Want to resurrect your D/D2 MAC kit?

[Captain Jack]

What did it look like? Videocipher II messed with sync pulses, which MAC system does not have. I believe the only similarity is the addressing/access control system that is similar vs actual scrambling (which must have been cut and rotate).

 

[BSBSquarial]

The only image I can find of a scrambled BSB image from The Movie Channel.
Looks like cut and rotate.

 

[BSBSquarial]

FSPhil.
Have you managed to get any further with the BSB receivers and HackRF?

 

[Captain Jack]

He's still working on it (but I keep bugging him often ). I tried it on my BSB receiver that @s-band sent me and it works but loses lock and has no sound. It does, however, decrypt soft scrambled Eurocrypt, which suggests that it's almost the same system with only a different authorisation system.

One way to get it working properly is to use fl2k device (£10 on Amazon) and bypass the tuner - so you'd be piping pure MAC signal directly into the receiver. I have diagrams for Philips and Fergus on receivers to do this and they are very simple mods. However, I'd wait for Phil to see if he succeeds doing it the original route via tuner.

 

[fsphil]

Still no luck with audio on BSB boxes, but the picture quality is quite good now. The non-BSB decoders are playing the sound just fine.
I don't suppose we have any ex-BSB engineers here?

 

[DMAC 405]

Hello all,

I'm new to this site. Found when searching for DMAC encoders for any possibility of resurrecting my BSB receivers. This is great stuff!! I would really like to send RF DMAC from my house to my workshop at the bottom of the garden to be received on a Squarial feeding my old Fergy and Philips boxes! I don't know anything about HackRF but looks exciting. I want to learn more. How do I encode baseband MAC from SD component signals?

I'm looking forward to the possibilities, keep up the good work!!

 

[Channel Hopper]

Your profile mentions SIS equipment and vans, what exactly do you have in your toolbox for uplinking (horizontally) ?

 

[DMAC 405]

Your profile mentions SIS equipment and vans, what exactly do you have in your toolbox for uplinking (horizontally) ?

I work mainly in broadcast TV (camera) as a freelancer. The toolbox sometimes includes a satellite truck- Merc Vito with Ka Band dish for Astra 1L for the UK's main commercial broadcaster.

 

[DMAC 405]

Still no luck with audio on BSB boxes, but the picture quality is quite good now. The non-BSB decoders are playing the sound just fine.
I don't suppose we have any ex-BSB engineers here?

Hello, I'm new here, hope you don't mid me chipping in- fascinating topic!

This rings a bell, I remember when playing around with D2MAC converted BSB boxes in the 90's I could get sound on NRK which was DMAC on Thor (or was it Sirius?) the former BSB Marcopolo sat. No sound though on an unconverted BSB box despite good locked picture with strong signal level. I recall NRK DMAC had about 4 radio channels as well as teletext, none accessible on the unconverted BSB box.

If I remember all BSB uplinking was done by the IBA, it was their specs and infrastructure, BSB just supplied the programming. There's some good youtube videos that show the uplink station and interviews with IBA engineers. Be good to think some may be on this forum?

 

[fsphil]

This rings a bell, I remember when playing around with D2MAC converted BSB boxes in the 90's I could get sound on NRK which was DMAC on Thor (or was it Sirius?) the former BSB Marcopolo sat. No sound though on an unconverted BSB box despite good locked picture with strong signal level. I recall NRK DMAC had about 4 radio channels as well as teletext, none accessible on the unconverted BSB box.

Ah, interesting. There's two types of Service Information (SI) packets in D/D2-MAC and my current theory is that the BSB boxes only understand the more complex type. My code sends just the simple type, and I wonder if NRK did the same. I've evidence that BSB (or the IBA) sent both types, at least at the time of the satellite's shutdown.

 

[Channel Hopper]

https://www.etsi.org/deliver/etsi_i_ets/300200_300299/300250/01_60/ets_300250e01p.pdf

Page 68 onwards deals with the audio part, though from memory D2MAC design halved the total audio section of the DMAC specification, meaning NRKs radio options were ignored by the dedicated boxes.

 

[fsphil]

I think the audio itself is fine, the missing link seems to be the service information. The BSB boxes are showing "NO SI" or "SI GC" on the diagnostics screen, and I'm assuming GC stands for Golay Coding. Unfortunatly the part of the spec that deals with this (page 173+) is extremely vague on how the codes are actually applied.

 

[fsphil]

And here's a Philips BSB receiver finally decoding some audio! The SI packets are still not being decoded, but I realised the decoder probably had a default state including an audio channel address. So a bit of brute forcing later I found it.

Sorry for the poor video quality, I can't do a direct capture at the moment.

 

[DMAC 405]

And here's a Philips BSB receiver finally decoding some audio! The SI packets are still not being decoded, but I realised the decoder probably had a default state including an audio channel address. So a bit of brute forcing later I found it.

Sorry for the poor video quality, I can't do a direct capture at the moment.

This is brilliant, well done!! I found my two lonely BSB boxes, patiently waiting since 1992 to come back to life

 

[fsphil]

This is brilliant, well done!! I found my two lonely BSB boxes, patiently waiting since 1992 to come back to life

Out of curiosity, do you remember if Sky where able to change the channel names on the on-screen display for the few years they ran the MAC service? I can only get the Philips to display the BSB names. (Now, Galaxy, etc.).

 

[Channel Hopper]

Out of curiosity, do you remember if Sky where able to change the channel names on the on-screen display for the few years they ran the MAC service? I can only get the Philips to display the BSB names. (Now, Galaxy, etc.).

Hardly a 'few years'. I think there was around six months at the most for the five/six stations, all shutting services down around mid 1991 at the latest.

 

[fsphil]

Ah my timeline might not be too accurate. I've read that Sky continued to broadcast their own channels on Marcopolo 1 until the end of 1992.

 

[Captain Jack]

Another demo...

 

[Channel Hopper]

Ah my timeline might not be too accurate. I've read that Sky continued to broadcast their own channels on Marcopolo 1 until the end of 1992.

You are correct, the last transmission was December 31, but the channels were already marked as BSkyB names, and from memory I don't think the channel names were on the screen, but were captured by the receiver during tuning and then displayed during a channel change (or when the info button was pressed. You might have to find a post merger receiver (Amstrad 600 / 650 ?) to find out if this was the case.

The link shows the encoding changes during the changeover, might be of use.

 

[DMAC 405]

Sorry my pic didn't work? Tried again. I thought channel names were programmed into the eprom for each channel/frequency allocation.

From memory Power Station was the first to close quickly followed by Galaxy very soon after the "merger" was announced. The final close down is on YouToob. I think they were replaced by Sky News and Sky One. By the end only The Movie Channel survived from the original BSB services, not sure what else was was on from the Sky line up.