finn@mojo.UUCP (Finn Markmanrud) (01/12/90)
For the past year or so, I've been subscribing to Video Review Magazine,
and in every issue there are lots of advertisements for so-called "Cable
TV Descramblers" and "Rental Movie Stabilizers" by Oak, Hamlin, Jerrold,
and more. Does anyone have any experience with these things, or know if
they work or not? I am most of all wondering what the "Descramblers" are
capable of descrambling. HBO, Cinemax etc. (i.e. "pay channels"), or just
ESPN, FOX, etc. ("basic service channels")?
Why does one need a rental movie stabilizer? Does it really help? I assume
that the device is mostly used for copying rental movies, something the
advertisers ofcourse state in their ads is highly illegal.
I have been contemplating buying my own cable box, since the one from the
cable company is at least 10 years old, and distorts the picture substan-
cially. I need a box, even though my TV is cable ready. I get about 12 of
36 channels w/o the box. Before I go shopping, I would like to know a little
more about these descramblers, and other TV/Cable gadgets not mentioned here.
--
+=====================+========================+=============================+
| Finn Markmanrud | finn@mojo.nec.com | "It can't happen here." |
| (508) 264 8668 | Boxboro, MA | F.Z. |
+=====================+========================+=============================+logajan@ns.network.com (John Logajan) (01/13/90)
In article <235@mojo.UUCP> finn@mojo.UUCP (Finn Markmanrud) writes: >Does anyone have any experience with these things, or know if >they work or not? I am most of all wondering what the "Descramblers" are >capable of descrambling. HBO, Cinemax etc. (i.e. "pay channels"), or just >ESPN, FOX, etc. ("basic service channels")? There are two functions needed in cable -converting- and -descrabling-. Some cable ready tv sets come with built in converters, this is due to the fact that cable uses all the radio frequencey space on the cable for TV signals, whereas airwave broadcast TV has large gaps devoted to other services. There is a small gap between ch4 and ch5 and a large gap between ch6 and ch7 and a huge gap between ch13 and ch14 (or is it 12 and 13?). The other tv channles 2-3, 7-13, and 14-83 are next to each other. So the converter usually converts the cable channels down to one broadcast channel (3 or 4) and you tune the converter rather than the tv. Pay services are usually scrambled, so in addition to a converter you need a descrambler. The typical descrambler is built inside of the converter but for some units you can get external descrablers. The type sold by the various "pirate" outfits usually use reconditioned converter/descrambler units salvaged from who knows where. I've often suspected that the cable equipment manufacturors secretly funnel these reconditioned units to the pirate outfits -- how else to explain the huge volume of units in the pirate inventory. Anyhow, the descrabler units DO WORK if you have the right type for your system (there are several systems around and they are not necessarily compatible so you have to make sure you get the right equipment.) Once you get the correct manufacturor type you should be able to view ALL channels. Several past Radio-Electronics magazine issues have discussed how descrambling is done, and they have give construction projects with complete plans. >that the device is mostly used for copying rental movies I am not very familiar with the latest rental movie protection techniques, but it used to be more popular. They would play around with the vertical sync timing such that a VCR trying to record with get wacked out. It takes longer for a VCR scanning head to adjust speed than the TV CRT. Unfortunately, it also takes longer for the VCR player heads to adjust so that method can cause problems in normal viewing -- and fell into disfavor -- I thought. There are moves afoot to do the same kind of vertical sync monkeying on cable channels that don't want you to be able to record. But the main force behind this is a company trying to sell its technology. The cable channels are pretty competitive, and few want to be the first to disallow VCR taping -- for fear of losing their customer base. So I don't see this happening anytime soon. -- - John Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428 - logajan@ns.network.com, john@logajan.mn.org, 612-424-4888, Fax 424-2853
jharkins@sagpd1.UUCP (Jim Harkins) (01/16/90)
In article <1990Jan13.005314.5145@ns.network.com> logajan@ns.network.com (John Logajan) writes:
-I am not very familiar with the latest rental movie protection techniques,
-but it used to be more popular. They would play around with the vertical
-sync timing such that a VCR trying to record with get wacked out. It
-takes longer for a VCR scanning head to adjust speed than the TV CRT.
