Hi - on one of the DTVPal threads, I was commenting on how TVGOS worked, and someone else cited a quotation from January that I had seen before, from a Gemstar guy who said that the RCA cecb passed the TVGOS data from a digital station to its converted output, and that most other cecbs would probably do so, too
I commented that I should try the DS9950 that my housemate just got.
Well, over the last three days, I hooked up my housemate's 9950 next to my high-def setup, which includes an LG3410a digital receiver/high-def recorder that gets its TVGOS data from analog PBS locally. I set the 9950 to channel 5-1, the local CBS station, which has been reported to be carrying the TVGOS data currently (cf. the Sony 250/500 thread, and the associated operational manual from spiffy http://www.spiffspace.com/sonydvr.html#Section2 .
1 - For the first night, I joined the 9950's output with (another branch of) the signal from the antenna, and I turned off ALL the analog channels in the 3410a's setup AND in its TV Guide screen, but TURNED on channel 3 in both. In real life, channel 3 is the analog NBC station from Sacramento that isn't received at all in Berkeley (100 miles away and through hills...).
When I looked to see what I was receiving with this setup, on channel 3 I was getting a pretty clear analog version of CBS 5.1...it seemed slightly snowy, but I checked that cc (closed captioning) worked, which confirmed that the vbi data was coming through from the DS9950's conversion. I could, of course, also get all the local digital channels, and hmm...I am puzzled over what I checked about the normal analog channels at that time...
I left the 3410a on channel 3, turned it off, and checked the next AM to see what had happened. I found it had gotten TVGOS data, but when I checked the service screen that identifies the host channel for TVGOS, it still said it was channel 9, the local PBS station...
2 - for the second night, I removed the branch from the antenna from the 3410a's input, leaving only the rf from the 9950. This time, I checked what I could see via the 3410a more carefully, finding that I could still see very poor signal from the lower analog channels, except for channel 3 (the converted channel), which came in with a very nice picture, but for channel 9 (PBS) I was getting a snowy picture but good sound, and - as I went to the UHF channels - the picture got quite good. I also found I was still getting all the digital channels perfectly...I didn't try to figure out why this was. I did check the relatively poor channel 9 reception to see if cc was coming across, and it wasn't, indicating that vbi wasn't being received (or at least not well). I set the 3410a on channel 3 and left it on overnight again.
When I checked the next day, the 3410a had NOT received TVGOS listings overnight. I checked the service menu for the host channel, and is reported "0", which I take to mean it didn't find a TVGOS host overnight.
3 - I removed the antenna branch cable that HAD been joined into the 3410a for the first night's test, but that I had left lying behind the 3410a...I was worried the unit might be picking something up from it. I ran night 3 in the same configuration as 2, i.e., with input only from the 9950 and with the 3410a tuned to channel 3 before turning it off. This time I got PARTIAL listings, and the service menu now identified channel 9 (the PBS station) as the host channel.
Because I was still puzzled over the low quality reception of the analog channels, I did the test I should have done during the previous day: I removed the cable from the 9950 to the 3410a, and ALL reception disappeared, indicating that the low-quality analog and good digital was coming via this cable. With the cable connected, I then hit the analog pass-through button on the 9950's remote back and forth and found that I always received digital, but with pass-through off I received channel 3 (the conversion from 5.1) clearly, and the real analog channels poorly. With pass-through on, I did not receive channel 3, but received everything else well.
I concluded at first that this means that in the 9950's digital conversion mode, there is just a filter against the UHF channels, which is removed in pass-through mode.
But I just realized that another alternative is that it is the CABLE connecting the 9950 and the 3410a that is providing these puzzling signals. So I just tried the 3410a with just that piece of cable as the antenna, and found that I did receive some signal, but it was generally POORER for analog than I was receiving from the 9950 with pass-through OFF, and I was only receiving THREE digital channels with just the cable, rather than all of them. So the 9950 seems to be passing higher frequencies reasonably well even if pass-through is off. Of course, the fact that the cable has a device hanging on the other end of it may make it a better antenna....I don't know about that.
And I have to conclude that my test of TVGOS reception is inconclusive because the data from PBS analog was still available. UGH all around...I'll have to wait for my DTVPal; but even then, the availability of the PBS data may make any current test fruitless...hmm...seems like I need a sharp high-pass filter for the antenna signal going INTO the cecb...
