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In Reply to: does coax cable quality matter? posted by fohara@san.rr.com on March 24, 2005 at 15:44:33:
yes, it matters if you believe in it.
Follow Ups:
We're not talking about mega-buck designer audio cables where only golden ears imagine they hear a difference.At high video and RF frequencies the quality of the cable does matter especially with long cable runs. There are specs that will give you an indication of how well the cable will perform. dB loss per 100-feet at a given frequency is just one indicator. How well the cable holds up to UV from sun light or how the jacket holds up over temperature extremes are also important for outdoor use.
Just as an example, typical cheap RG59U coax might have a signal loss of more than 3db per 100-feet at 150-MHz. What does this mean? You just lost half your signal through the cheap cable. If your antenna has a gain of 6db you just threw 3db away in cable loss. There are better cables with lower loss characteristics - like RG11U which is about 1.5db loss per 100-feet at 150-MHz.
For RF and video the quality of the coax cable matters - a lot.
I think there's somthing wrong with what you belive about the propagation of electromagnetic information through a coax cable.You say > > "...100-feet at 150-MHz. What does this mean? You just lost half your signal through the cheap cable." < <
But in my house, I have over 200 feet of cheap cable between the satellite dish and the plasma at the other end of the house, with a dozen or so splices and junctions and receivers and boxes and such like in the betwixt. By your belief system: I should have lost both halves of my signal!
Problem is: I believe what I see, and I see: the picture is fine!
I think people are inclined to believe things in spite of the facts--which is why marketing is such a successful and profitable religion.
I used to have the same problem about milk.
I started drinking 2% milk a while back, thinking that I was consuming 98% less milk fat. But after two decades, I'm as fat as I ever way--fatter even.
Then one day I discovered that "whole" milk...is only about 4% milk fat.
So really, there is hardly any difference between whole milk and losing half your signal with the 2% milk.
I gotta beleive: same is true with wire.
Anyway, I can't tell the diffence, but hey, if you think the stars and motions of the planets hold an influence over your enjoyment of video--God bless!
Cable specs get a bit trickier with RF. Basically, if you don't have a problem now, I wouldn't worry about your cable. That being said there can be huge differences in RG cable for antenna usage. The better the cable, the better the noise rejection and signal loss characteristics.The best I've found for general antenna use is the quad shielded stuff from Radio Shack. I use it for all my RF patch cables and such. It's stiff and a bear to work with, but has very low signal loss at TV through broadband data frequencies, and excellent noise rejection (with the quad shield and all)
And you're right... it's a royal pain to work with. Those crimp on connectors take some practice get them on correctly even with the proper tools. I'm using RadioShack quad-shield RG6U for my FM antenna.
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