Question on splitting cable signals....

My cable TV reception is "OK" but I am thinking of ways to reduce signal loss and improve the picture if possible.

- I have about 6 TV's in my house.... 3 on the main living floor, and 3 in the upper bedrooms.

- My cable comes in the basement, and is split 4 ways, with one going to the upstairs.

- The upstairs lead is split again 3 ways for the bedrooms.

In theory, would it be better to split the incoming siganl 6 ways in the basement, and run 3 independant cables to each bedroom?

What about in practice? Would 1 less slpit in the chain improve things?

Reply to
Bill
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Most splitters have db loss printed right on them. Hook the shortest run to the hightest loss on the splitter. You might think about getting an amp to jack up the dB's first. Just don't put the amp where there is little or no signal or you will just be amplifying noise. Get a good amp, cheap ones just make it worse. Its always best to have home runs to each TV but thats not always feasible. Also make sure if your splitting a signal your not splitting it on the high db loss side of the splitter.

Good Luck, Rich

Reply to
EvoDawg

You could use a directional tap after an amplifier in the basement, feed the 3 sets from there and use your single feed for a signal to the upstairs with another directional tap or splitter for the rooms..

Just like real CATV - there is not a 16 way splitter at every corner >My cable TV reception is "OK" but I am thinking of ways to reduce signal

Reply to
DCT Dictator

Speaking of amps ..... A couple of years ago we had 5 TV's and an amp, gemini I think. We were eating dinner when we heard a loud beep, beep, beep coming from outside. There was a Comcast cable truck outside. The worker rang our bell. He said he detected an illegal condition that needed to be resolved. If we refused, service would be stopped. We let him in. He said that our amp was in violation and had to be removed. We complied and he went away. The reason he gave was that it interfered with aircraft, believe it or not. We never hooked it back up. It was very scary to have somebody pull up outside and "scan" our premisis. Makes you wonder what else they have.

Reply to
Sasal Suzi

Thepry and practice will be the same, as splitters are passive devices and the cable lengths will always come into play, as the distances will stay the same.

Each split is a 3.5 dB loss. A 4-way splitter is 3 2-ways in one enclosure (it splits once, then each split is split again) so you get a loss of -7dB on each of the 4 outputs. Finally, a 3-way (what it sounds like you have upstairs) is TWO 2-ways in one enclosure. It splits once and then ONE of those legs is split again, so your 3 outputs are not all equal, you have a "low loss out" (-3.5 dB) and two "high loss outs" (-7dB)

Yes, split everything at a convenient spot in the basement. Keep the existing 4-way that you currently have 1st in line, use three of those outputs and run them to the 3 sets farthest away from the split (your upper level rooms). The last output of the 4-way becomes the input to the 3-way that used to be upstairs, you can reuse it in the basement. Again, use the low loss leg to feed the TV farthest away from the split, and the two high loss outs will feed the TV's closest to the splitter.

If you count "splits in line between source and set" This is your current setup:

Downstairs 1: 2 Downstairs 2: 2 Downstairs 3: 2 Upstairs 1: 3 (low loss leg of 3-way) Upstairs 2: 4 Upstairs 3: 4 ...and this would be the new setup:

Downstairs 1: 3 (low loss leg of 3-way) Downstairs 2: 4 Downstairs 3: 4 Upstairs 1: 2 Upstairs 2: 2 Upstairs 3: 2

...same signal, just distributed better, getting more to the distant locations. HTH.

Reply to
I-zheet M'drurz

Have you talked to the cable company? I was pleasantly surprised a few years ago when I found that regulations changed. I pair for cable for one set and split it for three others, just like you have done. Definite reception loss, but better than paying for cable for each.

Some years later, they no longer charged for additional sets. The cable company came out and wired each one for a modest fee (10 or 15 bucks each) and reception is now perfect for all of them. NO splitters, no amps, no fuzzy pictures. Ed snipped-for-privacy@snet.net

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Reply to
Edwin Pawlowski

that's BS. they don't want you getting different TVs in your house without paying extra.

A coax cable is a shielded transmission line, it's got the neutral wrapped around the inner conductor and it shouldn't radiate anything, certainly not enough to reach airplanes. while a really bad amplifier could leak out RF, at 100MHz the wavelength is about 3 meters and an antenna must be at least 1.5 meters. I don't think the amp could work as a good antenna for the cable frequencies. maybe someone in front of your house could detect some leaks but not an airplane 10Km above.

it's more likely that the amp was cheap and it did create interference on their own network, or that they simply wanted you to pay extra.

Reply to
j j

It is basically a radio, your amplifier was emitting signals, IE broadcasting, and he was able to pick it up, with a more sensitive receiver than TV or radios.

The frequencies used by air craft, and police are right above the FM band (what would be 109-120 on the dial or so), which is between channels 6 and 7 in the TV spectrum.

So yes, a bad TV antenna product can cause problems with public safety.

