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OTA connection with TV set to "Cable" mode

J

justthenumbers

The thread below about Charter Channel 116 reminded me of something I've been meaning to ask for a while...

I have rabbit ears hooked up to my TV, but I have the "Cable" mode turned ON. (This isn't my normal setup...I'm just doing this so I can properly explain this phenomenon).

With this setup, I am able to get the OTA signal for UHF stations on other dial positions. Through OTA Channel 44, the "other" channel is located 51 spots higher on the dial:

KNXV-15 is on Channel 66
KPAZ-21 is on Channel 72
KAZT-27 is on Channel 78
KTVW-33 is on Channel 84
KTAZ-39 is on Channel 90
KPDFCA-41 is on Channel 92
Channel 42 (don't know calls) is on Channel 93
Channel 43 (don't know calls) is on Channel 94
KPHECA-44 MIGHT be on Channel 95 (can't tell - signal is too weak)

Starting with Channel 45, however, the "other" channel is 56 spots higher on the dial...

KUTP-45 is on Channel 101
KDTP-48 is on Channel 104
KPPX-51 is on Channel 107
K53GF is on Channel 109
KASW-61 is on Channel 117

An even more bizarre occurrence is that, for many channels that are not occupied by an OTA broadcaster, I am faintly receiving the CABLE network that's carried on that dial position. For example, MTV is cable channel 29, and with this setup, I am seeing a very fuzzy MTV on Channel 29. And oddly enough, even though KUTP is OTA Channel 45, with this setup, I am faintly receiving the cable channel that holds that dial position: Court TV.

So why do either of these happen???
 
I should point out that, for three channels, the reverse of the first phenomenon occurs if I have the reverse setup -- cable connected directly to the TV, but the TV set to broadcast-only mode...

Cable Channel 65 (MSNBC) appears on Channel 14
Cable Channel 66 (Speed) appears on Channel 15
Cable Channel 70 (Weather Channel) on Channel 19

There is nothing carried on Cable Channels 67, 68, 69, 71, 72, or 73...if there was, I have a feeling they would be viewable with this setup on Channels 16, 17, 18, 20, 21, and 22, respectively.
 
That thread goes into some detail about why the off-air channels appear on different channel numbers when your TV is set to the "cable" mode.

The other side of your question was about why you were receiving faint images from cable channels on the other channels when you presumably were not connected to cable. The reason that this can occur is because the cable company's equipment is radiating a very faint signal, and that signal is being picked up by your antenna. The FCC has regulations about this, since these radiated signals can potentially interfere with both broadcast television service and also with many non-broadcast applications (such as the aeronautics band that is between the FM broadcast band and TV channel 7). If the radiated signal from your cable company is strong enough for you to see a picture on these channels, that probably means that they're violating the FCC rules...
 
back in the early 90's I did not have cable but had a large home mede uhf yagi (for amateur tv) and figured out that I could get several cable chanels very clear including showtime, now in digital times I doubt that you could still get the pay channels. I had been meaning to try it again becouse when I had cable the pic was lousy (looked lossy) I'm sure the tap is bleading RF (probably pretty good).
 
On the cable system in the town where I live (Comcast), the major VHF channels in the area (2, 4, 5, and 7) are on channels 22-25 on the cable-ready channel lineup. 7 used to be all alone, up on 58, but eventually changed to 25, probably because nobody could find it. Channels 2 and 4 on the cable-ready lineup are not used at all. However, channels 5 and 7 are. And for years and years (I think it still happens occasionally, but I receive all my channels in digital now, so it doesn't really matter anymore:)), I used to get interference lines on channel 3 (used to be QVC on the cable-ready lineup, and now it's CN8). And on channel 7, which is, interestingly enough, WSBE Channel 36, the PBS station from Rhode Island, I would sometimes get interference from WHDH. This always happened at the same time. And I remember one day, I discovered that the noise lines that were seen on channel 3 were actually synchronized with the audio on WGBH, which was on cable-ready channel 22. It used to drive me crazy. And I even remember one time when the interference was REALLY bad, Channel 95 (then C-Span 2) had a very snowy picture, and the audio from WJMN on it, just as if you were trying to listen to the station! I think 96 (ESPN Classic) had WZLX, and 97 had either WODS or WMJX. Channels 98 and 99 were not used. I always wondered what exactly caused this interference. Sometimes it was really bad, and the channels affected by it were unwatchable, and sometimes there was no problem at all. The cable technicians could never figure this out, and apparently, they got very frustrated with it. Do you think any of you could know what could cause this sort of thing?
 
Cable channels 95-99 occupy the same broadcast spectrum as part of the FM radio band, so if the cable system is leaky, FM stations will bleed through into the the cable service. Also, many pager or beeper services broadcast on the same frequencies as cable channels 18-20, I believe. Soem years ago, when I surscribed to good ole Adelphia, I had a problem with cable 19 that just would no go away, despite the continued efforts of the crack Adelphia technicians (they really did try hard) who admitted it was beeper interferrence.
 
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