I presume it was OK when first commissioned and later developed the problem?
From: Ken Hohhof Sent: Saturday, April 20, 2019 9:08 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Fwd: CAT5. FM. And Rain The problem could be complicated, I think people are suggesting mechanisms like when the tower is wet various corroded metal-metal connections turn some of the FM transmitter power into harmonics which interfere with your Ethernet. Vaguely similar to the reason some tower leasing companies insist on low-PIM coax connectors and jumpers, PIM being passive intermodulation. Although PIM occurs when you have 2 or more high power signals on different frequencies, and the corroded connections create sum and difference frequencies. What I’m saying is the fix might not be as simple as grounding something. More like a generic FM transmitter interfering with Ethernet problem that gets worse when stuff is wet. There is an outside chance some of your Ethernet connections are getting moisture in them, especially if you have multiple RJ45 connections at things like surge protectors. It wouldn’t hurt to check all those connections for water and corrosion, dry them out, replace any suspect connectors, and put a dab of silicone grease in them. But given that the problem goes away when you turn off the RF, that’s probably not it. I only mention it because I have seen Ethernet problems at towers in protracted rainy weather even with no FM transmitter. BTW, am I reading your post correctly that you have this problem on all the radios, not just one? Not sure how difficult this would be, but one approach would be to move the Netonix to a weatherproof box at 250 feet, and run fiber + DC power to it. Maybe include a DC surge protector on the power, plus unlike Ethernet, you can filter the heck out of the DC power, it won’t care. From: AF <[email protected]> On Behalf Of Matt Hoppes Sent: Saturday, April 20, 2019 9:43 AM To: AnimalFarm Microwave Users Group <[email protected]> Subject: Re: [AFMUG] Fwd: CAT5. FM. And Rain Not in liquidtight. Have ground lifted and grounded. No change. Have not wet things (would be difficult - no ready source of water) Obviously RF is getting into the Ethernet, when things are wet. I’m just trying to figure out why. Clearly a connection is being made somewhere it shouldn’t be. On Apr 20, 2019, at 09:58, Chuck McCown <[email protected]> wrote: So moisture + rf = Ethernet interference. Just as originally stated. No standing waves. Is your cat5 in liquidtight? Have you played with grounding & ungrounding the shields? How about taking a garden sprayer and selectively wetting things? Sent from my iPhone Begin forwarded message: From: Matt Hoppes <[email protected]> Date: April 20, 2019 at 7:52:12 AM MDT To: Chuck McCown <[email protected]> Subject: Re: [AFMUG] CAT5. FM. And Rain Yes. Problem goes away. On Apr 20, 2019, at 09:51, Chuck McCown <[email protected]> wrote: Have you killed the ref when you are having the problem? Might not be ref related. Sent from my iPhone On Apr 19, 2019, at 7:11 PM, Matt Hoppes <[email protected]> wrote: 19watts On 4/19/19 8:58 PM, Chuck McCown wrote: What is the reflected power when you are having problems? Sent from my iPhone On Apr 19, 2019, at 6:41 PM, Matt Hoppes <[email protected]> wrote: My thoughts too. But the reflected power right now is only 19watts out of 9,000. On Apr 19, 2019, at 20:14, Chuck McCown <[email protected]> wrote: My guess is that the FM station has a problem with the antenna or transmission line. Moisture throws off impedance somewhere and you have a strong standing wave on the transmission line. Probably a bad connector. Sent from my iPhone On Apr 19, 2019, at 5:52 PM, Matt Hoppes <[email protected]> wrote: Looking to the wisdom of the AF group on this. I have some equipment on an FM tower. It’s a 9kw station around 150ft. We are at 250ft with two sectors and a backhaul. Netonix switch in shelter. Nothing else on the tower. Normally all is fine. When it rains or is very moist out (heavy heavy fog) we start having major Ethernet negotiation issues. The ports will go from 1Gig to 10F sometimes. Sometimes drop completely. I’ve got ferrite beads wrapped about 5 times top and bottom. Any further words of wisdom on what to try? I suspect some odd grounding issue. But not sure how to track it down or isolate it. -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com -------------------------------------------------------------------------------- -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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