There we go. After reviewing pictures of several other amplifiers
using this tube I removed one more turn from the coil on the tube
side of the T match. Input SWR is 1:1 and the amp is making over 600
watts out with 25 watts in. I plan to run it this way for a while
before I go for the real QRO.
Paul
On 05/01/2017 02:40 PM, N1BUG wrote:
I'm seeing more RF output with the new configuration, about 500W for
somewhere around 25W drive. It appears I am going to have some fun
getting the input SWR down but I guess everyone does. That's
probably why there are so many slight variations on coil dimensions
among the various plans.
My first try with both coils having 5 turns 15mm ID, 20mm long
resulted in minimum SWR of 3:1. My second try with 4 turns 15mm ID,
20mm long got it down to about 2.6:1. I am not sure whether to take
another turn off both coils or perhaps just the one on the tube
side. Many pictures of amps I have seen appeared to have less L on
the tube side although I don't see this mentioned in any
accompanying text.
Paul
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