RG-6 vs. RG-59 (1 Viewer)

[George Martin]

Hi
Just a quick question what is the differance between RG-6 and RG-59 and which would be better for a 25foot componant video run.
Thanks in advance.

 

[Glenn Overholt]

RG-6 is the better, by far. If it is available, go all out and get quad-shield too. It isn't that much more and the extra shielding might help out in a pinch.

Glenn

 

[George Martin]

thank you Glenn, when I posted the question I was at work and I thought I had a roll of RG 59 at home and a friend told me it was junk that I should be using RG 6 when I got home and looked it was RG 6 so I'm good to go.

 

[Bob McElfresh]

Ok, RG59 is not really 'junk'.

It has a bit less attenuation (signal reduction) over 100 feet, and the shielding does not work as well to keep Gigahertz level signals inside the center conductor. RG6 is designed better for this which is why it has become the standard for Sat systems and broadband CATV systems. (Mixing standard CATV, Digital, Cable Modem on 1 coax).

So you are going to make your own component video cable from this? What kind of signals are you sending: Component, Progressive or 1080 HD?

I'm a little concerned that it wont work well. It WILL work, but not like you might want.

My advice: build the cable first and test it before you go to the trouble of embedding it in walls. You might try this to test:

Get a copy of Avia (DVD setup disk) and using a real set of component video cables, examine the Fine Focus test pattern (The one with very fine black lines on a white background). Yes, move your DVD player near the display to get shorter cables to fit.

Then plug in your home-built cable and see if the appearance of the test pattern changes. Make sure your long cable does not coil up into a tight loop. Make it spread out in one big loop with gentle "S" bends.

Do any of the fine lines become blurry/loose focus with the long cable? If not, you are good to go.

My Concern: RG6 is more of a "Form Factor" rather than a statement of what signals it is designed to carry. Coax cables are designed with some frequencies and applications in mind. Your spool of RG6 CATV coax was likely designed to:

- Survive outdoor installations for 10-15 years
- Handle analog signals up to about 1 Mhz
- Handle digital signals up to 1-2 GigHz

Where is the part about analog video frequencies from 4-35 Mhz? To use a asphalt analogy, you may be trying to race stock-cars on suburban streets built with 25 mph speeds in mind. Sure, a race track, freeway, suburban streets are all roads and they all use the same asphalt: but they were each built with different speeds in mind.

So on the weekend, build and test the cable before doing the perminent install just to make sure it works.

And then let us know how it worked. Inquiring minds want to know.

 

[Ryan Patterson]

Ok, RG59 is not really 'junk'.

It has a bit less attenuation (signal reduction) over 100 feet, and the shielding does not work as well to keep Gigahertz level signals inside the center conductor. RG6 is designed better for this which is why it has become the standard for Sat systems and broadband CATV systems. (Mixing standard CATV, Digital, Cable Modem on 1 coax).

Thanks for the heads-up, Bob. I had my satellite system set up a few days ago and temporarily had a 50 foot line of RG59 cable between the grounding block and my receiver. I just upgraded that line to RG6 today, and was unimpressed to find no difference in quality between the two. After reading about the "benefits" that many satellite sites and message boards raved about, I was sure to see at least some amount of visual improvement, particularly a reduction in compression artifacts on some of the channels. However, you were right, whatever attenuation I supposedly lost going 50 feet with RG59 cable was superfluous. I have a Sony 43" progressive-scan TV, and I feel sorry for the poor folks with smaller interlaced CRT displays who get sold on this "gotta have RG6" garbage. Oh well, at least the cable was cheap ($20 CDN) and I'm still using the RG59 for my cable-tv line.

Regards,
Ryan

 

[Bob McElfresh]

Uhhh...

Between the Grounding Block and Receiver...???

You use RG6 between the Dish and the receiver. You can use any-old wire for a ground wire.

Look: the signals from your sat system are DIGITAL. This means they are less-sensitive to the cable than traditional analog. If you are using RG59 for a 50 foot run of satalite signals there IS more loss than if you had used RG6. But the digital nature of the signals makes it look like perfect transmission.

The Satalite signals are in the GigaHz range of frequency. RG59 was designed to handle into the MegaHz range so it does not do as well when you up the frequency into the GigaHz range. RG6 was designed to handle the higher frequencys.

I was sure to see at least some amount of visual improvement,

Not in this case. You got sucked into the idea that somehow a 'better' cable can improve the picture - it cant!

