Analysis of my BPF using Elsie

I havent done anything practical with my BPF since my last Blog, instead I have been scratching my head for reasons why with the exception of 12 and 10 Meters my measurements result in insertion loss values so much higher than I had expected. Either I havent tuned the BPFs correctly or the coils and / or capacitors I have used have a much lower Q than the norm, or the switching diodes have a much higher ohmic on value @ 10 mA than specified. I am not aware of whether there is a "right" way of going about tuning the BPF, the method I used was to use a succession of tweaks on all coils which because of interaction was repeated several times until I achieved a condition that provided a simultaneous minimum insertion loss at both band edges. The Qs of coils and capacitors I have used are quoted as being typically 85 and 2000, and the on resistance of diodes better than 1 ohm. I have not measured any of these independently, but I did try varying the DC bias current through the diodes from 5 to 20 mA and could barely perceive any change on the filter performance, so I doubt if they are responsible.
Although I was previously aware of Jim Tonne's Electrical Filter Software and had downloaded his free version of Elsie http://www.tonnesoftware.com/elsie.html some time ago I had never used it before today, so this morning I decided to explore it further to see if I could analyse my BPF using his software model. I discovered that by using the Manual Parts Entry feature in his program I was able to do this quite easily using the Schematic, Entry, Analysis, Plot and Tune features provided. As an example I have saved a file of a simulation of the 20 Meter Band Pass Filter which I have called 20MeterTuned.LCT at http://groups.yahoo.com/group/BITX20/files/g3oth/ which can be opened and viewed after launching the Elsie program. I am most impressed by this program, and am now going to model the other BPFs using it. The predicted results for the 20 Meter Band are better than I measured, even after substituting Qs as low as 50 and 500 for coils and capacitors respectively, so I suspect there must be something wrong with my previous tuning technique after all.
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