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In Coax Video Cable - what is RG & AWG?


Guest duckling
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Guest duckling

I was looking at Belden 1694 and 7731A.

 

Belden 1694 = RG 6/U and AWG 18 (Recommended by Robert)

 

Belden 7731A = RG 11/U and AWG 14 (Saw Richard using)

 

which one will be better in performance for SCV cables?

 

Any feedback and comments are welcome.

 

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I assume u are cabling SCV within a HDB premise. The length can't be more than 50m rite?

 

Then RG-6 is more than enough. RG-11 is v. good, but its overkill. Furthermore, RG-11 is not easy to handle.

 

RG-11 used in many US HT since their C-band BUD (Big Ugly Dish) for satellite TV is situated far from their HT. Since so long distance, need thicker cables to minimise loss.

 

How long are u going to run the cables?

 

But if just for SCV, use RG-6 is more than enough. SCV themselves use the thinner RG-59, which is 22AWG (or 20 AWG).

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Guest duckling

My maximium lenght is abt $10m, I guess Belden 1694 is better than normal SCV cable and good enough for it.

 

Thx guys.

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Guest jonlee

but is there really a need to use good quality 1694 for watching scv programs when there are metres and metres of shabby cabling before the scv box?

 

 

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1694 is a practical cable for any co-ax application.

 

But to use Moter cables for SCV, then no point.

 

 

"You can be poor, but there's no reason to make yourself any poorer."

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I think Belden 1695A or 7731A will be better choices but may be a bit more expensive.

 

I am using 1695A as my digital audio coxial cable n the 7731A as my SCV antenna cable.

 

If budget is a concern, Belden 9116 is a good choice.

 

Check the spec, the 1695A has higher attenuation than the 1694A across all frequencies. i.e the 1695A will have a greater loss/metre than the 1694a. The reason why 1695A is very much more expensive is it's plenum version (thanks JAG for the explaination) somethin to do with more safety and easier installation.

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I think 1695A is $9/m & 1694A is $4/m.

 

The diff. is in their Plenum rating or low smoke emission properties. Its not cheap to obtain Plenum rating and to manufacture low smoke dielectric & insulation.

 

IMHO, if u feel there is a danger of a fire starting near your expensive equipment, then get the Plenum version. Its mandatory for commercial buildings to install Plenum versions to comply with fire safety regulations since very long runs are used. Therefore, spec. tolerance is compromised.

 

Otherwise, the 1694A has tighter tolerances and lower loss.

 

Check bleden's webby for the technical specs for 1694 & 1695.

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I think 1695A is $9/m & 1694A is $4/m.

 

The diff. is in their Plenum rating or low smoke emission properties. Its not cheap to obtain Plenum rating and to manufacture low smoke dielectric & insulation.

 

IMHO, if u feel there is a danger of a fire starting near your expensive equipment, then get the Plenum version. Its mandatory for commercial buildings to install Plenum versions to comply with fire safety regulations since very long runs are used. Therefore, spec. tolerance is compromised.

 

Otherwise, the 1694A has tighter tolerances and lower loss.

 

Check bleden's webby for the technical specs for 1694 & 1695.

 

 

Didn't see the specs before buying, but was told by the salesman that 1695A is an "improved" version of 1694A therefore didn't doubt the quality of it. But thanks for pointing out the difference is specs.

 

Come to think of it, seems like the salesman has "ripped" me off by asking me to buy the 1695A instead of the 1694A.

 

I am using the 1695A as a digital coxial cable n sounds quite ok to me.

 

Hmmmm how come the 1694A has tighter tolerances and lower loss than the 1695A. Thought that both should be the same but only with Plenum rating ???

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Cos the material for the dielectric insulation and outer jacket used is slightly different.

 

Although they are designed to be the same, the compromise is in these materials. These materials affect the electromagnetic fields associated with time-varying currents. Just the dielectric alone, the capacitive nature between 2 materials are different. This determines the loss, impedance etc.

 

The 1694 uses materials that best able to allow optimum signal transfer as intended with minimum side-effects.

 

1695 uses an alternate low smoke material to replace an otherwise optimal dielectric and jacket. Thus, this introduces unwanted "side-effects".

 

Of course belden can adjust the geometery of the cable, but that will lose the RG-6 specifications.

 

RG-6 specs clearly states many specifications that are fixed, like geometery, size/diameter of conductor/dielectric, impedance, capacitance, inductance, relative episilon, EMC.......

 

I can go on and on with more explanations, but I better don't, lest u want to fall asleep.

 

How I know? I'm a radio electronics engineer.

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