this guy was running something in 800mhz the poe was interfering with, he traced it to the poe, if i recall correctly he said it was emitting even with the radio cable unplugged
On Mon, Jan 23, 2017 at 10:16 PM, Chuck McCown <[email protected]> wrote: > They don’t have a cellular extender do they? > Can you take an offending WiMax to a location with a spectrum analyzer to > see if it really may be radiating on that freq. > > Also, if there is a strong transmitter nearby, you can have > intermodulation products being passively created in the WiMax. Like TV, FM > broadcast etc. > > Does the WiMax have an external antenna that can be disconnected to see if > the problem goes away? > > Wrap the WiMax with foil and see if the problem goes away. > > If it is no interference generated with the same gear at one location but > interference at another location, intermod seems likely. > You can put ferrite on the CAT5, use shielded CAT5 and put loops in it to > decouple the radio from anything in the house. > Or just power the CPE with a battery up on the rooftop to see if it still > noisy. If so, then stop looking at sources in the house. > > Again, intermod, bad radio would be my two top picks. > > *From:* Adam Moffett > *Sent:* Monday, January 23, 2017 8:49 PM > *To:* [email protected] > *Subject:* Re: [AFMUG] Weird cellular interference issue > > Not shielded cable, but still a good idea. > > This person doesn't have HAM equipment, but I'm thinking something along > the same lines. Maybe a device in the house is inserting this signal on > the neutral or ground wire of the A/C. Maybe A/C ground is bonded to D/C > ground in the PoE. Maybe D/C ground is bonded to a ground plane in the > panel antenna. Lots of maybes there. Maybe I'm talking out of my hole. > > > > ------ Original Message ------ > From: "George Skorup" <[email protected]> > To: [email protected] > Sent: 1/23/2017 10:39:18 PM > Subject: Re: [AFMUG] Weird cellular interference issue > > > Is it shielded cable? Sounds like the shield has become a radiator, aka > antenna. Detune it by adding or removing some cable length? > > On 1/23/2017 9:32 PM, That One Guy /sarcasm wrote: > > place the poe in a faraday cage, it will resolve it, we have a HAM guy > that has something in 800mhz, same issue, suggested he do that, it resolved > it, he didnt describe what cage he built > > On Mon, Jan 23, 2017 at 9:24 PM, Adam Moffett <[email protected]> wrote: > >> This is above my pay grade. >> >> One of our customers was contacted by AT&T, and the customer put them in >> touch with us. AT&T was tracking down a source of interference. The >> interference was on a 10mhz wide channel centered on 828mhz. At their >> tower, AT&T is seeing it 15-20db above the noise floor, so it's pretty >> significant. >> >> Using their spectrum analyzer they tracked it down to our customer's >> house. The customer has a wimax CPE on their roof. Unplugging the CPE >> makes the interference go away, plugging it back in brings the interference >> back. Every time. AT&T guy goes to another customer's house and >> confirms that other CPE at different locations don't produce this >> interference. >> >> We figure it's a malfunction in the CPE, so we replace it. Interference >> still present. >> We replaced the PoE. Interference still present. >> >> So we know the Wimax unit doesn't originate the 828mhz signal, but it's >> somehow an accidental component of a system that does. >> >> WTF could be going on? >> >> > > > -- > If you only see yourself as part of the team but you don't see your team > as part of yourself you have already failed as part of the team. > > > -- If you only see yourself as part of the team but you don't see your team as part of yourself you have already failed as part of the team.
