Hi peeps.
Just an interesting bit of info... well to me anyway..
Doing some prep work on a VHF Triband Tranceiver.. I like to make modules I have not made or tested before....
The 6 metre front end filter was first..At 2 Mhz bandwidth, I chose 4 X Ind and 4 X caps... the inductors were suitably tapped to match the analyser.
In lashup mode.. all seemed well.. a reasonable flat ish top ...however looking at other circuits I decided to use a Double gate BF96 fet, to provide a bit of gain and AGC control.. Thus feeding the fet gate directly from the top of L4, I was getting a bit of very peaky responses, thus setting up was... difficult.. I played with various coil spacings and coupling, some were better than others, and I had no room or inclination to put screens between the coils..... so I hit on damping the "Q" of each coil.. I tried 33K at first and it was a much improved situation...finally 22K was chosen. Now I know its not perfect.. see photo..but in the final version, final tweeking should be ok.
There will be outer screening in the finished model