View Full Version : 4-way cable splitter - does it need amplification?
I have one wall socket and I need four devices -
1 - cable modem
2 - other TV
3 - PVR250
4 - reserve/2nd PVR250
The cable TV quality sucks even if I connect a TV to the wall socket directly. (Depending on the channel, though, some are fabulous.)
On an analog TV it does not seem to matter so much, but a noisy picture really seems to confuse the PVR250.
Q: How much loss does a passive 4 way splitter incur? Is it worth to get an active device with amplification?
I know the amplifier is not improving the signal over the level it has available from the wall plug. However I do want to avoid further loss in quality.
My setup is this:
1->2 Splitter with 1 connection to Cable Modem, the other connection to...
1->2 Splitter/Amplifier 10dB boost per output (20dB total)
Side A goes to a 1->2 Splitter send to my two PVR-250s
Side B goes to a 1->4 Splitter for my TV, ReplayTV, and VCR
(4th connection is terminated)
Prior to amplification, I had a 1->2 Splitter where the Amp goes.
My reception on the PVR-250s was not good. VHF channels at the
low end (e.g. Ch. 2) and UHF channels at the high end (e.g. Ch. 72)
were fuzzy, lacked color, and had diagonal interference lines.
After amplification, both extreme ends were greatly improved.
Turning DOWN the Saturation level on the PVR-250 also improved
the capture. I now can even watch fast-moving sports (e.g. NBA)
via the PVR-250s...
A small but very beneficial investment for me at least...
05-06-2003, 12:54 AM
If you buy a good splitter and use good cables you'll loose about 7.5db in signal strength wenn using a 4 splitter.
You also have to make sure you have the cable connecters/plugs properly connected. I worked for a cable company and saw that 95 % of bad reception was due to badly connected cables (many have only the core connected, not the metal casing (don't know the english word for that))
A normal signal (at least in the Netherlands but i guess this about the same everywhere) has a signal strength of 70 db.
A good tv can work with about 55 db but vcr's and capture card need about 60-65.
So in the ideal case wenn the incomming signal is good you don't need to amplify.
You could gain about 2 db if you would split the signal first with a 3 splitter (5.5 db loss in signal), so 2 for the 2 pvr's and on the other connect a 2 splitter for the modem / tv. But this will probably not really help.
But as you allready mentioned, the signal is allready very bad wenn it comes in, so the only solution is to buy a good amplifier.
(hmm, quite a long stroy to come to such a simple conclusion )
Thanks - that was exactly what I needed to know.
Are there any special requirements for the cable modem? (which needs to talk back upstream)
05-07-2003, 12:37 AM
figure out what frequency it is using and see if the amplifier and splitter don't filter this (mostly they don't but check to be sure)
I installed the Amplifier "downstream" from a 1->2 Splitter. One connection to the CableModem (i.e. "un-amplified") and one to the Amplifier. I see no benefit in Amplifying the signal sent to the CableModem... This nicely avoided the question :-)
05-18-2003, 07:04 PM
<-- poor college student. What's a good amp/splitter to buy? And where?
partsexpress.com has been an inexpensive source for other items for me.
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