C-band history question

[comfortably_numb]

When did the transition from analog to digital C-band happen? Did all services migrate at the same time? Did it require new satellite launches? Since I've only been back in the FTA game for about a year, my last experience was in 1998. At that time, I remember satellites having 24(?) transponders with one video feed each. I also had an SCPC audio receiver that my dad and I built from scratch using a kit.

20 years later, it's all completely different (and better!). Just curious when the changes happened and how.

primestar31 mentioned in another thread the other day that there always used to be 6-degree spacing whereas now it can be as little as 2 degrees. Does that also have to do with the difference between analog and digital RF bleedover?

 

[Titanium]

When did the transition from analog to digital C-band transition happen? Did all services migrate at the same time? Did it require new satellite launches? Since I've only been back in the FTA game for about a year, my last experience was in 1998. At that time, I remember satellites having 24(?) transponders with one video feed each. I also had an SCPC audio receiver that my dad and I built from scratch using a kit.

20 years later, it's all completely different (and better!). Just curious when the changes happened and how.

primestar31 mentioned in another thread the other day that there always used to be 6-degree spacing whereas now it can be as little as 2 degrees. Does that also have to do with the difference between analog and digital RF bleedover?

I am sure many others will chip in, but here are a few of my remembrances...

Satellite transition began in 1997 and continues through today. While most services had migrated by 2005, there were a few hold outs and C-Span and a few feeds are all that remain analog in North America. No new satellites were launched to facilitate digital as the received and transmitted carrier is analog and the data is a digital stream. The analog transponders were simply bandwidth divided into channelized slices. The C-band satellites typically had 24 transponders and the KU would usually max out at 32 transponder assignments.

I recall when the industry went to 4 degree spacing and the problems it caused viewers with older dishes or misaligned feeds. Upgraded many dishes and feeds when they transitioned to narrower orbital spacing and when the technology changed from LNAs to LNBs. It wasn't uncommon to completely upgrade a 3-5 year old system only reusing the pole and charge 2, 3 or more thousand dollars for the upgraded equipment and a day's work. A few years later we would be back installing a LNB with lower noise and a new IRD (Integrated Receiver / Decoder) when encryption hit.

In analog the same 24 or 36 frequency slices had to be reused on each satellite position. One management system to minimize interference from an adjacent satellite was to alternate the polarity assigned to even and odd transponders. For example on one satellite the odd numbered transponders (channels) would be horizontal polarity and the even numbered transponders (channels) would be vertical polarity. On the next satellite Odd would be vertical and the even would be horizontal. On KU some transponder groupings would be vertical and others horizontal. This could be quite confusing when searching for feeds!

 

[comfortably_numb]

The analog transponders were simply bandwidth divided into channelized slices. The C-band satellites typically had 24 transponders and the KU would usually max out at 32 transponder assignments.

So, using a pie as an analogy, each satellite is still the same size pie, it just isn't cut into pieces anymore?

 

[Titanium]

The satellite is the same pie size (the amount of bandwidth is still the same), but the pie is cut up into different size pieces depending on the appetite of the service. Each slice can now either be the size of a single service (SCPC - Single Channel Per Carrier) or the slice can have many services (MCPC - Multiple Channels Per Carrier).

 

[comfortably_numb]

The satellite is the same pie size (the amount of bandwidth is still the same), but the pie is cut up into different size pieces depending on the appetite of the service. Each slice can now either be the size of a single service (SCPC - Single Channel Per Carrier) or the slice can have many services (MCPC - Multiple Channels Per Carrier).

That makes sense. So the old 24 transponder "standard" was a set amount of video bandwidth, whereas now a transponder can be of varying bandwidth?

Is the SCPC of today the same as the SCPC 20 years ago? I remember it only being audio back then.

In fact I may still have that tuner in a closet someplace. If I remember correctly we took an output from the IRD and ran it into the SCPC receiver. I could then tune in many different audio feeds.

 

[Titanium]

That makes sense. So the old 24 transponder "standard" was a set amount of video bandwidth, whereas now a transponder can be of varying bandwidth?

Correct.

Is the SCPC of today the same as the SCPC 20 years ago? I remember it only being audio back then.

SCPC tuners back in the day were tuning the analog audio subcarriers and some hobbyists monitored these audio services using off the shelf scanner radios connected to and tuned to the IF loop out frequency. I used a SDR dongle a few years back and found only a few analog SCPC signals (I think they were on the SatMex satellites). Today SCPC means Single Channel Per Carrier and primarily references that a carrier has a single digital service.

In fact I may still have that tuner in a closet someplace. If I remember correctly we took an output from the IRD and ran it into the SCPC receiver. I could then tune in many different audio feeds.

Not sure if any analog SCPC services are still up there, but if it can still be connected to the IF output an analog receiver and still works, it might be a fun retro test.

 

[clucas]

I hunted down a bill for my first satellite system installed in 1984 when HBO, Playboy and some others were analog and not scrambled. Satellite transmission must have started at least a couple years before that. After I paid $3,300 for the professional install, years later I installed one for my father and I’ve done installs for myself when I relocated.

 

[comfortably_numb]

I paid $3,300 for the professional install, years later I installed one for my father and I’ve done installs for myself when I relocated.

We got lucky: my dad is an EE at Honeywell (formerly Grimes Aerospace of Ohio). He had a friend at work who was a satellite hobbyist.

When we moved to rural London, Ohio in 1993, the only option for TV was C-band. There was a dish on property, and my dad's friend came out and helped us set it up. That is when I learned the "take the receiver and TV outside" method of tuning signals. I was instantly hooked. I spent countless hours moving the dish and looking for wild feeds.

My parents paid for the traditional pay-TV services on C-band through Netlink, but I was far more interested in the occasional feeds and free audio/radio services I could find.

Personally, I think I spent more time using the C-band dish than they ever did, since we also had a very large OTA antenna on a tower pole above the roof.

My parents were some of the first adopters of Dish Network when Echostar began its transition from C-band to DBS, but I continued to use the old BUD until I moved out and went to college.

If they hadn't moved to a rural area when they did, there's a very real possibility I would have never been exposed to this technology. I am truly thankful for those opportunities.

 

[raydio]

Correct.

SCPC tuners back in the day were tuning the analog audio subcarriers and some hobbyists monitored these audio services using off the shelf scanner radios connected to and tuned to the IF loop out frequency. I used a SDR dongle a few years back and found only a few analog SCPC signals (I think they were on the SatMex satellites). Today SCPC means Single Channel Per Carrier and primarily references that a carrier has a single digital service.

Not sure if any analog SCPC services are still up there, but if it can still be connected to the IF output an analog receiver and still works, it might be a fun retro test.

Yes...I remember well hosing the IF loop output from the receiver into a Radio Shack scanner and listening to the many SPSC services that were available back then and there were a bunch -

 

[Titanium]

That is when I learned the "take the receiver and TV outside" method of tuning signals. I was instantly hooked. I spent countless hours moving the dish and looking for wild feeds.

Ever forget and leave your parent's receiver tuned to "that channel" next to TBN? LOL

 

[comfortably_numb]

Ever forget and leave your parent's receiver tuned to "that channel" next to TBN? LOL

Oh yes. And the trouble it caused me

 

[N5XZS]

Ah, those were good old days.... Yes, the 80's and the 90's good time to have with. Don't we want a time machine to go with?