I have lost some channels on my TV.
I re-scanned with no change.
What's strange is I get channel 11-11 but none of the other 10 channels of 11?
I have a compass glued on my outdoor antenna, so I now it is pointed in a repeatable direction.
Any ideas what is going on?
Thanks. Andy
Yes. John T.
Look on the TV station web site. It might just be them.
A subchannel can have any number from 1 to 99. They don't have to be consecutive. Since the subchannels are all coming from the same location, and at the same frequency it would be strange to get one but not the others.
The TV station is allocated a certain bandwidth. They can send one or two programs (subchanels) at a high definition or several at a lower definition.
Normally the case, but in the case of channel 66, I think it is, f rom DC, it has 10 or 12 subchannels, and the first 5 or 6 transmit from one location and I can get them, but according to some webpage the others are from a location farther away. Only example I know of.
Also, I hesitate to mention this since I haven't tested, but channel 2 is a major channel for me and it's right here in Baltimore on "Television Hill", and afaicr it works just fine, but 2.3 has outages for 2 or 3 seconds. Starting a week ago, I record Law & Order from 2.3 and I'm not there at the time so I haven't checked if 2.1 is working right when 2.3 is having these outages. I'll try to check in the next couple days.
WMAR broadcasts on 4 multiplexed subchannels, 2.1, 2.2., 2.3, and 2.4. FCC bandwidth limitations allow a digital TV station with one HD signal to multiplex 3 SD subchannels. If a station wants to transmit 2 HD subchannels, it can only accommodate and additional 1 SD subchannel. Since WMAR operates 2.1 as a HD signal, we can assume that 2.2, 2.3, and
2.4 are all SD transmissions. To enable the multiplexing, the magnitude of signal compression for the 3 SD signals must be greater than the magnitude of compression used on the HD signal in order to provide sufficient bandwidth for all the information required by the HD signal (channel 2.1). So, we know that channels 2.2 - 2.4 are relatively highly compressed.Why is that relevant to your problem? Any interference, such as aircraft interposition between your antenna and the transmitter's antenna, or producing multi-path signals, extraneous pulse noise, etc. that is likely to adversely affect HD TV reception will have a greater effect on a highly compressed signal than on a less compressed signal. Therefore, you might find that you're getting more drop outs or other reception problems on 2.2 -2.4 than on 2.1 even though the transmitter's effective radiated power will be the same for all 4 subchannels. If you are anywhere near the flight patterns used by BWI aircraft or by Baltimore traffic helicopters, you're probably having multi-path reception problems. Short of using a very highly directional hi-gain antenna with a rotor on the mast, it's a difficult problem to resolve. Or, a local amateur radio operator's 2 meter transmitter could be improperly creating a 4th harmonic signal that would be quite close to the 0.55 meter wavelength of WMAR's signal. Good luck.
Does that one channel come in solid? In my experience, I've never seen one channel come in fine, the other sub channels not come in at all. When they are flakey though, not unusual to see one come in somewhat OK, but others worse. HDTV is highly unpredictable, unless you're in good, clear range and have the right antenna. I've seen stations that come in fine many days, but breaking up badly or go on other days. It can change within a couple of minutes from fine to unwatchable. And it's not like it's predictable, that it's only during bad weather. Wind seems to be one factor, but there are times when there is no wind, weather seems OK and it can crap out. I guess that's one reason why so many are still cable customers.
My reception got better on the bad channels.
I think it might have been due to atmospheric conditions.
Andy
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