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DTV Subchannels: What does it take?

sdwulfdawg

sdwulfdawg

I'm curious: what does it take for a station technically to transmit a DTV subchannel? Extra transmitting equipment? Is the programming subject to E/I requirements?

I would think that stations and/or FCC would want to encourage local programming developed by other program outlets (of course, non-competing) to be carried on their extra channels...

Bueller?
 
It is subject to E/I programming requirements. You can transmit a radar 24/7.. but you still have to break format to run some E/I programs once a week. (I usually see them on Sunday mornings)

Stations that have subchannels have to have equipment to input the programming onto that subchannel. In the master control you'll have to have somewhere set aside for just that subchannel so you can run commercials, satellite or taped programming, etc. I can be done with computers fairly easily. There's a TV equipment company that actually created a product for stations called "channel in a box" that has everything a station needs to create a subchannel. (aside from whatever they have to do with their transmitter)
 
I was looking at your post from a different angle.

What does it take for a station to decided to add sub channels?

It takes a strong and visionary station to add sub channels in these economic
times. While the competition across town is eating doughnuts and reading the
Enquirer, they see the growth and potential which lies ahead. As with anything
else, the sooner you get on board, the better!!!

Many of the "heritage" stations have lost the spirit upon which they were founded.
They can't see the smoke signals from beyond which their founding fathers are
sending. They've simply lost the UMPH and GUMPTION they were created with.
Bigger is always better in broadcasting. Now, that one channel can be split into several,
why have one olive tree when you can have an olive grove?
 
tested said:
It is subject to E/I programming requirements. You can transmit a radar 24/7.. but you still have to break format to run some E/I programs once a week. (I usually see them on Sunday mornings)
Click to expand...

It's usually Saturday mornings around here.

Back when WKYC/3.2 was NBC Weather Plus, that network used to run "weather educational" segments from the network weekdays at 1 PM, with segments teaching weather information.

For whatever reason, the network programming didn't work with the local L-bar...so there were no local temps/forecasts/etc. in that hour (since there were also no local video inserts that hour).

The network had its own L-bar in that hour, with national conditions and big city forecasts (much like the Weather Channel on satellite).

Now, I believe WKYC's local radar channel just throws in standard E/I programming on Saturday mornings.
 
Does running subchannels require extra transmission/electric cost? Beyond any extra equipment the station might have to buy (if they don't have some laying around or to cannibalize)? It's (at least close to) the same power and electric cost and reach involved, it's just split up into more signals, right?
Or am I way off?

If they had the equipment, and didn't have to take out mortgages for it, wouldn't it cost very little to just throw up RTV or Antenna TV or some other programming until they could figure out what they wanted to do? Seems like that was one of the things the FCC promoted back in 09.
 
tested said:
(aside from whatever they have to do with their transmitter)
Click to expand...

Nothing needs to be done with the transmitter itself. A digital TV station broadcasts a 19.2MBPS datastream -- the data rate is fixed, the station *must* transmit that much data for receivers to be able to decode any of it.

If a station doesn't *need* the full 19.2MBPS, it can transmit "null packets" (I suppose you could call them "digital dead air") to fill.

To add a subchannel...

- As you say, you need the equipment to provide the programming. Satellite dish and/or video server; switching arrangement; source of E/I programming; (and EAS which is also required for subchannels) monitoring gear.
- You need an MPEG encoder. The programming is switched uncompressed, probably SDI. Digital TV broadcasts are MPEG-2 compressed.
- You *may* need to replace your stream multiplexer. A multiplexer is used to at least combine your audio/video stream with metadata. (PSI and PSIP) If your multiplexer doesn't have any available ports for the MPEG from the new subchannel, you'll need to replace it with one with more ports. Many stations already have spare ports & won't have to do this.

From a hardware standpoint, it's not very expensive. I'm seeing suitable standard-definition MPEG encoders for as little as $1,500 on eBay. There's an 8-input multiplexer on eBay for $1,250.

_________________________________________________

gregg75 said:
why have one olive tree when you can have an olive grove?
Click to expand...

Because the water, fertilizer, and the labor to harvest the olives are all proportional to the number of trees - if the market for olives in your town is small enough to be supported by one tree, you probably don't want a grove ;)

The cost isn't in the hardware. It's in the rights costs for the programming; in the cost of suitable E/I material; in the EAS gear. (which I suppose *is* hardware!)

It's by no means a given that you'll be able to sell enough advertising in the subchannels to pay for the programming.

_________________________________________________

Also, while you can't transmit less than 19.2MBPS - and have to fill with nulls if you don't have that much data - you also can't transmit more than 19.2MBPS. Adding subchannels requires more aggressive MPEG compression of the channels you already have. At some point visible artifacts appear. Most viewers feel one HD program and one SD can be broadcast in reasonable quality. Some feel *any* splitting is a problem.

_________________________________________________

Oh, I don't like olives...
 
quadraphonic said:
Does running subchannels require extra transmission/electric cost? Beyond any extra equipment the station might have to buy (if they don't have some laying around or to cannibalize)? It's (at least close to) the same power and electric cost and reach involved, it's just split up into more signals, right?
Or am I way off?
Click to expand...

No, you're absolutely right.

When we added a subchannel 18 months ago, we didn't even have to go to the transmitter. All the changes were made at the studio.

_________________________________________________

Oh, with regard to E/I and EAS.. I've heard of stations (not ours!) using Conditional Access ("scrambling") on weather subchannels.

The idea is to use the subchannel to feed the weather channel to cable operators. (who are given the "descrambling key") Apparently if the subchannel is not accessible to the general public, E/I programming and EAS are not required.
 
w9wi said:
Oh, with regard to E/I and EAS.. I've heard of stations (not ours!) using Conditional Access ("scrambling") on weather subchannels.

The idea is to use the subchannel to feed the weather channel to cable operators. (who are given the "descrambling key") Apparently if the subchannel is not accessible to the general public, E/I programming and EAS are not required.
Click to expand...

The only two I can think of off-hand are WAVY in Hampton Roads and WTNH in New Haven.

- Trip
 
In response to the olive grove and small town comment.

Sure there will be costs up front and it may take awhile to turn a true profit, but you plant
the seeds today and reap the profits later on. The sooner those seeds get in the ground, the
sooner they will grow and earn some profits.

Stations do have a choice, aim for the moon today and accept the costs or save your money
and hope the competition hasn't gotten there first when you decide it's the "right" time. Most
seem to be taking the later choice........and it just might come back to bite them.
 
tripinva said:
The only two I can think of off-hand are WAVY in Hampton Roads and WTNH in New Haven.

- Trip
Click to expand...

They are sister stations.

WFSB Channel 3.3 Eyewitness News Now shows a really bad kids show call Gina D's Playhouse. Saturday Mornings. They take off the scrolling news headlines and weather information during this.

WVIT Channel 30.2 NBC Weather Plus show various kids programming and they leave the weather information on the screen.

WCTX Channel 59.2 The Cool TV shows E/I that I think originates with The Cool TV as I have seen their logo in the corner of the screen during E/I programming.

WCCT Channel 20.2 THIS TV uses programming provided by THIS TV for E/I.

WTIC Channel 61.2 Antenna TV will be using programming provided by Antenna TV for E/I.
 
I think you also get E/I programming with Qubo. That, of course, would be with WHPX-DT 26-2 from New London, CT (to complete your Hartford/New Haven list).
 
Our station carries Telemundo on our .2 subchannel; E/I material (from qubo, IIRC) is part of the Telemundo programming.
 
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