-Unfortunately, it also takes longer for the VCR player heads to adjust
-so that method can cause problems in normal viewing -- and fell into
-disfavor -- I thought.
No, it's still there. Last summer I bought a friend a cheap VCR and on maybe
a fourth of the movies she rents the damned picture rolls every few minutes.
On my (expensive) VCR I don't have any problem. IMHO, a copy-protection
system that causes problems like this should be outlawed, or the VCR should be
clearly labeled "WARNING -- We know you are honest but the movie companies
think you are all thieves. This VCR may have problems showing some movies".
Of course, she never mentioned this problem to me and by the time I saw it
the thing was out of warranty. bah humbug.
jim
"Only dead fish go with the flow"paulm@ccicpg.UUCP (tmp Paul Moreau usenet acct) (01/17/90)
> For the past year or so, I've been subscribing to Video Review Magazine, > and in every issue there are lots of advertisements for so-called "Cable > TV Descramblers" and "Rental Movie Stabilizers" by Oak, Hamlin, Jerrold, > and more. Does anyone have any experience with these things, or know if > they work or not? I am most of all wondering what the "Descramblers" are > capable of descrambling. HBO, Cinemax etc. (i.e. "pay channels"), or just > ESPN, FOX, etc. ("basic service channels")? > Why does one need a rental movie stabilizer? Does it really help? I assume > that the device is mostly used for copying rental movies, something the > advertisers ofcourse state in their ads is highly illegal. > I have been contemplating buying my own cable box, since the one from the > cable company is at least 10 years old, and distorts the picture substan- > cially. I need a box, even though my TV is cable ready. I get about 12 of > 36 channels w/o the box. Before I go shopping, I would like to know a little > more about these descramblers, and other TV/Cable gadgets not mentioned here. > I'm not sure of the make but I have a rental movie stabilizer. Some rental movies, not all, use a system called MacroVision to copy protect thier movies. On most TVs this is no problem as long as the original tape is used. I believe the method involved is in modulating the amplitude of the horizontal sync pulses. The output of VCRs are not run through an AGC (Automatic Gain Control) circuit so the fluctuations have no efect. But the input of VCRs do go through an AGC. The AGC is sensitive to the change in Sync pulse amplitude and tries to keep a constant voltage level on the incomming signal. Varying the sync amplitude causes the AGC to clamp down on the signal causing the Video section 'which is not modulated' to be also cut down. This causes very noticable Contrast and briteness changes to occur on the copy. The stablizer, I believe, strip and condition the sync and then re-mix them with the video. Now this covers the 'copied tape' problem. The other problem as I said earlier is that the Macrovision doesn't bother 'Most' TVs with the original tape. However, the RCA XL-100 series of TVs are not included. Most decent TVs condition the Video sync pulses but it seems the RCA took a short cut and didn't condition them. This causes screen 'Jitter' and 'tearing' (SP) to happen. I know, my dad 'HAD' an RCA that he could no play any 'protected' tapes on. As far as the box being worth it, YOU BET! Well I hope this helped a little. --- .==========================================================. | ### ####### ### | N O R T H | /==============\ | | ### ### ### | A M E R I C A |< An STC Company >| | ### ####### ####### | (was CCI) | \==============/ | |----------------------------------------------------------| | UUCP: ...ccicpg!dl2!paulm | Paul L. Moreau | | or ...ccicpg!dl1!paulm | Diagnostics Software Eng. | | or ...ccicpg!paulm | Irvine, California | `==========================================================' California is a fine place to live -- if you happen to be an orange. -- Fred Allen