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Discussion Starter #1
I've just been thinking forward to transition. Here is a potential situation in the GTA:

WKBW rf38 virtual channel shows up as 7.1
WNGS rf7 virtual channel shows up as 67.1, 67.2, 67.3
WPXJ rf23 virtual channel shows up as 51.1, 51.2, 51.3
CJMT rf51 virtual channel shows up as 51.1
WNLO rf32 virtual channel shows up as 23.1

If I turn on my TV in Sept 2011, I'll have two 51.1 channels.

What happens in this circumstance?
 

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It all depends on CJMT's PSIP data. They could very easily change the data to "Bob's your uncle", and it won't matter to you. If CJMT is going to try and use 51.1 in the PSIP, then that is a good question on how the ATSC standard handles that sort of situation.
 

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During a past tropo event I picked up WEWS-DT 5.1. Pressing the up channel button on the remote brought up 5.1 CBC. So I had two 5.1 channels. That's on my Artec converter box.
 

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My tuners allow for the duplicate channel numbers sanyo,Panasonic,Samsung boxes but direct entering the number only brings gives you the one channel and the up and down key tunes the duplicate.I have seen it with tropo. reception.It would be nice to drop channel number re mapping.
 

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I'm guessing that CJMT won't have a virtual channel since that station really hasn't built-up much of a brand identity on its current channel position.

Just having two of the same virtual channel might be the best solution as long as it doesn't screw up people's PVRs.

If the conflicting virtual channels re-map to their real channels from their virtual channels, then you can see from my first post what a cascading series of conflicts would occur.
 

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yeap, as long as ur getting good signal from all of them, you won't miss a beat. Can get confusing for some tuners when the signal is marginal, on the threshold of being decoded properly. During tropo events I've see numerous duplicates and my tuners don't miss a beat.
 

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As mentioned, there is no specific "standard" with regards to virtual channel conflicts. It's up to the tuner itself to manage the "conflict".

My Sony Bravia tuner simply assigns another subchannel to the next channel on the same virtual channel. For example, the first channel is 5.1, and the next same channel will be 5.2.
 

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My Sharp Aquos tuner lists stations saved into memory by their virtual channel numbers only. It is able to save into memory multiple stations having different real channel numbers but shared real channel numbers, or overlapping real and virtual channel numbers, but only if they are saved into memory in a certain order. This assumes that the two stations cannot both be caught in a single channel scan because they are in different directions, necessitating rotating or switching antennas. My tuner has single scanning capability (but no additive channel scan that saves all stations from a previous scan) and also allows for manual channel entry using only the real (not virtual) channel numbers.

For your situation, if I wanted to save both WPXJ and CJMT into memory, I would have to enter in CJMT first (either by scanning or by manual real channel entry) because its real and virtual channel numbers are the same, while WPXJ's real and virtual channel numbers are different. So, I would point the antenna toward CJMT and either run a scan or manually enter the real channel number 51.1 with my remote. That would save CJMT into the station memory on virtual 51.1. Then, I would rotate the antenna toward WPXJ and manually enter in the real channel number 23.1 with my remote. That would save WPXJ as a second 51.1 entry (plus subchannels 51.2 and 51.3) in the memorized channel list. The order of the stations as listed in your channel memory would be two 51.1's (not sure of the order) followed by the 51.2 and 51.3 WPXJ subchannels.

If I tried to instead save WPXJ into memory first (either by an initial scan or by manual entry), my subsequent attempt to manually enter a 51.1 for CJMT would just tune the tuner to the already-saved WPXJ, making CJMT impossible to receive without first erasing WPXJ.

Similar situation for your WKBW and WNGS because they have overlapping real and virtual channel numbers. You'd have to manually enter in real 7.1 first with your remote, which would save WNGS as virtual 67.1, plus its subchannels as virtual 67.2 and 67.3. Then, you'd manually enter in real 38.1 with your remote, which would save WKBW as virtual 7.1. If you tried it in the reverse order by first entering in real 38.1 for WKBW, my tv's tuner would save WKBW into memory as virtual 7.1. Then, any subsequent attempt to enter in real 7.1 to save WNGS would just cause the tuner to tune to WKBW, so that WNGS could not be received at all.

To date, I have not found any way for my tv tuner to receive two different stations that share real channel numbers. I have two sets of these, in opposite directions from me. Also, because I have a few different sets of stations with overlapping real and virtual channel numbers, or shared virtual channel numbers, I chose to not do any scanning, but instead set up all my stations into memory by manually entering the real channel numbers in an order that would receive and save into memory all stations (except for the ones with the overlapping real channel numbers).

Hope this is helpful...
 

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gcd0865 thanks for that. Without getting into the workings of PSIP it is important to remember that the data streams from each of those stations contain unique identifiers, so while your tuner's User Interface seems to be pretty clumsly in the way it handles the virtual and real numbers, once you've got the channels entered and they are both lockable at the same time there is no worry of one's programming invading the other's. Given that, why your TV's manufacturer didn't design for allowing more than one real channel with the same number is beyond me.

PSIP has turned out to be a real rat's nest, and like a rat's nest you can keep cleaning it out of the shed but you'll never get rid of that stink. ;) The Mobile ATSC M/H standard attempts to address this kind of nonsense, but that's not much help in this case.
 

