DCFluX wrote: > It is 75 Ohm cable, Paticualrly RG-6 Plenum which has approx 1dB of > Tilt per Octave at 100'. Maximum power is +25dBmV. Intersted in > attenuating the lower channels more than the upper ones, and I will > follow it with an amp on each floor after it is compensated.
The device you are looking for is simply called a forward equalizer. In CATV, the equalizer compensates for cable tilt induced ahead of an amplifier. If the amplifier that has been deployed has a "Tilt" or "Slope" control, turn it so the lower channels are running out lower. This is called positive tilt. Commonly, 6 to 12 dB of tilt is added at each amplifier location. Even with the application of positive tilt at each amplifier, it is not uncommon that the signal at the back of the set is "reverse tilted" to some degree. The sweet spot for most sets is 0 to 8 dB across the board, but the lower channels are typically much higher due to cable tilt. You should strive for no less than 0 dB on the high channel, and no more than 20 dB on any other; measured at the back of the set. > Some genius company, that is used to installing security systems in > Las Vegas ran the cable in this building and thought that a single > amplifier would cover the entire building. Which is scary because the > company had the $4000 piece of test equipment to tell them how screwed > up their install was. That piece might have been a Wavetek Stealth 3SR (older) or Acterna SDA-5000 (newer vintage of same piece). My SDA has all of the digital and return (reverse) capabilities and also has transmit capabilities for sweep or loopback sweep, and was $8200.00 3 years ago, as the base cost is around $4K. > Up on the third floor I measured 50dB of tilt between Ch.2 and Ch.77 50 dB of tilt indicates something very wrong. Here are some links to help: <http://www.shol.com/kuggie/cttip/padsandeqs.html> <http://www.cabl.com/restaurant/formula.html#tilteq> <http://www.tinlee.com/TV_Signal_Distibution.htm#Line%20Equalizers%20(Tilt%20Attenuators)> <http://www.acterna.com/global/products/descriptions/SDA-5000/> Good luck, Kevin Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
