I have just posted a photo of the station accessory I built for my Hallicrafters FPM-300 MK II; dubbed FPM-300SA
The accessory adds:
1. Hi Fi front firing speaker
2. Switchable 14dB gain front end preamp.
3. audio CW filter with an active audio stage to make up for the filter's insertion loss
4. RIT This is really necessary if you don't want to be listening to the other station at a 1400 Hz tone
5. Internal 200W dummy load
6. Custom wattmeter using a meter from a parts FPM-300
Click on the photo of the FPM-300 in the bottom row:
http://www.parelectronics.com/vintage-radio-restoration.phpDale W4OP