wales@ucla-cs.UUCP (01/25/85)
I have cable TV in my apartment. I run the cable through a splitter;
one side goes to the channel selector supplied by the cable company,
while the other side goes to my VCR. The two outputs in turn run
through a two-way coaxial switch ("A-B switch") to my TV set -- which,
of course, allows me to watch material either from the VCR or directly
from the cable, and/or to record one program while watching another.
My question regards my splitter, which is a strictly passive unit with
one input and two outputs.
(1) Can a setup like mine be expected to degrade cable reception --
either my own or anyone else's? (I can't see any degradation in
signal quality, but maybe I'm just not picky enough.)
(2) If I were to do something extravagant like get a second VCR, and
wanted to split the incoming signal THREE ways, would problems start
arising that I don't currently find with my two-way split?
(3) Are there more sophisticated splitters available which would act
just like a single load to the incoming cable? If so, where should
I go looking for them, and about how much should I expect to spend?
(I would assume that such a creature would be a broadband amplifier
with multiple outputs -- and, since broadband amplifiers are tricky
to make work well, it would probably be expensive.)
--
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Rich Wales
University of California, Los Angeles (UCLA)
Computer Science Department
3531 Boelter Hall
Los Angeles, California 90024 // USA
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Phone: (213) 825-5683 // +1 213 825 5683
ARPANET: wales@UCLA-LOCUS.ARPA
UUCP: ...!{cepu,ihnp4,trwspp,ucbvax}!ucla-cs!wales
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-parnass@ihu1h.UUCP (Bob Parnass, AJ9S) (01/27/85)
> I have cable TV in my apartment. I run the cable through a splitter;.... > ...My question regards my splitter, which is a strictly passive unit with > one input and two outputs. > > (1) Can a setup like mine be expected to degrade cable reception -- > either my own or anyone else's? (I can't see any degradation in > signal quality, but maybe I'm just not picky enough.) Splitters introduce loss. In a theoretically ideal 2-way splitter, the most signal that a TV could get is only 1/2 what it could get without a splitter. This shouldn't be surprising, as one rarely gets something for nothing. Since there is no such thing as an ideal splitter, even more loss is introduced. However, if the original signal is strong enough, you won't notice a loss. > (2) If I were to do something extravagant like get a second VCR, and > wanted to split the incoming signal THREE ways, would problems start > arising that I don't currently find with my two-way split? The real danger, as I see it, is one of interference. There is a potential interference problem anytime one introduces a new element between the cable company's cable and a receiving appliance. Signal egress from the additional connections (and/or poor quality cable) is radiated. This can and has caused interference to devices not subscribing to the cable service. In a recent case in Westmont (IL) a subscriber used his own patch cable to connect the TV. The resulting signal leakage interfered with other TV's and VCR's in the vicinity. If you do use a splitter, remember to terminate any unused ports with the appropriate (75 ohm resistive) load. > (3) Are there more sophisticated splitters available which would act > just like a single load to the incoming cable? If so, where should > I go looking for them, and about how much should I expect to spend? > (I would assume that such a creature would be a broadband amplifier > with multiple outputs -- and, since broadband amplifiers are tricky > to make work well, it would probably be expensive.) > Rich Wales > University of California, Los Angeles (UCLA) Yes, you're speaking of an amplifier. Broadband amplifiers are, as the name implies, unselective. If a broadband amplifier has enough gain to make a big difference, it's likely that the amp will be susceptible to interference from other transmitters (like paging, CB, taxis, etc.). This problem is acute in urban areas. More expensive amplifiers avoid this problem through the use of tuned circuits optimized for TV frequencies. Since many cable companies translate TV signals to non-TV frequencies, this type of amplifier may not be applicable to your situation. Whatever you do, my advice is to "keep it simple." Plug and unplug cables rather than using consumer grade video switches. Use a splitter only when concurrent reception is necessary. -- =============================================================================== Bob Parnass, Bell Telephone Laboratories - ihnp4!ihu1h!parnass - (312)979-5414
ron@brl-tgr.ARPA (Ron Natalie <ron>) (02/01/85)
My cable company used the same 99c splitter that the local video store sells so I don't suppose there are any real technical problems here. -Ron