[HomeBrew] JW Miller 15-H IFs in series

[Sandy and Kees Talen]

Is there something I'm missing on using IF's in series ?

I connect 2 of the subject, retuned to 100Khz, JW Miller, 
15-H, IFs directly together and because of overcoupling see 
a "double hump". This is not necessarily bad because it 
"flat tops" the passband like a crystal filter. The BW goes 
up a little from 3.8Khz to 4.2Khz but the -20dB BW drops 
from 15Khz to 10Khz which is really good.  Using capacitive 
coupling between the IFs of 5-10pf the waveform is a little 
distorted and peaked ....and the -20dB BW goes to 8.5Khz. 
The -6dB BW actually goes up to 4.8Khz.

These are a little more difficult to tune up because it's not
just peaking (on the capacitively coupled ones) it's also
passband shaping. The direct (overcoupled) set is easier 
to tune up because just peaking will get you there.

73s  Kees K5BCQ