Extending Ethernet through wall without too many boxes - Xpost

May 13, 2024 Last reply: 2 years ago 27 Replies

You can test this.

One of the Marvell NIC chips, has an impedance tester (page 13):

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(their own flavour of TDR). And it can tell you "shorted", "open", or "characteristic impedance". Since there are four pairs and the Marvell is GbE, there are four words on the screen, one word for each pair. When I first got the P5E Deluxe, the RJ45 was dirty, and had one open contact, so I got to use the VCT test right away. And one of the pairs was rated "Open". Re-inserting the RJ45, five times, was sufficient to clean the contact.

Eth.Cable P5E Deluxe -------------------- Router with power off ("no heartbeat") booted and running Now, you are testing cable, and router RJ45 contacts. onboard Marvell chip.

Marvell still lists some parts that have VCT capability, but I don't know how easy it is to find a working specimen at retail.

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The error rate on Ethernet, is finite. It's not zero. And our objective as hobbyists, is to not make it worse :-) I occasionally run SHA hashes on network transferred files, to keep an eye on the enhanced error rate. I've never seen a bit flipped in a transferred file... yet. But the opportunity for that, does exist.

Paul

That's interesting, I hadn't come across those. They look quite handy.

For the record those are PHYs - they go after the MAC chip which is the one that talks USB/PCI/PCIe/... There might be a USB ethernet adapter which has such a Marvell PHY after its MAC, but it's a job to find one unless you look at teardown photos. Many cheaper devices have combined MAC and PHY in the same silicon so that makes them less likely. You could hunt around for PCI(e) cards with Marvell PHY chips on them I suppose.

But it might be easier just to buy a proper TDR, ~$80:

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You're several levels of checksumming at that point, which covers a multitude of sins. But bodging it now stores up problems for the future - our entire office building had to be rewired because the contractors who installed cat5 when it was built only wired 2 pairs, which was all that was needed for 'super fast' 100Mbit at the time (the cable was fine, but all the terminations had to be redone).

2.5/5/10G copper is becoming more common and better to do it right than do it twice.

Theo

All this theory and possibility is trumped by the fact that a soldered joint actually leaves the pairs a lot more twisted than an RJ45 plug and socket does.

And a soldered joint inside a house is far less likely to corrode than a punch down...

I repeat my mantra. Punch down is designed so that numpties can do wiring, and the Ethernet specification is robust enough for rather crap connections not to fail.

And punchdown is rather crap compared with soldering.

In many years of Ethernet I have NEVER come across a link that 'worked with high error rate'

They work, or they don't IME.

PS you won't see errors in file transfer using TCP/IP because that has its own error checking. The effect of corruption on IP links is to reduce throughput, as the retransmissions become more frequent.

If your Ethernet is doing full speed IP transfers it has nothing wrong with it.

How far is your deck?

I get good coverage all over the garden from the router _inside_ my home office - a timber framed, plasterboard lined room. Out to at least 30m.

OTOH we don't have many neighbours to interfere with the signal.

Andy

Are you aware that some WAPs can be configured as repeaters. No need for any additional UTP cabling

Yes, thanks.

The issue is getting enough signal to the WAP.

We sit right outside the bifold doors which is where the WAP would have to go.

Problem may have been solved by a new WiFi6 WAP in the living area, which is far more effective than the old route which was being used as a WAP.

Cheers

Dave R

Deck is directly outside the bifold doors of the rear living/dining/ cooking area.

The problem seems to be the bifold doors blocking the WIFi signal.

However have just installed a new WiFi6 WAP w2here the old WAP was, and the signal is much stronger.

So I may not need the wiring after all.

Cheers

Dave R

If you still have problems, you could try using a directional (gain) antenna, a booster amplifier or a combination of both, such as

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If you need to buy cables with SMA connectors, be aware that they come in two flavours, SMA and SMA-RP (Reverse Polarity). Wifi antenna connectors are usually SMA-RP.

At 2.4GHz the cables are lossy, and it is very easy to loose more signal in the cable that you are likely to gain with a gain antenna or a signal amplifier.

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