Reply to
John Hines

Your amp was leaking RF, and the tech was picking it up with a RF leak detector. All cable companies are required by the FCC to conduct these test and fix any leakage. The leaks can interfear with the public safety, Police and Fire comm. and Airline communications. If the FCC was to have found the leak the Cable Company in question could have been fined. That was the only reason he came to the house and asked you to remove it. He could careless how many outlets you had installed in the house. Techs don't usually give to craps about outlets and charges not being collected because they're highly underpaid and overworked.

I should know I have been in the cable business for 25 years and just recently said good riddance to it. I owned a cable construction business and probably placed 100 of thousands of miles of cable up until some idiot cable inspector (Charter) working in cable for a year told me I was doing it wrong. That was the last straw. I retired from it and am happily doing home improvement work. Anyone want to buy a couple of T-40c's

Rich

Reply to
EvoDawg

yes, but there's no antenna in an amplifier. let's say the amp is 10 cm long, if there's a 10cm trace on the PCB it could radiate at 1.5Ghz, not 100MHz. I can see how someone outide your house can pick up stray emissions, but I don't see how these emissions would reach an aircraft 10Km above.

Reply to
j j

Just thought I would mention, if you buy splitter at Radio Shack, the gold ones indeed have better specs than then cheaper ones.

going to the

Reply to
Art Begun

Uh, the line cord on that amp was probably a bit longer than 10 cm, huh?

If the manufacturer didn't give a s**te about keeping the rf leakage down, then the amp could have been lighting up the house's whole electrical distribution system with rf. Odds are that's what the cable company picked up.

Now do you "see why". (Ducking...)

You've undoubtendly noticed labels on all sorts of electronic equipment stating that they comply with certain FCC rules with regards to rf leakage. Those "thick lumps" you often see on cables coming out of computer monitors are ferrite chokes, used to block rf currents from going any further.

Just my .02

Happy New Year,

Jeff

Reply to
Jeff Wisnia

If you do buy an amp, make sure you get one rated to amplify signals up to at least 900 Mhz, don't let someone stick you with an "old stock" amp which may only work up to 300 Mhz. You'll lose the higher channels with one of the old ones. (DAMHIKT)

Likewise with any cable you get, make sure it's rated for 900 Mhz too.

Happy New Year,

Jeff

EvoDawg wrote:

Reply to
Jeff Wisnia

Reminds me of England not so many years ago when folks had to pay an annual license fee/tax for each TV in a home, even though the signals they received were coming through the ether. The government had trucks which cruised around neighborhoods sniffing for the IF frequencies leaking out of TV sets and whacked you if you had an unregistered set.

I dunno much more about that, but I'm guessing the tax supported the BBC or something like that. Maybe that's still a common practice is some parts of the world?

Jeff

Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can smile when things are going wrong, you've thought of someone to blame it on."

Sasal Suzi wrote:

Reply to
Jeff Wisnia

No, there are long (relative) cables plugged into it.

Reply to
John Hines

I just didnt' think a system could be so badly designed that the signal path interferes with the power supply. in that case yes, there's an antenna in there, bu the fix is simple: get an amp that is not complete shit.

Reply to
j j

No, more likely the amp was feeding back signal through the line and a neighbor complained. In checking that out, he may well have found you amp was also going illegal. The cable companies hare sensitive to what you hook up to THEIR lines as it can cause problems for other customers.

I might add that if you are violating the contract you have with the cable company by feeding more TVs than you are paying for or are using pirate equipment to get stations you are not paying for it is YOU who are cheap and stealing from the cable company and all the users who are not stealing.

Reply to
Joseph Meehan

They also could have found the amp, especially if it's a cheapie, during a drive-by leakage test.

CATV companies are required to meet certain leakage standards. Some have a very hard time keeping their outside plant in passing condition, maybe they don't want you blowing the bogie for them.

Barry

Reply to
B a r r y B u r k e J r .

ya but those are shielded they pass signals in the hundreds of megaherz anyway, with or without an amp. if they weren't shielded they'd radiate either way.

Reply to
j j

When I worked for the FAA, I received pretty intensive training on tracking down sources of RF interference. You would be amazed at what odd stuff generates interference - even nonpowered things like a loose metal crossarm brace on a wooden telephone pole. The most common things though are items attached to TV's, especially amps. When we found the home or business where the interference was coming from, we were not allowed to take any action to correct the problem. Rather we had to contact a third party -like the cable company, power company, phone company, etc. Then they had to take action or face losing their licenses. This sounds like what happened in your case. As stated by other posters, the aircraft VHF frequencies are in the

115Mhz to 145Mhz range, just above the TV frequencies. But don't forget about harmonic frequencies - the offending item could be at a much lower frequency and the harmonic be in the aircraft band. And the offending item does not have to put out enough power to reach an aircraft. It only has to reach the ground antenna of the Air Traffic Controller.

Enuf

Reply to
Enuf

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