The mechanical filter FL101 is 3khz wide and center frequency is 250 khz. So on SSB they will probably set the carrier point for a overall response from 300hz to 3300hz. If it was mine, I would set it from 100 to 3000hz and it will sound very nice on SSB with a decent mic and EQ if it is stable enough frequency wise.
On AM is going to be 3 khz wide and those collins mechanical filter have excellent shape factor, so AM is going to be narrow and restricted. I guess you could bypass the filter on AM with a switching board or get a wider filter and switch that in on AM for bandwidth control. Another idea would be to build a solid state low level modulator and relay switch it in line after the filter and feed the 1st mixer V201. That would be easy to implement and would work well on producing high quality AM, that's what I would do.
You could mount the modulator in a external box, separate power supply. All you would need is a coax from the internal balance modulator after the filter to supply the 250khz carrier to the new solid state modulator and coax right back in to the mixer V201. Tap in the the audio tube too run that in and out. Carrier control & mic gain on the external modulator box too. No hacking of the transmitter and can be easily converted back. I used that same arrangement when I modded my Icom 756pro.
I found a 10kHz wide filter and also found out the filter is 250kHz center frequency. I only want to use the KWS-1 on AM. Although 10kHz is a bit wide on AM my D-104 will only pass 6kHz. Thanks.
