You are right.........Craig is pretty sharp. He was telling me about how he
got started, in a conversation we had a couple of weeks ago. Still, I don't
know what kind of setup you were using with the Mechanical Filters, but when
they are properly terminated, there shouldn't be more than 1dB of passband
ripple. I used several versions of the disc-wire filters for years, before
switching to the Torsional Mode units.
About your filter..........................108dB is a very respectable spec
for that unit! Very good shape factor.
I do like those filters in the 6790..........I have one of them myself.
"Guy Atkins" wrote in message
...
Hi Pete,

Craig Siegenthaler and I have been friends since 1988, so we go back a
ways, and I'm very partial towards his design abilities and products.
Apart from my bias, there's a great value in Kiwa's Premium Filter
Modules-- $75.00 for a filter with typically greater than 100 dB USB
ultimate rejection and shape factor typically 1 to 1.65 is money well
spent. The final, resulting performance depends on the entire receiver
system and PCB layout/shielding, as you mentioned.

The very best filters I've encountered (before I went IF-DSP with the
756Pro) were matched-pair INRAD crystal filters, and the crystal filters
in my RA6790GM.

BTW, before Craig offered filter modules using cascaded ceramics, he tried
the same idea in the Kiwa Multiband AM Pickup (MAP) accessory in the
1989-1991 timeframe. This device provides outboard synchronous detection
plus two IF bandwidths, notch, tone tilt, IF output, low distortion
speaker, and other features. The closest competitor is (was) the Sherwood
SE3.

The filter characteristics in my particular MAP are excellent-- the actual
measurements from the Certificate of Performance show an ultimate
rejection at 3.5 kHz of -108 dB and shape factor of 1 to 1.53 in the
narrow bandwidth (3.0 kHz @ -6db nominal) for my particular serial number.
The passbands are also kept flat within +/- 2.0 dB for both the wide and
narrow IF bandwidths, something you don't always find in discrete crystal
& mechanical filters.

73,

Guy