Will ghosting end with analog?

[scandia101]

A couple of the local channels I receive with cable that are on the same channel number as the analog OTA signal regularly have ghost images just to the side of the real image. It's been going on for as long as I can remember and I rarely give it a thought. I assume it's caused by both the analog OTA and the cable signal being received. Will this end with analog, or could it be caused by something else?

[stevel]

Well, if it is indeed the OTA analog signal causing the ghosting, and that's very possible, then yes, the ghost should go away when the analog OTA signal is turned off.

[scandia101]

Thanks, but DUH.
I guess I should have worded it more carefully.
Is this ghosting caused by the analog OTA signal interfering with the cable signal, in which case the ghosting will end with analog OTA? or is ghosting possibly caused by something else?

[RoyK]

Ghosting is caused by receiving the same signal (channel) twice (or more) slightly out of time phase . It could indeed be caused by pickup of both the OTA and cable signals. It can also result from reflections of the signal - say from a mountain or building.

Most likely your guess that it's OTA interfering is correct. I had a bit of that too here until I replaced all my cables with RG-6 properly terminated with crimp connectors and installed with a good crimp tool. And I mean replacing ALL cables - especially the cheap ones that come with TVs, DVD Players, and - yes - TiVos.

Oh - and pick up some 72 ohm terminators to plug any unused inputs on splitters.

[scandia101]

Most likely your guess that it's OTA interfering is correct.
most likely is good enough for me.
Thanks.


Oh - and pick up some 72 ohm terminators to plug any unused inputs on splitters.

If I'm splittin' it, I'm using it.
New question, would capping unused rf outputs on a Tivo be at all benneficial?

[David_NC]

Thanks, but DUH.
I guess I should have worded it more carefully.
Is this ghosting caused by the analog OTA signal interfering with the cable signal, in which case the ghosting will end with analog OTA? or is ghosting possibly caused by something else?

The OTA pickup of the signal does cause the ghosting - thats the reason most cable systems remap the local stations to a different channel.

After the digital transition, you will not see any ghosting on the picture. If the signal were strong enough, it might cause reception problems, but it would cause loss of digital data, not a ghostlike image.

[JimSpence]

However, what causes ghosting in the analog world causes what is called "multipath" in the digital world. Multipath prevents the ATSV tuner from locking onto the signal altogether. Thus, it is more important to get the right OTA antenna and have it aligned as correctly as possible.

[RoyK]

most likely is good enough for me.
Thanks.


If I'm splittin' it, I'm using it.
New question, would capping unused rf outputs on a Tivo be at all benneficial?

Couldn't hurt. And its cheap. (I don't do that however - mainly because I didn't think of it.)

[RoyK]

One other troubleshooting thing. If you have a TV you can easily move take it to where the cable enters the house, disconnect everything else and connect the incoming cable directly to the tv. If you still see ghosts call the cable company - they have a problem and they will fix it.

Did that here a few years ago and they did have a bad connector in their line.

[mattack]

A couple of the local channels I receive with cable that are on the same channel number as the analog OTA signal

(Isn't it only channels below 12 or so that are the same frequencies on cable as on OTA? I'm too lazy to look it up.)

But anyway, yeah... and that's the reason most cable companies DON'T have the channels on the same channel number.

Ghosting will go away, but you may very well get macroblocking instead. I love DVDs, and have 2 HD-ready Tivos (still currently only getting analog over cable)... but really prefer analog degradation to digital degradation.. since there essentially isn't any (dropouts are worse than snow)... For things like DVDs which comparatively rarely have problems, it's great.

BTW, I'm _not_ intending to sound like some Luddite. The "forced" transition to OTA broadcasting is one of the times that I think "obsoleting" people's equipment was a reasonable thing to do, since the spectrum is a shared resource.

[Martyp]

It also could be tht your cable company has bad lines and its letting the ota signal in

[David_NC]

We used to have the ghosting problem here years ago, before the cable company remapped the local channels. A couple of stations are only about 20 miles away, so the TV is watchable with no antenna connected at all.

[scandia101]

We used to have the ghosting problem here years ago, before the cable company remapped the local channels. A couple of stations are only about 20 miles away, so the TV is watchable with no antenna connected at all.

Most of the local TV towers are 20-30 miles from where I'm at, so there's a good strong signal to be picked up.

[hefe]

Ghosting is caused by receiving the same signal (channel) twice (or more) slightly out of time phase . It could indeed be caused by pickup of both the OTA and cable signals. It can also result from reflections of the signal - say from a mountain or building.

However, what causes ghosting in the analog world causes what is called "multipath" in the digital world. Multipath prevents the ATSV tuner from locking onto the signal altogether.

Multipath is the cause of problems in many RF situations, be they analog, digital, television, radio...anywhere there is RF, multipath can occur. It simply means that you are receiving copies of the same signal at different times. Usually, that is due to a reflection somewhere, and you have a direct, and an indirect signal that are out of phase with each other. Sometimes you don't even have a good direct signal and have multiple indirects of similar strength.

In the analog world, the result is usually ghosting. In the digital world the receiver starts losing bits, and the whole stream breaks down. Different frequencies reflect and carry differently, and sometimes you can experience multipath problems with one channel and not another even if they originate from the same location.