Re: [AFMUG] Weird cellular interference issue

[That One Guy /sarcasm]

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 <ch...@wbmfg.com> 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:* af@afmug.com
> *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" <geo...@cbcast.com>
> To: af@afmug.com
> 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 <dmmoff...@gmail.com> wrote:
>
>> This is above my pay grade.
>>
>> One of our customers was contacted by AT, and the customer put them in
>> touch with us.  AT was tracking down a source of interference.  The
>> interference was on a 10mhz wide channel centered on 828mhz.  At their
>> tower, AT 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 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.

Re: [AFMUG] Weird cellular interference issue

[Chuck McCown]

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: af@afmug.com 
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" <geo...@cbcast.com>
To: af@afmug.com
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 <dmmoff...@gmail.com> wrote:

  This is above my pay grade.

  One of our customers was contacted by AT, and the customer put them in 
touch with us.  AT was tracking down a source of interference.  The 
interference was on a 10mhz wide channel centered on 828mhz.  At their tower, 
AT 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 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.

Re: [AFMUG] Weird cellular interference issue

[Adam Moffett]

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" <geo...@cbcast.com>
To: af@afmug.com
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 <dmmoff...@gmail.com> 
wrote:

This is above my pay grade.

One of our customers was contacted by AT, and the customer put them 
in touch with us.  AT was tracking down a source of interference.  
The interference was on a 10mhz wide channel centered on 828mhz.  At 
their tower, AT 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 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.

Re: [AFMUG] Weird cellular interference issue

[Jaime Solorza]

that was my next suggestion

Jaime Solorza
Wireless Systems Architect
915-861-1390

On Mon, Jan 23, 2017 at 8:39 PM, George Skorup  wrote:

> 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  wrote:
>
>> This is above my pay grade.
>>
>> One of our customers was contacted by AT, and the customer put them in
>> touch with us.  AT was tracking down a source of interference.  The
>> interference was on a 10mhz wide channel centered on 828mhz.  At their
>> tower, AT 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 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.
>
>
>

Re: [AFMUG] Weird cellular interference issue

[George Skorup]

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 > wrote:


This is above my pay grade.

One of our customers was contacted by AT, and the customer put
them in touch with us.  AT was tracking down a source of
interference.  The interference was on a 10mhz wide channel
centered on 828mhz.  At their tower, AT 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 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.

Re: [AFMUG] Weird cellular interference issue

[Jaime Solorza]

cheap way to verify...use that aluminum tape or several windings of
foil...thicker the better at 800MHz..

Jaime Solorza
Wireless Systems Architect
915-861-1390

On Mon, Jan 23, 2017 at 8:32 PM, That One Guy /sarcasm <
thatoneguyst...@gmail.com> 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  wrote:
>
>> This is above my pay grade.
>>
>> One of our customers was contacted by AT, and the customer put them in
>> touch with us.  AT was tracking down a source of interference.  The
>> interference was on a 10mhz wide channel centered on 828mhz.  At their
>> tower, AT 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 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.
>

Re: [AFMUG] Weird cellular interference issue

[That One Guy /sarcasm]

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  wrote:

> This is above my pay grade.
>
> One of our customers was contacted by AT, and the customer put them in
> touch with us.  AT was tracking down a source of interference.  The
> interference was on a 10mhz wide channel centered on 828mhz.  At their
> tower, AT 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 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.

[AFMUG] Weird cellular interference issue

[Adam Moffett]

This is above my pay grade.

One of our customers was contacted by AT, and the customer put them in 
touch with us.  AT was tracking down a source of interference.  The 
interference was on a 10mhz wide channel centered on 828mhz.  At their 
tower, AT 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 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?