I have finished building an amp using three 811A tubes in GG. For the input tuned circuit, I designed Pi networks to match 50 Ohms to the tube input Z. I used a value of 107 Ohms for the tube input. Plate voltage is 15oo V at full load. The driver transmitter (Kenwood) shows higher than ideal SWR driving the amp. The Kenwood doesn't "fold back", driving the amp, so it will still work. I'm wondering if I have the correct value for input Z to the tubes. The Pi networks are not adjustable, and the inductors are toroids.