#3 - Zweikanalton / Zweiton / A2 Stereo (and quick comparison to NICAM)

[@gizmothingy25524]

First NICAM broadcast was done in 86 (tests) in the UK. Denmark had a full service starting in 1988. First A2 was in 1981 on ZDF in Germany.

[@mattstvbarn]

I am aware of the UK trials. That was done with experimental hardware very different to the final solution. I specifically referred to public launch. Do you have a source about Denmark? That is interesting. The Philips solution is Danish and was probably completed by 1988 but doesn't appear to have been for sale until 1989.

[@matthewpriem]

I can still remember switching to the Dutch public broadcaster to watch the Eurovision Song Contest because they broadcast in A2 stereo. We had a large Salora TV set from 1985 till well in the 2000’s. When we got our JVC 16/9 TV with NICAM to replace the failing Salora, we finally got to enjoy NICAM stereo on the Flemish channels and the BBC.

[@AttilaSVK]

My parents bought their new 56cm TV in 1990 for about 8-10 months worth of average salary. The Tesla Color 428 had 30 channel presets, stereo sound (only A2 Stereo though), a teletext decoder and was fully remote controllable. Quite something for freshly post-communist Czechoslovakia. Basically, it was a Philips set: everything Tesla couldn't produce (like the teletext decoder chip, the IR receiver chip, etc.), was made by Philips :) I was a baby back then, but this TV lived with us until the mid 2010s. We got cable TV in 1996-7, where the local terrestrial channels were just collected at the head end and frequency shifted, the Slovak TV channels had A2 Stereo, while the Hungarian ones were mono. At least that's what I thought, until my dad bought a brand new Sony TV in the late 90s, which had NICAM Stereo. The other channels coming from (digital) satellite were in regular A2 Stereo, since those modulators were cheaper.

[@Pepek94]

Hungary used NICAM stereo broadcasting.

[@kFY514]

That would confirm that Slovakia used basically the same arrangement on cable as Poland - although here in Poland the "native" standard used by our own broadcasters was NICAM - although that didn't come until 1997; see my recent comment under this video for details. Also, it seems that using Philips components by local brands was common all over Europe. That TV my grandma had that I mentioned in that comment, from the mid-90s, was branded Elemis, which was a name assumed by the Warsaw factory known as Unitra-WZT in the communist era. And indeed, it had Philips internals and basically operated like a Philips set, just with a very funky looking and unergonomic remote 😅 It didn't have stereo or teletext though, as it was the most basic model available, I think. My parents during that time had a Sharp 21N52-E1 set, which was truly multi-system (supporting PAL, SECAM, true NTSC and NTSC4.43, as well as all the audio carrier offsets - systems B/G, D/K, I and M - no SECAM-L or PAL-M/N though), but very basic otherwise - no teletext, and the only form of stereo it supported was through the AV input. However, it lasted us very long - my parents bought it around 1992 I think, and we only replaced it in 2013 in the wake of analog switchoff, and after that it was still handed over to some neighbor who apparently kept using it with a converter box. It was serviced once or twice during that time, but still lasted over 20 years, which is quite remarkable. Those Sharp sets also displayed the color system every time you switched channels, so we could witness the switch from SECAM to PAL in real time (TVP2 switched a year ahead of TVP1, so we were seeing different marks for a while), and I think it was influential in getting me interested in TV tech from my childhood years, as I was intrigued about what that was and how it worked ever since. Also intriguing were the false colors and "Venetian blinds" visible when you switched the TV to NTSC4.43 mode on a PAL signal - of course now I know how did that happen 😀

[@kFY514]

NICAM and A2 actually *can* coexist with system D/K, or more specifically, so-called system D1 which was used in Poland and possibly some other former Eastern Bloc territories. System D1 retains the 6.5 MHz main FM audio carrier as for D/K, but limits the video bandwidth to 5 MHz as in B/G. That additional megahertz of bandwidth can be used for the second FM carrier for the A2 system at 6.258 MHz, and NICAM at 5.85 MHz (as for B/G and L). There are actually a couple of possible frequencies for the second A2 sound carrier for D/K, but that's the Polish frequency at least, and I'm pretty sure it was explicitly chosen so that both can coexist. Or... well, Polish Wikipedia suggests that A2 was apparently colloquially referred to as "Czech stereo", so the choice of subcarrier frequency may have actually come from the south 😅 A2 stereo was never actually broadcast terrestrially in Poland, the standard of choice for that was NICAM. But reportedly A2 soundtracks were passed through without re-encoding for some foreign channels in cable networks, much like SECAM color was not re-encoded for channels coming from e.g. Russia, even after all domestic TV switched over to PAL (and I vividly remember seeing Russian channels in black&white with SECAM subcarrier artifacts on my grandma's cable on her then-brand-new PAL-only set back in the day). So you needed a pretty multi-system TV to receive everything that there was on cable in both color and stereo. I don't think there was any channel that actually used A2 and NICAM concurrently, but it was technically possible and is documented as such in Polish sources. So you could in theory have 4 discrete audio channels (2 analog and 2 digital) on a single TV channel on Polish analog cable.

