Still got the tapes, still got the Nak in the rack, and still have the Soundstream TC-308 in the work truck. You can use Dolby C with that combo.
I love cassettes for the vehicle because, well ... CDs were never meant for the car environment. Not that they sound bad ... they don't ... but they are an order of magnitude more fragile than cassettes. The iPod mitigates some of that today, but unless you use lossless or AIFFs on your portable media player, the cassette kicks butt.
Plus, there is always the thing about content you can't get anywhere else ... assuming you're in it for the music. There is an interesting thing about analog tape ... whether 2" 24-track or the lowly cassette. It has fairly large amounts of 3rd harmonic distortion (like 3% or more) but not much else. Obviously since pretty much everything from the early 90's and back was recorded in the studio on tape, we don't find it that objectionable.
Musically, it's "a 12th" which is 1 octave + 1 fifth. On pure tones it's easy to hear but on music, not so much; it adds a bit of an edge but it's not harmonically objectionable (within reason). Another interesting thing ... with tape decks and tape formulas, there is always a spec for maximum recording level at 3% 3rd Harmonic Distortion. This was listed as "THD" in the spec sheets, leading people to mistakenly assume it was "Total Harmonic Distortion". With tape, it's not.
'86 you say? A bit too early (by about 2 years) for DAT tape, but Open Reel; VHS tape; Cassette with perhaps DBX encoding are all possible location or radio studio media of the era.
If they used metal tape it was probably just for the headroom, but my experience suggests a TASCAM Portastudio (4-track cassette at double speed) or other mobile cassette unit with/without DBX and TDK-SA 90 **, at the most, was probably more likely ... radio stations are, trust me, stingy to an extreme. There were quite a few good quality 2-channel portable cassette recorders they could have used, from Uher, Nak, and even the Sony Professional Walkman (all 3-head dual capstan units with NR of some kind).
Metal was $15, SA was $3, and a 90 minute tape lasts for 22 1/2 minutes of recording at double speed 4-track in a Portastudio. They could have gone stereo (1+3 then 2+4) and got 45 minutes out of a tape. The other cassette recorders might have got 90 minutes from a tape (some offered double speed, some not).
It gets expensive to record on metal, and NR was cheaper if you actually did any amount of recording ... a DBX unit gets you way past -70 dB S/N on open reel tape, an easy -60 dB on cassette. I've seen radio stations that recorded everything on the cheapest tape you can get, bought by the case (of, like 200), with white no-name labels that came in sheets and you had to stick on yourself. The same stuff the tape duplicators used; the same stuff your pre-recorded tapes from the major Labels are.
Open reel was heavy, needed "real" power, tends to go out of alignment when you move it too much, and not many people used it for live recording in the 80's, even via mobile. Of course, it could have been sent to the station and put to tape there; every station had loggers (by law) so there was a good chance a machine was available. Loggers ran at 15/16 ips (get 24 hours on one reel) but a lot of stations would buy the studio deck at the same time and it would do 3+3/4 and 7+1/2, if not 15.
I'd put my money on VHS HiFi or Beta HiFi tape, but you never know; it was only released in '85. Still, it was very popular with radio and mobile studios for audio. 70 dB S/N, 70dB channel separation, 20~20K, 90 dB S/N in the electronics, battery power was available and the tape was cheap and offered long recording times. Not to be confused with just recording audio on the video track, which was your option on a non-HiFi deck, and was bunk.
** Depends on the deck, but the factory bias was usually set for Maxell on Naks and TDK for most others. Uhers were biased for BASF. Of course, you can adjust the bias for any tape.
Some images:
Sony Professional Walkman http://img.photobucket.com/albums/v729/MokePics2/Audio-Rack/IMG_0406JPG.jpg