RG6 for HD

[cmtar]

Why do I need RG6 for HD, i have always used RG59 for SD.

[HDTVsportsfan]

In short, RG6 can handle the frequency and voltages needed better. Others can give a much better explanation. For short runs, you could probably get by w/ RG59. YMMV, lots of variables come into play though when using RG59.

[phat78boy]

As HDTVsportsfan said, you can use RG59, but it is much less forgiving. You will need to have short runs and near perfect ends. RG59 looses too much signal and that is why RG6 is recommended.

That said, if the lines are already in place, you might as well try them before replacing them with RG6.

[P Smith]

Why do I need RG6 for HD, i have always used RG59 for SD.

Old DTV dishes (LNBF,switches) used IF range 950...1450 MHz; newest (AT9/AU9) dishes - from 250 MHz to 2150 MHz.
Feel the difference ?

[carl6]

One of the most important differences is the ability of the coax to carry DC power from the receiver to the dish. The new 5-LNB dish used for HD uses a lot more power than the old round dishes did, or even the 3-LNB dish.

RG6 has a much larger center conductor, and the actual spec is for RG6 with a solid copper center conductor (as opposed to copper clad steel).

Carl

[P Smith]

DC is less important then high attenuation of 1650-2150 MHz range of RG-59.

[carl6]

Both are important considerations, and collectively contribute to the argument for using RG6.

I don't know which would become the "critical path" first.

Carl

[glennb]

It's always been RG6 since DIRECTV started up.

[Nick]

Why do I need RG6 for HD, i have always used RG59 for SD.One word: Bandwidth.

Friends don't let friends use RG-59.

[BattleZone]

Most RG59 is only rated to carry signals up to 1 GHz. Good-quality RG59 will often work for SD DirecTV sat runs if the runs are short, because the signals top out at 1.45 GHz. Though higher than the cable rating, it can pass these signals without too much loss for a short distance. As the cable length increases, the higher frequencies suffer too much line loss, and you start losing the upper transponders.

As you try to send higher and higher frequencies through the cable, line loss increases. HD DirecTV signals use up to 2.25 GHz, which is far too high for RG59 for any length.

Then there is the DC voltage line loss. DC current has lots of line loss, and needs thicker, higher-quality (read: solid copper) conductors to reduce the loss as much as possible, especially with runs up to 150 feet. RG59 uses much thinner conductors, and therefore has much greater line loss per foot. Once the 19V signal sent out by the receiver drops below 17V, the multiswitch will no longer switch, and you'll lose all of your even-numbered transponders.

Thus the requirement for RG6 (DirecTV specifically requires solid-copper center conductor RG6 dual-shield with 60% shield braid, rated to 3 GHz, as their minimum standard).

[P Smith]

"HD DirecTV signals use up to 2.25 GHz" - quite high, in reality up to 2150 MHz +/-20 MHz.

[cmtar]

so......are you saying i cant use RG59? :)

[HDTVsportsfan]

If at all possible you should replace the RG59. It will just take out a weak link/variable if you have problems. But that may be easier said than done.

[Nick]

so......are you saying i cant use RG59? :)So, are you saying you want to use RG-59?

Go ahead and use it -- it's your call. :rolleyes:

[brambo]

I have a related question. The installation video at solidsignal.com says that RG-6 with a solid copper center conductor must be used. Copper coated steel is not acceptable. Most RG-6 that I have found is copper coated steel. Does anyone know if this is really a problem?

[carl6]

I have a related question. The installation video at solidsignal.com says that RG-6 with a solid copper center conductor must be used. Copper coated steel is not acceptable. Most RG-6 that I have found is copper coated steel. Does anyone know if this is really a problem?

Solid copper conducts DC voltage better, which is why it is specified. It has no effect on the rf frequencies that are used (copper clad steel works fine for the rf).

If your coax runs are going to be under about 100 feet, and you won't be using a non-powered multiswitch, then either is acceptable. If your coax runs are going to be longer and/or you will be using a non-powered multiswitch (WB68), then the solid copper is preferred.

Carl

[brambo]

Thanks for the info. My runs will be about 25 ft from a WB68. I think I will run a test with some old copper coated steel coax just to test the signal levels before I do the final routing. If the levels are low then I'll buy the better stuff.

[John-MAVA]

Why do I need RG6 for HD, i have always used RG59 for SD.

RG59 is supposedly unable to carry the high bandwidth associated with HD programming and you must always run new wires if you find any*