the rigs that I have to gripe about were (1) National's NCX-3, had a receiver broad as a barndoor both on SSB & CW. I don't think any optional filters could be added without doing your own design changes! On CW you had to be zerobeat with the other station to be on freq, NO OFFSET on receive. You had to keep tuning the dial back to zerobeat when you started to transmit. (2) the Regency hr 2 2M FM rig, the receiver also was bad on this one, picked up lots of out of band signals and had poor audio output. Took the first one back to dealer but #2 had same problems!