Tank coil/cap values

[W7SOE]

The linear amp I am working with (HB) runs out of load capacitance before finding a peak (80m).

I don't know the value of "C1" but it peaks nicely at about half its capacitance.  The inductor is around 20uH which I think is right.

But the load cap (a three section receiver type variable) maxs out with no peak.  There is a .0004uF cap in parallel with the load cap which seems huge.  The load cap is marked 80-1140.  The 80-1140 range seems good but the additional cap has me stumped.

I appreciate any insight.

Rich

[WU2D]

The extra fixed 400 pF is not so strange if you are trying to load into 50 Ohms. I assume that this is a link tuner and you are talking about the input link? Try removing first to make sure that it helps. If it does, add more!

My Gonset GSB-201 Linear which has a conventional Pi network output actually has two of these so you have an 80A 80B and 80C loading cap. B and C have .0005 fixed caps that get put in line so the total can go as high as 1500 pF.

Mike WU2D