70cm / 23cm Diplexer design

[VK2GOM]

I am looking to design a diplexer for 432MHz and below (ie. including 2m) on one port and 23cm on the other, that is, to feed two antennas (a 2m/70cm dual band vertical and a 23cm Yagi) with one run of coax. The diplexer will obviously be mounted at the antennas.

I downloaded the Elsie filter design software and had a play. For a capacitor input highpass filter, Chebyshev 5th order and an Fc of 747MHz (geometric centre of 70cm band top edge and 23cm lower edge) it is giving me some component values and the frequency plots look good.

Next question, has anyone built their own diplexer using this software? How accurately in use did it reflect the computed design?

Any other pointers I should be looking at, or other design software out there?

73 - Rob VK2GOM / GW0MOH

[VK5RC]

I used Elsie to design a sharp edged low pass 20m filter for the HPSDR power amplifier (?Penny Whistle) which has quite a high level 2nd harmonic, the resultant filter worked well and was within the tolerances of the components (esp my hand made coils).
If I recall it has a feature to 'redesign' using standard values esp for C and was quite nice to use.
I have not used Elsie for a duplexer design.
regards Rob VK5RC