How did you “look at it” on the CAT5? > On Apr 24, 2019, at 1:28 PM, Bill Prince <[email protected]> wrote: > > Back when we were getting interference like this (around 12-13 years ago), > the noise was actually intermod from a couple of nearby high power > transmitters. We didn't see it until we were able to look at it with a high > frequency oscilloscope. > > It would come and go based on whether both of those transmitters were > operating at the same time. > > > bp > <part15sbs{at}gmail{dot}com> > >> On 4/24/2019 9:36 AM, Matt Hoppes wrote: >> If I take a volt meter and measure from ground wire/rack to earth ground. >> Would I see voltage if the transmitter is getting in at any significant >> amount? >> >>> On Apr 24, 2019, at 12:25 PM, Robert Andrews <[email protected]> wrote: >>> >>> & if the noise is coming from the grounding point? >>> >>>> On 04/24/2019 09:01 AM, [email protected] wrote: >>>> If you let shields float, they are a faraday shield. >>>> If you ground one end of the shields, they are faraday plus electrostatic >>>> shielding. >>>> If you ground both ends of the shields they do all of that but they also >>>> add magnetic shielding. >>>> However grounding both ends can cause a ground loop. >>>> -----Original Message----- From: Matt Hoppes >>>> Sent: Wednesday, April 24, 2019 9:22 AM >>>> To: AnimalFarm Microwave Users Group ; dave >>>> Subject: Re: [AFMUG] Fwd: CAT5. FM. And Rain >>>> Why do you mean "moved switching closer to the cluster", what is a >>>> "cluster"? >>>> Are you saying you floated the copper shields at the base of the tower >>>> and didn't ground them? >>>>> On 4/24/19 11:16 AM, dave wrote: >>>>> Matt, >>>>> I have that T-shirt For sure.. I was on a FM tower that was only 5kw >>>>> combined over one 5/8 coax for years. >>>>> Started with FSK then Cambium gear. >>>>> The things I noticed worse was the type of cable used. The longest time >>>>> we had used AL shielded type cable and eventually >>>>> relocated our switching near the base of the cluster which helped for a >>>>> while but after some time the AL shielding evaporated and >>>>> that type of cabling was barely good enough to get 10baseT out of it and >>>>> still had CRCs >>>>> We eventually moved to Superior Essex for everything on the tower and >>>>> used clips,hangers and grommets to get it off the tower leg. >>>>> Let the copper shields float on the cables and never looked back. >>>>> We have since moved completely off the tower last year but still didnt >>>>> have any issues at that time. >>>>> >>>>> What I did notice is that when we did move our switching and POE closer >>>>> to the cluster inside a nema enclosure it cleared a bunch of issues on >>>>> the cable for a long time. >>>>> >>>>> Dave >>>>> >>>>> >>>>>> On 4/20/19 10:06 AM, Matt Hoppes wrote: >>>>>> What's also interesting is none of the stuff in the shack has >>>>>> negotiating issues -- so it doesn't seem to be the switch as a whole >>>>>> getting swamped, but rather the CAT5 getting swamped going up the tower. >>>>>> >>>>>>> On 4/20/19 9:58 AM, Chuck McCown 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] >>>>>>>> <mailto:[email protected]>> >>>>>>>> *Date:* April 20, 2019 at 7:52:12 AM MDT >>>>>>>> *To:* Chuck McCown <[email protected] <mailto:[email protected]>> >>>>>>>> *Subject:* *Re: [AFMUG] CAT5. FM. And Rain* >>>>>>>> >>>>>>>> Yes. Problem goes away. >>>>>>>> >>>>>>>>> On Apr 20, 2019, at 09:51, Chuck McCown <[email protected] >>>>>>>>> <mailto:[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] >>>>>>>>>> <mailto:[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] >>>>>>>>>>>> <mailto:[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] >>>>>>>>>>>>> <mailto:[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] >>>>>>>>>>>>>> <mailto:[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] <mailto:[email protected]> >>>>>>>>>>>>>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>>>>>>>>>>>> -- >>>>>>>>>>>>> AF mailing list >>>>>>>>>>>>> [email protected] <mailto:[email protected]> >>>>>>>>>>>>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>>>>>>>>>>> -- >>>>>>>>>>>> AF mailing list >>>>>>>>>>>> [email protected] <mailto:[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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