by the looks of it, 470pF shifted the center down by some 1.5 - 2 MHz for 80, 60 and 40. Right now, I'm listening to the 80m band and it doesn't seem like any great improvement, but this isn't of course very scientific :-)
One thing that I forgot to mention, after adding the 470pF cap to C402, all sweeps looked totally crazy so my heart sunked into my pants, thinking that I've managed to fry something... turned the thing on and off, but no change. But after a full factory reset, all seem to be ok now.

73,
YO3GFH
op. Adrian
?

-- 
Stefan U. Hegner    <db4st@...>
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