HDMI Cable Question

8

8bitbytes

SatelliteGuys Pro
Sep 8, 2003
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The primary ability to pass bandwidth is wire gauge. The thicker the wire, the more bandwidth it can handle. A "certified" cable is a cable design that has been tested by a certification authority and it was determined to successfully pass data sufficient to meet the requirements for that certification.

There are plenty of cables capable of passing an HDMI 1.3 signal that don't have the certified stamp on it. Do some homework and be careful to not fall for marketing scams. Blue Jeans Cable has some good reading on HDMI.
 
jayn_j

jayn_j

Press On Regardless
Supporting Founder
Sep 29, 2003
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Sheboygan, WI
The primary ability to pass bandwidth is wire gauge. The thicker the wire, the more bandwidth it can handle.

I would question this. Wire gauge controls cable resistance, which is not directly frequency dependent.

Bandwidth would be mostly controlled by cable capacitance which would shunt higher frequencies to ground.

I believe you will find that the 1.3 cables tend to have a larger jacket between the center conductor and the shield.

I agree with the rest of your comments, though.
 
8

8bitbytes

SatelliteGuys Pro
Sep 8, 2003
3,239
0
NoVA
I would question this. Wire gauge controls cable resistance, which is not directly frequency dependent.

Bandwidth would be mostly controlled by cable capacitance which would shunt higher frequencies to ground.

I believe you will find that the 1.3 cables tend to have a larger jacket between the center conductor and the shield.

I agree with the rest of your comments, though.

Interesting. Why do the heavier gauge wires conduct successfully where the lighter gauges do not? ie... 22awg HDMI 75 feet works fine for 1080p/60 but 26awg will not work at all.

What physical attribute of the heavier gauge allows it to work where the lighter gauge won't?

Thanks.
 
jayn_j

jayn_j

Press On Regardless
Supporting Founder
Sep 29, 2003
10,754
3,418
Sheboygan, WI
Interesting. Why do the heavier gauge wires conduct successfully where the lighter gauges do not? ie... 22awg HDMI 75 feet works fine for 1080p/60 but 26awg will not work at all.

What physical attribute of the heavier gauge allows it to work where the lighter gauge won't?

Thanks.

It is never simple. Smaller gauge wire will also usually have a thinner jacket. These two factors combined places the cables closer together, thus increasing their coupling capacitance. I believe you could get by with just a thicker jacket around the smaller wire, but you will probably find that the jacket costs about the same as the wire.

In the 1.3 cable, I would also guess that they don't twist the pair as much, thus cutting down on series inductance in the line.

It used to be that a twisted pair was a good thing at audio frequencies as it cut way down on crosstalk from adjacent pairs. However, it also acts like a low pass filter, and this is what likely needed the design change for 1.3.

Disclaimer: I don't design cables. I design sensor systems and airplane power systems.
 

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