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claiudio
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Copper link longer than 100 meters

Fri Apr 27, 2018 6:07 pm

I had to link two HDMI extenders with a CAT5e, because they didn't work through a wireless link (I don't know why).
I'm not sure how long the cable is, but using a badly off cable tester, a SC8108, it showed me ~ 190 meters over all 4 pairs.

After some trials (and many tribulations), the HDMI extenders started working when I used as "ethernet extender" a CRS326 and a RB2011. The RB960PGS I had available there, didn't even negotiate.
I tried one S-RJ01, and also it didn't never worked.

The RB2011 and the CRS326 negotiated 100 Mbps, on Gbps interface, so my question is: could be this link reliable?
It has to be running only for two or three hours, not longer, then it will be dismantled.

Anyone has some experience with beyond specifications copper link?
 
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Re: Copper link longer than 100 meters

Fri Apr 27, 2018 6:18 pm

My experience beyond specifications is to keep the Ethernet cable as short as possible, as isolated as possible :)
Maximum is really about 100 metres then collision detection mechanisms "break" the link.
Use some repeater in the middle and you should be fine.
 
mistry7
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Re: Copper link longer than 100 meters

Fri Apr 27, 2018 11:43 pm

 
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ingdaka
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Re: Copper link longer than 100 meters

Sat Apr 28, 2018 12:29 pm

In my practice up to 100m will work fine, longer than this you will have problems. I have reached max of 200m with cat6 SFTP cable and need to force connection to 10M on both sides! So in my opinion don't use cable in more than 100m.
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pe1chl
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Re: Copper link longer than 100 meters

Sat Apr 28, 2018 12:59 pm

That is right, with 10Mbit it usually works over longer distance than 100 or 1000 Mbit, but really when you have distances over 100m you should use fiber.
 
mistry7
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Re: Copper link longer than 100 meters

Sat Apr 28, 2018 1:06 pm

or 2 of S+RJ10 for 200m.....
 
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Re: Copper link longer than 100 meters

Sat Apr 28, 2018 2:44 pm

A pair of cheap pair of 3km single fiber transceivers and a fiber should do a better job at a lower price.
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Re: Copper link longer than 100 meters

Sat Apr 28, 2018 2:50 pm

A pair of cheap pair of 3km single fiber transceivers and a fiber should do a better job at a lower price.
when it is possible to exchange the CAt5 to Fiber yes, it is the best way....
 
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doneware
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Re: Copper link longer than 100 meters

Sat Apr 28, 2018 11:41 pm

the marvell phys in the crs3xx series support up to 175m as i recon
#TR0359
 
claiudio
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Re: Copper link longer than 100 meters

Mon Apr 30, 2018 11:35 am

First of all, thanks for all to gave time to write an opinion.
When I wrote, I gave partial informations: a good part of the link was CAT6 (maybe 40 %), but with lightning protection on both side.

But what I wanted was direct experience, not hint.
We didn't have time to put fiber optic, we cannot put repeater (this was an outdoor setup). The only other way -with what we had- was a wireless link, on which the HDMI extenders didn't work.

Well, now I can say that a temporary ethernet link shorter than 200 meters, between CRS3xx and RB2011, and if 100 Mbps are enough, is possible, but at own risk (as ingdaka's experience is really different).
And that it is a good idea to have in stock two S+RJ10.
the marvell phys in the crs3xx series support up to 175m as i recon
I read you only today, two days after. Good, ok. Did you hear or read it? I read specs, but I can't find it.
Maximum is really about 100 metres then collision detection mechanisms "break" the link.
Well, this is not a problem: on a full duplex link, CD is deactivated :-) .
For what I saw, it is rather a compromise between transmit power and sensitivity.
 
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doneware
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Re: Copper link longer than 100 meters

Tue May 01, 2018 12:32 am

the marvell phys in the crs3xx series support up to 175m as i recon
I read you only today, two days after. Good, ok. Did you hear or read it? I read specs, but I can't find it.
https://www.marvell.com/docs/phys-trans ... 014-07.pdf

it explicitly says cable length up to 170m are supported with cat5e.

i wrote a post about the crs326 some time ago. you can find it here: http://tikguy.wordpress.com
#TR0359
 
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Re: Copper link longer than 100 meters

Tue May 01, 2018 1:40 am

I had to link two HDMI extenders with a CAT5e, because they didn't work through a wireless link (I don't know why).
Most likely the HDMI extenders didn't work over the WiFi link because it's not Ethernet. Just because it's a RJ-45 connector, does not mean it's Ethernet. For the purpose, there is no reason to encapsulate the video in Ethernet frames.
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claiudio
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Re: Copper link longer than 100 meters

Tue May 01, 2018 12:58 pm

I had to link two HDMI extenders with a CAT5e, because they didn't work through a wireless link (I don't know why).
Most likely the HDMI extenders didn't work over the WiFi link because it's not Ethernet. Just because it's a RJ-45 connector, does not mean it's Ethernet. For the purpose, there is no reason to encapsulate the video in Ethernet frames.
Well, I would say you were right if the extenders didn't work even with two switch between.
But as they worked, and RB switches work with ethernet frames and not some exotic MAC protocol, my assumption, they were Ethernet, is probably true.
In the next few days I'll check if in the MAC table of the switch show up MAC addresses or not.
https://www.marvell.com/docs/phys-trans ... 014-07.pdf

it explicitly says cable length up to 170m are supported with cat5e.

i wrote a post about the crs326 some time ago. you can find it here: http://tikguy.wordpress.com
Thank you for both links.
About your posts on your site: few but well done :-)
 
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Re: Copper link longer than 100 meters

Tue May 01, 2018 8:40 pm

cable quality its very relevant in case of long distances

avoid cheap cables
avoid alloy cables, use only full copper cable

6a category cable using awg 23 or awg 22 wire diameter can help to avoid mitigation

shielded cable can help to ensure realiability

on long distance be sure you dont have ground potential differences between sites, because there is a great chance that current flow across your ethernet cable damaging equipment
 
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BartoszP
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Re: Copper link longer than 100 meters

Tue May 01, 2018 8:56 pm

Real admins use real keyboards.
 
pe1chl
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Re: Copper link longer than 100 meters

Tue May 01, 2018 9:14 pm

Note that this only works when there is absolute direct visibility! Like in: you can see a torchlight held up by someone at the other location.
Any walls or other obstacles will interrupt the signal.
 
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BartoszP
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Re: Copper link longer than 100 meters

Wed May 02, 2018 12:35 am

Maybe there is perfect visibilty? Maybe it's easy to install them with short cables? We do not know what the situation is and it could be (!!!) the answer for the problem.
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