Let's all repeat Bob's Mantra:

A cable can in no way, shape, or form improve a signal. It can only damage it less than some other cable.

In this case, the PROPER cable to use for the frequencies involved is RG6. I dont think people on other sites 'raved' so much as 'insisted' the right type of cable be used.

I'm sorry you got the wrong impression. But I'm glad you are using the coax designed for the application.

Note: Be sure to tighten the "F" connectors with a wrench about a half-turn past finger-tight. The number one cause of poor quality and service calls is loose connectors.

 

[Ryan Patterson]

A cable can in no way, shape, or form improve a signal. It can only damage it less than some other cable.

So why didn't my RG59 setup look worse?

Thanks Bob,
Ryan

 

[JeremyFr]

Posted in the wrong thread.

 

[Bob McElfresh]

What benefit do I get if the digital signals look like a perfect transmission no matter what type of cable I use?

Not in every case will RG59 work as well as RG6. It's kind of like this graph:



The Red line is a RG6 cable. The Green line is RG59. (The blue is a mini-coax that I dont remember the RG number right now).

Look at the far right side - This represents the loss at 1 GigaHz. Which coax would you want for your system? The Red/RG6 of course.

Some people dont have as strong a signal as you have and the extra loss from the RG59 combined with a weak/poor Sat signal will cause freezes/pauses in their video. Even with a strong signal, there are storms, cloudy days, even high wind that affect the Sat signal strength.

If the RG59 you had worked fine all year long, you could have stuck with it. But it's not recommended by the Sat company, engineers, techs, or people on the internet. It comes down to the idea: use the right cable for the job. You are much less likely to have problems if you use the recommended cable.

 

[Ryan Patterson]

Hi Bob,

Considering I only vaguely know how dB works in the signal arena (the only dB I've really seen is when you turn up/down the volume on a reciever and you see the dB value on that change), I'm not sure exactly what the graph is supposed to tell me. The bird's-eye view of it seems to tell me that there isn't much difference between all 3 of those cable types. They all fall off at relatively the same rate, and when they reach 1Ghz they've all taken (what looks like) a significant drop.

The Satalite signals are in the GigaHz range of frequency... RG6 was designed to handle the higher frequencys.

But looking at that graph, even the RG6 cable has dropped 6dB by the time it has reached 1Ghz. How 'big' of a difference is 6dB (RG6) compared to 9dB (RG59) at that frequency? Since you say satellite signals are in the GHz range, what happens when it continues to climb to 1.5GHz, 2GHz, etc?

I combed Google Groups last night looking for somebody who hooked up RG59 cable and actually had a problem. I was only able to find one posting... a guy found that he couldn't get all his satellite channels until he switched over to RG-6. This would follow your theory assuming that the channels he couldn't get were in the high-end of the frequency range. It's interesting that I only found the one case... I guess everyone else was talked into using RG6?

On a side note, I've always questioned the significance of using "high-end" cables in other applications. I bought some Acoustic Research S-Video cable a few years back because I was seeing interference waves while using my came-in-the-box cables. While the extra shielding on the cable resolved this problem, I failed to see any improvement in picture quality vs. the cheaper in-box cables that would potentially "damage the signal more" than the higher-end cable. When I moved, I was able to go back and use my in-box cables because the interference from my old place no longer existed. (But I swtiched back to my AR cables since I wanted to use what I spent my money on ) I have a feeling that all you really gain when you spend the big bucks on cables is extra shielding, with everything else being moot unless you're looking at loooong distances. I even used a standard 10' composite cable to hook up my friend's DVD player via component connection to his 57" HDTV, and the picture was outstanding. Why spend $100+ on a Monster-type component cable when I get the same effect using an $8 cable that I bought at the Buck&Up store?

Another 2 cents,
Ryan

 

[JamesHl]

I had trouble getting some digital channels and I had some ugly pixelization when I used a RG 59 interconnect to hookup my digital cable. Also, my cable modem randomly dropped out. I had a terrible signal coming into the apartment, however.

 

[Bob McElfresh]

looking for somebody who hooked up RG59 cable and actually had a problem.

You did not find much BECAUSE everybody who knows about these things knows to use RG6. It's been fairly common practice since satalite systems started. All the installers use RG6. It's only an issue when someone wants to do it themselves and asks "Whats the difference?".