Most likely there are not many viewers of Comcast cable that know they are watching all Portland TV stations in delay. All local stations are in a 4 to 5 second delay from over the air broadcasts. This started about a month ago and unless you have TV's using both cable and over the air broadcast, you'd probably never know.

What would be the reason to do this? What does Comcast have to gain?

Are you using some type of cable box or going directly into an analog "cable ready" TV?

The educational access cable channel at my place of employment has experienced a two second delay on older General Instrument boxes that suddenly started a couple of years ago. Some newer DVD and VHS recorders have a 1/2 to 1 second delay as well. Monitoring the same live program material from multiple sources can be nerve wracking if one is delayed. So far there has been no delay on a standard TV.

When I had Dish Network, they openly admitted that they delayed all feeds by 3 seconds... the reason they provided was they were making sure the quality was there. ("tin foil hat" on) Who knows what the real reason was ("tin foil hat" off).

Perhaps they're saving bucks and bouncing the signal off the Moon instead of buying time on a geosync satellite. The moon is a bit more than 1.5 light/sec away so that would account for a little over 3 seconds of the delay.

Randy: I'm using a cable box. I don't know why that would have any effect. As I said this just started about a month ago. I've had the cable box for years and never heard a delay.

This was not 2 or 3 seconds, it was 4 to 5 seconds. I got my stopwatch out and tested channels 2, 6, 8, 10, 12, & 49. Some were in the middle and some were at 4 seconds while others were just a bit shy of 5 seconds. It's a big lag, there is no echo effect.

Craig you might want to post this question over at

http://www.dslreports.com/forum/tvcomcast
http://www.avsforum.com (Comcast Portland Board)

There is a lot of buzz in both these fourms. About what Comcast does from technical stand point.

I live in a triplex and my brother is my next door neighbor I have digital cable converter and his is straight to the tv and when we both have the same channel on I notice a delay.

Here's a though/question.

Is your Comcast box (the one with the delay) a DVR type box?

I know on my Dish Network boxes the ones that are DVR's have a delay while the ones that are not don't.

This is because (from what I understand) they write then read from the hard drive all programming.

Just a thought.

Its not a comcast DVR box but instead the basic digital convertor. Didn't get rid of it when I downgraded to basic in July because I still wanted the option of ordering pay per view if I wanted too.

"Craig you might want to post this question over at"

I just don't have the time to monitor another board. Just thought someone here would know what's going on. My box is a "Regal" CATV converter, Model No. RR-92-3. 92 might be the year it was made.

Dunno about Comcast specifically, but it would be reasonable to expect a certain delay to be introduced by each A/D or D/A conversion. Each device in the Comcast "airchain" probably introduces a noticable delay, much greater than the old analog devices did.

Ther is another reason, the system is "buffered" so that any temperary distortions can be leveled out, before being presented to your screen.

A couple of months ago I upgraded to Comcast Digital which requires a cable box. Before the switch, the sound was in sink with over the air transmission, now there is a delay.

This happens in other places, too: I have heard callers of Dr. Bill Wattenberg's program pose the very same question.

As I understand it (I don't work in the cable industry, so take it with a grain of salt), many cable systems today do not receive over-the-air signals from local stations. Instead, the stations use some type of land-line circuit (I don't know who provides this or what signalling scheme is used) to send a feed to the cable company. Modern systems use digital encoding. It is very likely that buffering would be used if the throughput of this circuit is not constant (like if at some point the data stream passes through a link that is shared with other users). It is also possible that codecs are used that introduce delays.

Comcast has not used over the air signals for years. When TV channels loose power and go to snow. Comcast continues its programming with no drop out.

Craig,
You are perceptive. Unfortunately, you have been so busy working on Portland Radio History that you haven't paid close attention to your Comcast Cable until recently.

Yes, there is a delay. It is all from Comcast. Yes, it is about five seconds. However, it did not start two months ago. It has been that way for several years. We monitor our line out, off air, cable, DirectTV, Dish network signals at the same time and it is confusing. As I say, it has been there for several years.... been so long I can't remember when it started.

Yes, Direct TV also has a delay.

It is in whatever they do at their place. The same signal that goes to our transmitter also goes directly to DirectTV and Comcast via fiber. It isn't the fiber because fiber is how it gets to the transmitter, also. Those are all outputs from the same Distribution Amp. Dishnetwork gets an off air feed so that when the transmitter goes off, the Dish network feed drops, also.

It is as simple as that. The delay on Comcast mentioned above is on the basic analog cable connected directly to a TV. Going through the "analog" converter box, the video is a tad earlier than the straight video. I do not know what it is relative to a digital converter. Don't have one.

In case we missed something on the line out monitor, we just look at the Comcast signal.

Thanks Jimbo.

What it is, is that all the stations feed their signal to Comcast main head end and they take all their signals and multiplex them together and that process is what adds the delay. It just works out to about five seconds. The same should be true with the HD signals, also.