I modded a TS-930S with an Inrad roofing filter which also kills the AM bandwidth. How I ended up fixing that problem was to buy one of their blank roofing filter carrier boards and designed my own 6-pole filter to put on the carrier board. Switching between the two is done by another board and a set of relays; the 6-pole/6KHz B/W filter is inline with the 4-pole OEM in AM and the Inrad 8-pole/2.4KHz B/W unit is the active filter in all other modes. Both really work to tighten up the receiver.
A similar arrangement might be utilized with the '980. My "mule" will probably get the mod and I'll work out the particulars to apply to the others.
73 - Fred, N8YX