I commented that I should try the DS9950 that my housemate just got.
Well, over the last three days, I hooked up my housemate's 9950 next to my high-def setup, which includes an LG3410a digital receiver/high-def recorder that gets its TVGOS data from analog PBS locally. I set the 9950 to channel 5-1, the local CBS station, which has been reported to be carrying the TVGOS data currently (cf. the Sony 250/500 thread, and the associated operational manual from spiffy http://www.spiffspace.com/sonydvr.html#Section2 .
1 - For the first night, I joined the 9950's output with (another branch of) the signal from the antenna, and I turned off ALL the analog channels in the 3410a's setup AND in its TV Guide screen, but TURNED on channel 3 in both. In real life, channel 3 is the analog NBC station from Sacramento that isn't received at all in Berkeley (100 miles away and through hills...).
When I looked to see what I was receiving with this setup, on channel 3 I was getting a pretty clear analog version of CBS 5.1...it seemed slightly snowy, but I checked that cc (closed captioning) worked, which confirmed that the vbi data was coming through from the DS9950's conversion. I could, of course, also get all the local digital channels, and hmm...I am puzzled over what I checked about the normal analog channels at that time...
I left the 3410a on channel 3, turned it off, and checked the next AM to see what had happened. I found it had gotten TVGOS data, but when I checked the service screen that identifies the host channel for TVGOS, it still said it was channel 9, the local PBS station...
2 - for the second night, I removed the branch from the antenna from the 3410a's input, leaving only the rf from the 9950. This time, I checked what I could see via the 3410a more carefully, finding that I could still see very poor signal from the lower analog channels, except for channel 3 (the converted channel), which came in with a very nice picture, but for channel 9 (PBS) I was getting a snowy picture but good sound, and - as I went to the UHF channels - the picture got quite good. I also found I was still getting all the digital channels perfectly...I didn't try to figure out why this was. I did check the relatively poor channel 9 reception to see if cc was coming across, and it wasn't, indicating that vbi wasn't being received (or at least not well). I set the 3410a on channel 3 and left it on overnight again.
When I checked the next day, the 3410a had NOT received TVGOS listings overnight. I checked the service menu for the host channel, and is reported "0", which I take to mean it didn't find a TVGOS host overnight.
3 - I removed the antenna branch cable that HAD been joined into the 3410a for the first night's test, but that I had left lying behind the 3410a...I was worried the unit might be picking something up from it. I ran night 3 in the same configuration as 2, i.e., with input only from the 9950 and with the 3410a tuned to channel 3 before turning it off. This time I got PARTIAL listings, and the service menu now identified channel 9 (the PBS station) as the host channel.
Because I was still puzzled over the low quality reception of the analog channels, I did the test I should have done during the previous day: I removed the cable from the 9950 to the 3410a, and ALL reception disappeared, indicating that the low-quality analog and good digital was coming via this cable. With the cable connected, I then hit the analog pass-through button on the 9950's remote back and forth and found that I always received digital, but with pass-through off I received channel 3 (the conversion from 5.1) clearly, and the real analog channels poorly. With pass-through on, I did not receive channel 3, but received everything else well.
I concluded at first that this means that in the 9950's digital conversion mode, there is just a filter against the UHF channels, which is removed in pass-through mode.
But I just realized that another alternative is that it is the CABLE connecting the 9950 and the 3410a that is providing these puzzling signals. So I just tried the 3410a with just that piece of cable as the antenna, and found that I did receive some signal, but it was generally POORER for analog than I was receiving from the 9950 with pass-through OFF, and I was only receiving THREE digital channels with just the cable, rather than all of them. So the 9950 seems to be passing higher frequencies reasonably well even if pass-through is off. Of course, the fact that the cable has a device hanging on the other end of it may make it a better antenna....I don't know about that.
And I have to conclude that my test of TVGOS reception is inconclusive because the data from PBS analog was still available. UGH all around...I'll have to wait for my DTVPal; but even then, the availability of the PBS data may make any current test fruitless...hmm...seems like I need a sharp high-pass filter for the antenna signal going INTO the cecb...