You seem to have forgotten we are talking about analogue signals in a home environment where there are plenty of noise sources.

So got a nice thick Cat 6 RJ11 to RJ45 through the post today. Top sync - 77, can't beat the Billion 8800 R2 cable still at 79109.

Thick tells you nothing about the conductors, might just be an extra chunky layer of insulation or the centre plastic spacer making the difference

It's an interesting academic exercise but particularly interesting is that Billion supply the fastest syncing modem cables.

it could also that the action of plugging and unplugging cables is wiping the contact pins clean of any dirt / oxidisation so thereby improving speeds? i used to do this with double enders in jackfields when I worked for the bbc

Edited by threelegs (Wed 16-Aug-17 18:22:18)

Possible but you re-insert a poor cable and the speed goes back to where it was on first test. I used to make jackfields.

Regarding longer lead, I have experience with "Thin" Ethernet co-ax cables.

These either had to be extremely short, a few inches, or 8 feet (2.5 Metres) long minimum.

Anything in between gave problems.

Management complained about the general "excessive" length, so I experimented with varying lengths, to confirm or otherwise my general observations.

The equipment being connected was just too far apart for the "inches" leads.

It worked perfectly with the 8 foot and longer leads.

But generally was very poor with in-between lengths.

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With "Thick" Ethernet co-ax, it has markings at about 8 foot intervals.

Vampire taps had to positioned at that pitch between them, not necessarily on the marks themselves; but that minimum distance apart - otherwise problems.

Are you describing https://en.wikipedia.org/wiki/10BASE5 ?

That link shows the "Thick" Ethernet with Vampire Tap etc, so "Yes" wrt to the last part of my comment.

The first part, Thin Ethernet, used coax cable about 6 mm diameter, similar to domestic TV aerial coax; but slightly different impedance, 75 ohm if I remember correctly, rather than 72 ohn for TV.

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The Vampire Taps had to be carefully attached to the Thick Ethernet, including drilling in to it from its far side, often teetering at the top of a 25 foot, 3-section, ladder, with the bits and pieces tucked inside my shirt top.

On one occasion, the company insisted that a "networking" company deal with a new extension, 5 taps, at about 7 feet up.

I had to re-do 4 of them, they were so badly installed.

Just noticed that the Thick impedance is given as "50 ohm", so the same for the Thin Ethernet, as it was possible to connect them end to end , using a special but simple adaptor.

I did this on a few occasions for demonstrations to customers.