> I know the discussion is about Inrad's SSB mod, but wasn't the Inrad
2.8KHz
> filter originally designed to eliminate a CW chirp with some Omni VI's?
Sort of...
Originally, the INRAD 2.8 kHz filter for the 9 MHz I.F. slot was designed to
widen the transmit passband to allow the CW carrier offset to rest sell
within the filter passband and not on the filter skirt as does the stock 2.4
kHz filter. That was only part of the solution. The complete fix involves
using better BFO crystals and a slight re-design of the transmit ALC circuit
to allow slower-ramped leading edge CW waveform while not introducing power
spikes.
As some folks later found, the 2.8 kHz filter made SSB sound a bit more
pleasing in receive when 1) a 2.8 kHz filter was also installed in the 6.3
MHz filter slot and 2) a handful of capacitors were changes to scale-up the
receive audio passband.
-Paul, W9AC
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