Doppel PS what is it? Panasonic portable

[darklife]

I got a panasonic RF-979(?) radio out of the trash a few years back that looks almost identical to this one here...


Mine was in rough condition as the plastic window for the tuner had a large crack through it and the metal side panel that was glued on was missing. Also my model had black metal panels with silver wording rather than like the one above that has silver panels with black words.

Was a great radio with unbelievably good sound quality. Problem is I gave it to a friend. I only gave it away because my collection started becoming bigger than I wanted at the time.

One thing I could never figure out is what the "Doppel PS" slide controls were for exactly. There was three of them as you can see in the picture above the volume/tone controls and they have part of the FM band labeled beside them and you could set them like presets for stations covering from 88 to around 94MHz and there were push buttons on the top to select between one of these preset sliders or to use the regular tuning dial (which covers the whole FM band from 88-108).

It was a strange setup since buttons (on the very top by antenna) 1 and 2 had to be pressed down at the same time to make the tuning dial work, or else buttons 1 through 3 would make the radio play whatever those sliders 1-3 on the front were tuned to.
What's even more odd is how the sliders are normal linear resistor pots instead of some mechanical setup like most older radios would have for a preset control.

Anyone have information on this radio? I am guessing it was made in the late 60s or early 70s. It has a DIN tape jack on it, and the bands are labeled in what I think is European with UKW (regular FM), KW (shortwave), MW, and LW.

I really regret giving up the radio but we all make mistakes
Wondering just how rare this radio is. I can't find ANY information on it besides one picture on the whole internet and no information on what Doppel PS is.

Thanks.