Make sure you tell that to your wireless vendors. :-)
----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP ----- Original Message ----- From: "Andreas Wiatowski" <andr...@silowireless.com> To: af@afmug.com Sent: Wednesday, March 2, 2016 8:43:45 AM Subject: Re: [AFMUG] Mikrotik SFP+ 10GB Faisal, Thanks for the great explanation. And I agree, that every sfp module seems to have a different “personality” in terms of strength. We have seen this in a number of occasions with MM fiber. I have been buying my SFP modules from a company in California called ROBOFIBER… the quality is good, and pricing is not bad. I do use some Maxxwave, Mikrotik and Finisar as well. In fact, I can’t believe how much we have started moving to fiber over the past year…..times have certainly changed! Cheers, ______________________________ Andreas Wiatowski | CEO Silo Wireless Inc. Email andr...@silowireless.com 19 Sage Court Brantford, Ontario N3R 7T4 (CANADA) Tel +1.519.449.5656 Extension-600|Fax +1.519.449.5536 |Toll Free +1.866.727.4138 From: Af [mailto:af-boun...@afmug.com] On Behalf Of Faisal Imtiaz Sent: Wednesday, March 2, 2016 1:47 AM To: af@afmug.com Subject: Re: [AFMUG] Mikrotik SFP+ 10GB Let me see if I can try to clear up some confusion and help in sorting this out. The optics, have TX and RX lasers... The TX will Transmit the Laser, and RX will Receive the Signal. You have the look at the MFG Specs to see what is the TX power and what is the RX sensitivity. Typically you need to have 5-7db of signal margin to have a link. Now, each fiber connector has a 'Loss', each fiber cable has a signal loss rating.... this is a figure you can ask the Dark fiber supplier to provide to you... Irrespective of whose fiber it is, when it was installed, or when a contractor worked on splicing it, they would have produced a 'loss' report.. e.g. 20 mile link is expected to have X db of Loss. So, on paper, one would do the calculations as follows = TX signal - Loss of all connectors and cable = RX Signal expected. This RX Signal needs to be 5-7db higher than the RX Sensitivity figure of that Optic module for a good solid link. Now, no two modules put out the same power, or have the same rx-sensitivity... there is always a certain amount of variation Now, no two modules rated for the same distance from two different mfg. have the same set of TX & RX Specs. So it is ideal to have a light meter (you can get one for as low as $50 from Ebay, Fiberstore etc, don't worry about having a cheap meter, having one is better than having none). This way one can measure the light coming out of the Optics and what is being received from the far side. One can use a relative test to measure loss across a cable (same optics, via a device that read RX & TX signals, such as the CCR) to determine that is the Loss on the cable end to end, based on this one can determine if there is a possible problem on a particular set of fiber cables.... and yes this can happen, for multitude of reasons, but before you jump on the issue being on the actual fiber cable, do test each jumper, clean each connector etc... cause most commonly such issues can come from bad jumpers or a connector that is not seated properly . :) Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net ----- Original Message ----- From: "Andreas Wiatowski" < andr...@silowireless.com > To: af@afmug.com Sent: Tuesday, March 1, 2016 9:53:54 PM Subject: [AFMUG] Mikrotik SFP+ 10GB <blockquote> Wondering if anyone has guidance on what is an acceptable receive power level that a CCR will report on an SFP. I currently have an SFP+ module that is reporting a -18. This is a 40KM module…I originally put in a 20KM module and it was reporting a -40. I was getting only a one way link. The path I estimate is about 20KM that I am linking…and I’m unsure of the quality of splicing…it is dark fibre I have from a municipality…been running 1Gbps on 20KM SFP’s until now. Thanks! Cheers, ______________________________ Andreas Wiatowski | CEO Silo Wireless Inc. Email andr...@silowireless.com 19 Sage Court Brantford, Ontario N3R 7T4 (CANADA) Tel +1.519.449.5656 Extension-600|Fax +1.519.449.5536 |Toll Free +1.866.727.4138 </blockquote>