MR52 over PoE+ and a strange cable phenomenon

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Head in the Cloud

MR52 over PoE+ and a strange cable phenomenon

Hello

 

I have a PoE+ connected MR52 that lives above a doorway and near a dimmer lightswitch. The light switch runs very hot. So hot, in fact, it has a heatsink installed on it. (I don't maintain that part of the premises but Ive mentioned maybe we want to rewire...)

 

The AP is a repeater only and does NOT receive or send data through the ethernet port. Only power. 

 

Pictures below.

 

I have this grey Belkin CAT5e cable which when used for PoE+ the device does great. It's link speed is about 120mbit/sec consistent. I change it to a new CAT6 cable in white (cable - https://tinyurl.com/y5ndpjdn) that looks better with the wall and is the right length and the speed suddenly plummets to 12mbit and gets erratic. 12-43-64-55-31. Jumps around a lot and nowhere near original. So I am thinking ok the white cable is bad. I try 4 other similar fitting cables I have onsite and similar issues. The grey Belkin is the only cable that delivers solid consistent performance. Do you think this is EMF coming off the electrical in the wall for the dimmer? All the lodge light electrical comes to meet at that point so maybe thats just what the deal is. Ive never run into this before. I ordered a shielded (STP not UTP) cable Cat6 cable in white 8foot to see if it remedies the issue. Just wondering what you guys think is happening. 

 

IMG_2214.jpgIMG_2215.jpg

 

 

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.
11 REPLIES 11
BrechtSchamp
Kind of a big deal

How are you powering the AP?

PoE+ from the injector you can see in the upper left of the pic. Tried w two different injectors same issue using both. Both work great w the gray belkin 5e cable.

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.

I wonder if it's switching between 802.3af and 802.3at for some reason. I assume the injector is rated for 802.3at?

yes its fully AT and reports as AT. Ive tried the OEM Cisco at injector and these great TrendNet ones that work awesome. Both exhibit the same behavior. Again, this one Belkin CAT5e cable totally rocks it while the other ones bite the dust. 

 

https://www.amazon.com/gp/product/B00BK4W8TQ/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

 

 

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.

If you have cable certification equipment I'd love to see the test results of the two cables. 

send me a link. i have a basic cable tester but i don't think that will work for certification testing. 

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.

>Do you think this is EMF coming off the electrical in the wall for the dimme

 

Yes.

 

I would get the dimmer replaced.  If it is hot it must be a very old school model that actually bled the energy off.  If it is likely to be an EMF issue caused by the dimmer then running the dimmer at 100% brightness should reduce the issue, and at low brightness the effect should be severe.

Will look into that. Do you think the STP cable will fix it in the meantime? 

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.

Silly thought, why not remove the injector. i.e. move the AP to where the injector is and mains power the unit directly?

Its not a bad idea but literally 2 feet in either direction yields a 20% loss in signal throughput to the gateway. I tried all over the wall and that is by far the money spot. The injector could go the other way but there's coffee and tea service right where the wires would go. Not pretty and will avoid it if i can. 

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.

mounting on that beam, is that a possibility?

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