david@bragvax.UUCP (David DiGiacomo) (12/18/84)
In article <469@vortex.UUCP> lauren@vortex.UUCP (Lauren Weinstein) writes: >The satellite carrier has told me that if someone honestly thought >that they could manufacture demods/decoders and have the end-user >price be under $500, while meeting the specs necessary for broadcast, >cable company, and U.L. acceptance, they'd love it! And so would I. >In that case, I'm sure they'd be happy to make the specifications >available to a legit party. On the other hand, I'm pretty sure they >would not be happy to go tossing out their keys to their system, >which would go far toward compromising other, very expensive >services, just so that a few people could try build homemade >decoders and get transmissions for free. I can't blame them, either. OK, that settles the issue. Given these constraints I don't know how to produce low-cost decoders, and I retract my original statements. I'm very disappointed, since I don't think I will be able to take direct advantage of Lauren's system in the foreseeable future. My experience is limited, but I really don't know of many corporate environments where the required expenses will be justifiable. (If I'm wrong, please tell me where to send my resume (or have I been black-balled by now?)) I still don't understand the emphasis on the "professional" nature of the decoding equipment. (Isn't all of Usenet a massive kluge? Why did Lauren write his own UUCP instead of buying a professionally written UUCP package which met UUCP industry criteria?) I don't recommend that people build their own cable converters (analogous to modems in telephone Usenet), but what's wrong with a little healthy experimentation in the rest of the system? Appendix A: My right/privilege to kvetch (not strictly relevant). A couple of people have asked, "what have *you* done for the net?" -- a fair question. I have invested hundreds of hours in installing and maintaining (especially maintaining -- rn bug #29 indeed!) modems, uucp, and news at our site, in addition to time spent worrying about the phone bills. I didn't just sit down one day and type "vnews"! (I have also volunteered for the "Usenet Project" although nothing has happened yet.) I know that many others have contributed as much, or much more, and I hope to do something original as soon as I install 20 more patches, test the new postnews, integrate pathalias into rn, etc. etc. Until then, is my personal commitment worth anything? Can I have a flamage allowance for every patch I install? Appendix B: My conceptual low-cost semi-kluge decoder, now moot. 1. Cable converter: May be required depending on which channel WTBS is on, what you do about #2, etc. Your cable company may well require you to rent from them, otherwise you can get by with a "block converter" for about $30; real converters are quite a bit cheaper here than Lauren's quotes, especially if you're willing to settle for used/surplus (why not?). 2. Tuner: Buy a low-end TV set and bring out video & sync. It may be cheaper to buy a non-isolated set and an isolation transformer (or a set of optoisolators if you're adventurous), or you could just get a 12V set and a power supply. The advantage of using a TV is that you don't need sophisticated auto-tuning -- just twist the knob and watch the screen. Even cheap TV's have reasonable AFT, but maybe you would have to touch it up every few weeks. (I don't understand why cabletext tuning should be particularly different or delicate; the spectrum of a TV signal is pretty well nailed down whether cabletext is present or not.) The required modification of the TV is the weakest part of the scheme; I think there are alternatives available from pirate pay decoder technology, but I don't know the details (or condone knowledge of same!). 3. Decoder: I really doubt that custom chips are required or even desirable. At the low bit rates Lauren is proposing you could probably digitize the lines of interest and decode them during the rest of the frame with a common micro. However, I'll indulge myself and assume that the signal could be mostly decoded in real-time by a small collection of MSI/fuse logic etc. Physical implementation is a small board that plugs into #4. A couple of cables connect #2 to #3. 4. Computer interface: This is the easiest part -- just use an appliance computer (Radio Shack Color Computer, Commodore 16 etc.). If you do the hard part of the video decoding in hardware and stick a UART on the decoder board, the control software shouldn't be too difficult (about 1% of the complexity of inews, I'd guess). Note that the TV set and the computer are already UL listed, FCC certified etc. (at least until you hack them up), and the actual decoder doesn't come near power lines or RF. Also, the only item that would have to be sold is the decoder, probably as a kit. -- David DiGiacomo, BRAG Systems Inc., San Mateo CA (415) 342-3963 (...decvax!ucbvax!hplabs!bragvax!david)
dmmartindale@watcgl.UUCP (Dave Martindale) (12/19/84)
> but I really don't know of many corporate environments where > the required expenses will be justifiable. It is often possible to justify spending money on something on the grounds that it will be cheaper in the long run. That is the whole point of the satellite distribution project. > > I still don't understand the emphasis on the "professional" nature of > the decoding equipment. (Isn't all of Usenet a massive kluge? Why did > Lauren write his own UUCP instead of buying a professionally written > UUCP package which met UUCP industry criteria?) I suspect that Lauren wrote his own uucp because you can't get sources to the one owned by AT&T without spending over $40000, which is clearly not an option for most microcomputer owners. And I expect that, since Lauren intends to sell it, it will be professional-quality software when it is released. (Besides, it wouldn't be too difficult to make its quality better than that of the AT&T uucp that most people have.) However, the point of having "professional" equipment is that the stuff needs to work reliably. $500 is what it costs my employer for about 3 days of my time. It's pretty easy to waste more than 3 days trying to debug someone's flakey decoder, particularly if you don't have in-house hardware expertise. And I certainly can't build a useable piece of equipment myself in 3 days. > > Appendix A: My right/privilege to kvetch (not strictly relevant). > > A couple of people have asked, "what have *you* done for the net?" -- a > fair question. I have invested hundreds of hours in installing and > maintaining (especially maintaining -- rn bug #29 indeed!) modems, uucp, > and news at our site, in addition to time spent worrying about the phone > bills. I didn't just sit down one day and type "vnews"! (I have also > volunteered for the "Usenet Project" although nothing has happened yet.) > > I know that many others have contributed as much, or much more, and I > hope to do something original as soon as I install 20 more patches, test > the new postnews, integrate pathalias into rn, etc. etc. Until then, is > my personal commitment worth anything? Can I have a flamage allowance > for every patch I install? In a word, no. I've been involved in supporting USENET software at Waterloo for more than three years now. I just finished (last night) installing 2.10.2 news and rn on 11 machines. (Other people did do some of the installing of bug fixes). By your standards, I should have a very large "flamage allowance" accumulated. But flaming is seldom constructive, and for the most part just wastes the readers' time. Constructive criticism and comments are useful, but flames are not. So I generally restrict my flaming to replies to other flames. (And your initial reaction to Lauren's posting was definitely not "constructive criticism".) Dave Martindale