[@kFY514]

Just to update on my previous comment from 9 days ago: in Poland there was a similar situation, where the market was full of A2-capable sets, but the standard of choice for stereo on our TV was NICAM. Some people could make use of the A2 sets though, watching foreign channels on cable (or terrestrial near the borders). BTW, I'm pretty sure that Czechia and Slovakia used a variant of A2 as well. Also, given that in our D/K regions the A2 and NICAM carriers got placed _below_ the standard mono sound carrier, there actually was crosstalk with vision signal - but in reverse. One some sets, particularly older, single-standard ones, you could see the NICAM sound get interpreted as high frequency vision content. Anyway, to reiterate - you can get both NICAM and A2 concurrently on system D/K and I'd love to see how a modern set like this Samsung deals with that, whether all 4 available channels would show up. Maybe if I finally get myself a HackTV setup I could check it myself ;)

[@mattstvbarn]

@@kFY514 interestingly Philips only made one version of the PM5588 - the B/G version. If A2 on D/K was commonplace I'm fairly sure they would be flogging equipment for it. You sure it was done? Or was it the NICAM carrier which was moved? What were the actual frequencies?

[@kFY514]

@@mattstvbarn I posted everything in the previous comment that you seem to have missed. But just to reiterate, here in Poland, NICAM was on 5.85 MHz, just like for systems B/G and L. There were a couple of different A2 secondary subcarrier arrangements for D/K, but what was used here (on cable only) was 6.258 MHz. And Polish sources explicitly say that this system allows for both NICAM and A2 to coexist. There's also another comment under this video posted about a year ago by a viewer who goes by @AttilaSVK who recalls receiving A2 stereo in Slovakia and comparing those to broadcasts from neighboring Hungary, who went with NICAM. No comprehensive list of countries who used A2 seems to exist, but A2 on D/K was commonplace enough that Wikipedia lists three possible frequencies for the secondary audio carrier 😅 And I am fairly sure that it was indeed used in Czechia and Slovakia at the very least.

[@mattstvbarn]

@@kFY514 apologies. The channel does get quite a few comments. I don't always get to reading them all!

[@kFY514]

@@mattstvbarn No worries! But as you can see, you might be missing some interesting information ;)

[@mtc2300]

The days when you would look through the TV guide for the oo sign on German channels. Though they didn't use Zweikanalton over satellite (Originalkanalton nicht über Satellit).

[@der.Schtefan]

Well, the R+S device is a "Messdemodulator", so it is a measuring (Mess-) demodulator for the lab or trouble shooting. That's PROBABLY the reason why it does not need to be able to demodulate both channels at the same time.

[@altebander2767]

Actually we had a poor reception of Austrian A2 or ORF1, and I distinctly remember watching Golden Girls on it which had the original audio on the second channel, and it sounded way better. I'm not sure why this was. Austrian was a late adopter of A2, so they might have played around with the power levels of the carriers, or maybe it was caused by the interference of the Czechoslowakian TV station which was 500 kHz above ORF1.

[@kabalu]

sehr gut

[@namesurname4666]

i think this was also used in italy by rai and some other channels, the rest were mono

[@mel816]

South Korea was also the only non-PAL country to implement Zweikanalton/A2 stereo.

[@ksrele]

What system was used in Serbia? We had a analog channels with stereo sound but I don't recall that they ware digital. I someone had mono TV he could build external stereo demodulator that was very similar to radio FM stereo demodulator.

[@mattstvbarn]

I'm not sure. Serbia has not ever been listed as an A2 stereo or NICAM country on Wikipedia if you find out and can have a reference perhaps worth updating one of those pages.

[@ksrele]

@@mattstvbarn Just realise now that Serbia was part of country Yugoslavia (there is no more Yugoslavia, only Serbia and rest Ex-Yu countries) so maybe that country was listed somewhere?

[@granttaylor3697]

Hi Matt, Good video, I have send you some information on what I am currently doing with AM Stereo / FM stereo that maybe of interest?

[@mattstvbarn]

I'll check it out. And cheers for helping with the info for the video!

[@j7ndominica051]

Stereo reception on radio is often noisy, while TV always blasted loud and clear. I used to think they could use two parallel stations to send stereo more clearly and simply. Mono radios were much cheaper and a home usually had at least two of them that could have provided an easy compatibility. NICAM seemed to be quite robust (on a late integrated Philips receiver that I unfortunately threw out). The TV could lock onto the signal with a short cable as an antenna. We had cable television where they briefly translated the dual audio on separate channels, and I checked NICAM over the air as a curiosity.

[@kerbalwww2]

Can you scan and upload the manual for the Zweiton demodulator? edit: Same for the philips pm5588.

[@mattstvbarn]

I don't have any documentation for it. Would like to find it however!

[@mattstvbarn]

I've scanned what I have for the PM5588. Link is in the description. Not a full manual unfortunately but it gives a good overview.

[@kerbalwww2]

@@mattstvbarn Thanks I wand to lean more about Zweikanalton but i can find not so much info in the internet.

[@Pepek94]

Zweikanalton possibly used in Bulgaria and in some Arab states since Israel adopted NICAM standard.