Those of you involved with domestic TV systems in any way may find this story a familiar one. Make yourselves comfortable......
A guy I've done work for before seems to have gotten into whole-house TV in a big way. A couple of years ago I installed a satellite system for him using an older analog receiver and dish that he'd been given. Since then, he's swapped over to a digital receiver and run his own distribution system around the house. The feeder from the regular UHF roof antenna was looped through the satellite unit, then through the VCR, back up into the attic to a 4-way distribution amplifier, and from there back down to the main TV in the living room and to three other sets around the house. He also had direct SCART (audio-video) connections between the satellite/VCR/main TV.
All normal broadcast TV in the U.K. is on UHF. The four main networks on the local transmitter are up near the top end of the band on channels 55, 59, 62, and 65. By the time I looked at this set-up, the four off-air UHF signals viewed directly on any of the sets around the house were poor, to say the least. Apparently it hadn't bothered him too much, as all are available on the satellite anyway, so they only watched one direct if the satellite receiver was being used to watch/record something else at the same time. They could also switch the VCR to one of the networks and watch the VCR output around the the house, which resulted in much improved picture quality. So the set-up was far from perfect, but it had satisfied them for a while.
Now, came the problem. He'd gone out and bought a new digital terrestrial receiver which he wanted to add to the system. This needed a feed from the UHF roof antenna, and obviously its RF output would also need to be distributed to everything so it was yet another
box for the line to loop through.
The result was that the four analog UHF signals were now varying in quality from very poor to terrible when viewed directly. He'd connected the new digi-box to the main TV with a SCART lead, but had run into big problems with trying to tune in the new signal on that set's tuner and around the rest of the house. He'd also got a pre-amplifier to insert in the attic on the incoming feeder from the antenna to try to boost the signals. That had worked (I should hope so, as it provided 20dB gain!) and the four analog UHF signals were now excellent throughout the house, but the satellite signal now had bad patterning. It was at this point he became totally confused and called yours truly (probably at the behest of his wife, who didn't understand why he wanted yet another box anyway
It's already too late to cut a long story short, but I found that the reason he couldn't properly tune in the signal from the new digi-box was that its output was set to channel 36. The VCR was already feeding its signal out on ch. 35. Retuning the digi-box output to a clear spot at ch. 48 fixed that.
The patterning on the satellite signal around the house was caused by the now very strong analog broadcast signals coming down from the attic. The digital satellite receiver he'd acquired had its RF output tuned to channel 68, and with the now 20dB stronger off-air signals the distribution amplifier in the attic was cross-modulating and throwing out all sorts of spurious signals across the band. One of them happened to be right on ch. 68. I retuned the satellite output down to the bottom of the band at ch. 21, and also found several bad joints at coax plugs. Fixing them resulted in good picture from the satellite receiver throughout the house.
Now one of the problems this guy faced with setting up all this equipment is the complicated on-screen menus used on all this equipment. Obviously we had to go around the house and re-tune every TV to the new frequencies, but every set was different, and a couple of them had such complex menus (and no instruction books!) that it took me at least ten minutes on each to figure out how to even get into the tuning menus.
The digital satellite box has a whole batch of set-up menus, but anyone looking for a way to change the RF output channel would be out of luck. You can go through every menu you can see and not find it, because it's on a hidden "installer" menu which isn't even mentioned in the user's manual. You just have to know
to press 0, 1, Select. I can see how they might want to prevent Mr. Average from messing around with the LNB IF offset, 22kHz switching signal, etc., but why hide the option to change the output channel? More and more people are getting complex set-ups like this these days, so they're bound to need to change the output from the default at some point to avoid clashes.
Anyway, both the lady and gentleman of the house were satisfied with the eventual quality of all pictures, and I left them with consistent settings on all TVs: 1 thru 4 = normal networks, 7 = digital terrestrial, 8 = VCR, 9 = satellite.
I'm not sure they've quite mastered how to switch to direct A-V inputs on the main TV in the living room or quite figured out just exactly what combinations of channels they can watch and/or record at the same time, so I wouldn't be surprised to get another call sometime soon.
Did I mention that he also bought a new widescreen TV for the living room? I'll save my comments on that for next time!
[This message has been edited by pauluk (edited 07-31-2003).]