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To date, I have not found any way for my tv tuner to receive two different stations that share real channel numbers.
I've actually run into the same situation myself. PBS Detroit, which I often receive during tropo conditions, and PBS Buffalo, are both on real channel 43. My Sony Bravia won't create a separate entry for the Detroit station. But I can receive it by going to virtual channel 17.1 (Buffalo PBS). Strange, eh?
 

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As long as the real channel is different all my units handle multiple virtual channels without issue.
 

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I see an error in my previous post, where the first two sentences were supposed to read:

"My Sharp Aquos tuner lists stations saved into memory by their virtual channel numbers only. It is able to save into memory multiple stations having different real channel numbers but shared VIRTUAL channel numbers, or overlapping real and virtual channel numbers, but only if they are saved into memory in a certain order."

Sorry if this caused any confusion.

I'm not sure why my tuner cannot store into memory two different stations that share a real channel number. Perhaps since the tuner was designed to store stations in sequential order by their virtual channel number, there is some kind of priority assigned to the virtual number, such that the real channel number is essentially ignored. Otherwise, perhaps the designers simply missed the possibility of some people being located between two stations sharing a real channel number.
 

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Update for REAL channel number overlap

Hi All:

Previously, I advised about how my Sharp Aquos OTA tuner handles stations with overlapping real/real, real/virtual and virtual/virtual channel numbers for digital OTA stations. I have now learned something contrary to my previous understanding about how my tuner handles stations with overlapping REAL/REAL channel numbers that might be interesting to the group.

Specifically, I've just confirmed that, while my tuner is still not able to SAVE into memory more than one station with a given REAL channel number, I am able to SWAP a first station saved in memory with another station sharing the same REAL channel number, without doing a new channel scan or otherwise erasing all memorized stations.

To illustrate, I already had WLNS Real 36.1/Virtual 6.1 from Lansing, Michigan (due west of me) saved into memory from previous manual station entry. Upon rotating my antenna around to the southeast, I found that WFMJ Real 20.1/Virtual 21.1 from Youngstown, Ohio was coming in (from manual entry of REAL 20.1 via the remote). As a reminder from my previous post, I was only able to check for reception of WFMJ by manually entering in Real 20.1 because I had purposefully not previously programmed into memory the overlapping local Detroit station WMYD Real 21.1/Virtual 20.1.

Upon receiving WFMJ, I wondered if I could receive any other Youngstown stations. Several Youngstown stations cannot be received from my area simply because their REAL channels are identical to those for some of the local Detroit stations, so reception is simply blocked signal-wise. However, since WYTV Real 36.1/Virtual 33.1 shares a REAL channel with only WLNS Lansing, Michigan (which is 65 miles in almost the opposite direction), maybe WYTV could be received from my location.

Since I already had WLNS saved into memory under Real 36.1/Virtual 6.1, I thought I could not possibly receive WYTV unless I erased all saved stations from memory (by doing a new full scan with no antenna connected) and then (with the antenna re-connected) either performing a new scan or manually entering REAL channel 36.1 via the remote. However, just to check, I manually entered REAL 36.1 with the remote, but the tv's tuner instantly jumped to VIRTUAL 6.1 (looking for WLNS, which couldn't be received with the antenna pointed southeast). But when I entered in 36.1 a SECOND time with the remote, the tuner instantly tuned in WYTV on Real 36.1/Virtual 33.1.

Checking the tv's station memory list (which are stored only by VIRTUAL channel number and station call letters on my tv), I found that both previously-saved WLNS subchannels 6.1 and 6.2 have been removed from memory and all three subchannels for WYTV (33.1, 33.2 and 33.3) now appear in the memorized station listing. My tv automatically saves all subchannels for a given station into memory once any one subchannel is manually tuned.

I've done the same thing with WDCQ Real 15.1/Virtual 19.1 Bad Axe, Michigan and WEWS Real 15.1/Virtual 5.1 Cleveland, Ohio, swapping these stations in my memorized station listing. The secret (at least for how my tv's tuner acts) appears to be that, when an already-memorized station is entered manually via remote by its REAL channel number, it will search for the already-saved station (according to its corresponding VIRTUAL channel number) the first time. However, if the tuner cannot tune that first station (such as because the antenna is not aimed toward that first station), and you enter the same REAL channel number via the remote a SECOND time, it will either override or ignore its previously-known attachment to that first station's VIRTUAL channel number, and consider tuning any other/new available station having that same REAL channel number (regardless of its VIRTUAL channel number).

To the best of my knowledge, the same restrictions I previously mentioned regarding overlapping real/virtual and virtual/virtual channel numbers still exist, requiring me to tune stations in certain orders to avoid foreclosing future ability to tune other overlapping stations. Nevertheless, I found this discovery (and the removal of a previously understood tuning limitation) interesting. Hope others find it interesting as well. Wondering if others' tv tuners act the same way. Sorry for the long post to explain this (hopefully it's clear to everyone)...
 

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I have an RCA ATSC television in one room, and it does not handle conflicts well. Depending on the position of my antenna, I can receive either WLNS Lansing (RF36, PSIP 6.1) or WUPW Toledo (RF46, PSIP 36.1). Both will not stay in memory, and you can't manually add channels. You can manually tune, but when I punch in 36 it goes to 6.1 . When I punch in 46 it goes to 36.1 for a second then goes blank! I've never seen any other TV or receiver do this.
 
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