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Interference with repeaters?

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Tue, 06/14/2022 - 21:48

#1

KE0RSX

KE0RSX's picture

Interference with repeaters?

Hi, everyone,

If this is the wrong place please let me know (or move the post). I'm curious if anyone has experienced interference between their 5.8GHz nodes and 2m repeaters? Our setup is three Rocket M5's with 120-degree sector antennas mounted about four feet below our 2m and 70cm antennas for the repeaters. We've been noticing what we thought was a squelch tail on the 2m repeater and someone suggested it might be the nodes.

Has anyone experienced this at all? And if you did, what did you end up doing to solve the issues?

Thanks and have a great night. :)
Patrick.

Wed, 06/15/2022 - 00:02

#2

K6CCC

K6CCC's picture

I would not expect it to be a

I would not expect it to be a problem, but anything is possible. What actually is happening?

Wed, 06/15/2022 - 08:55

#3

nc8q

We've been noticing what we thought was a squelch tail

"We've been noticing what we thought was a squelch tail"
Hi, Patrick:

I have never heard of this.

If practical, please be more specific.
IMHO, 'squelch tail' is
the time elapsed from a carrier going away on an FM receiver and the loss of (squelching) of audio
and/or
the noise heard on the receiver audio during this time.

I cannot, off hand, conceive of a way for a Rocket M5 to interfere with a 144-148 MHz receiver.

73, Chuck

Wed, 06/15/2022 - 10:18

#4

kc8ufv

kc8ufv's picture

I'm not certain how a node

I'm not certain how a node would cause that, other than possibly raising the noise floor. To a continuous receiver such as FM or AM, AREDN nodes will be extremely short bursts of signal, with the frequency increasing with utilization, though at idle, a packet every 5-10 seconds or so. The description sounds like either the squelch circuit is improperly adjusted or otherwise malfunctioning, and the repeater is thus relying on the (much slower) PL decoder.

Wed, 06/15/2022 - 16:39

#5

KE0RSX

KE0RSX's picture

So, here's the deal...

We've noticed about a one to two second burst of static after someone unkeys on the repeater. Originally, we thought it was a squelch tail setting, but changing that from 1,000ms to 250ms didn't affect it. So, we assumed it was someone using a crossband repeater on the input frequency. On another site, we have our nodes (three TP-Link CPE210s, three TP-Link CPE510s and a PTZ camera mounted on the same pole as the Railroad monitoring group has their 2m and 900 MHz antennas for their live feed. On the live feed, you can hear a burst of static at a regular interval (here's a link to the live feed https://www.youtube.com/watch?v=eVykaCzNB8c ). They're saying it's our nodes causing the static. There's also wind noise, but the static is clearly there.

I'm trying to isolate whether it could be the nodes, the PTZ cameras (cheap Chinese knockoffs), or something else.

Have a great day. :)
Patrick.

Wed, 06/15/2022 - 18:42

#6

kc8ufv

kc8ufv's picture

Those static bursts are not

Those static bursts are not consistent with the signals a wifi radio would generate. You're looking for a nearby transmitter malfunctioning that transmits in the same band, or a downward harmonic of the band.

Wed, 06/15/2022 - 20:39

(Reply to #6) #7

KE0RSX

KE0RSX's picture

From my understanding, it

From my understanding, it started when we hooked up our nodes and our PTZ camera. I'm wondering if it's something in the camera itself. I haven't been on that roof since we put up the nodes, but I will be this weekend. So, I'll make sure there isn't anything else up there.

Have a great evening. :)
Patrick.

Wed, 06/15/2022 - 21:56

(Reply to #7) #8

N7TZK

What about the CAT5e cable?

I have on occasion run into cases where Ethernet cable caused RFI to a 2m frequency. Switching to shielded Ethernet cable took care of the problem in my case. And at a 100 mile race event recently, the 2m frequency I was monitoring was getting hammered by a nearby Ubiquity node plus attached VoIP phone. Problem appeared to be the wall wart associated with the phone. I have also heard of Ubquity power injectors occasionally causing issues, though in the specific cases I'm aware of, it was UHF interference. In any event, remember the node itself isn't the only device involved when using a node. Your mileage may vary...

Dave

Tue, 06/28/2022 - 15:26

(Reply to #8) #9

ng1p

I do see interference on 2

I do see interference on 2 meters coming from my 2.4Ghz Rocket. Its comes and goes. It does seem to float from 144.8 - 145.8Mhz. I run a simplex packet node and about once a month it will fall on 145.07 with about a S5 noise level. Powering it down and back on seems to fix it for about one month. I will try and replace it at some point to see if that helps.

73 Bill NG1P

Thu, 06/16/2022 - 07:39

#10

nc8q

Has anyone experienced this at all?

Hi, Patrick:

I would want to hear the repeater's receiver audio and watch the receiver's S-meter and
be able to turn the AREDN gear off and on.

73, Chuck
'

Thu, 06/16/2022 - 08:27

(Reply to #10) #11

KE0RSX

KE0RSX's picture

I'm planning on going out

I'm planning on going out today, if I can get access. It's on the college campus and there's a new lock on the fence. So, I need to get the combination for it. Once I get in, I plan on shutting everything off and trying the repeater (I'll be in front of it at that time). The antenna for the repeater is about four feet above the nodes and camera.

In reply to Dave's comment about shielded cables, we were considering that as well. The theory being with all of the equipment in the building, there might be some crosstalk and other interference. Although, some of their equipment is being fed by the blue UTP cables that you buy at Menards (think Lowes or Home Depot). At least it looks like the same cable. I haven't actually grabbed any to find out for sure.

My plan is to unplug the camera and unhook everything from the switches. Then reboot all of the nodes and see if it changes anything. If they boot up and stay up, I'm going to upgrade them all to the latest stable version. Then, I'll start connecting things to see if they break. If everything works, I'll leave the camera unplugged and call that the culprit. If not, we'll keep looking. At the same time, I'll test the repeater out to see if the "squelch tail" is there. If I can, I will record it.

I *might* be able to get some short videos of what's happening. The problem is, I'll have to upload them to my Facebook account and share that (or maybe share it to the AREDN group there). I could link to them here, if necessary.

This is all vaguely related to the issue that I posted in the nodes forum (about the nodes rebooting), as it might be a related cause. Especially if the camera is the problem.

Have a great day. :)
Patrick.

Thu, 06/16/2022 - 11:44

(Reply to #11) #12

nc8q

I plan on shutting everything off and trying the repeater

Hi, Patrick:

I recommend, first, trying the repeater with your normal AREDN equipment running, then
turning items off and checking the repeater for a difference.
Take some extra POE injectors and ethernet switches to swap.

73, Chuck

Thu, 06/16/2022 - 15:23

#13

KF7BWS

KF7BWS's picture

Interference with repeaters?

Patrick
I can not say that the ARDEN Nodes are absolutely not causing the problem but extremely unlikely.

The problem relies more on the repeater side. there are far more possible causes for this problem than could be discussed here. The first thing that came to mine is the potential for a problem caused by intermod. the mixing of two or more signals. Many things can cause intermod. A loose nut or bolt corrosion of metal connection. it could be as simple, and hard to find as a screw in the gutter or even faulty equipment or leaky coax shielding or ungrounded equipment cabinets, then there is the possibility of outside source intentionally interfering, unlikely.

Start by examining whether or not it is constant or intermittent. does it happen only when a certain ham is transmitting or if it happens only to one or more people who are monitoring. Does it happen with all gear, hi end gear or low end gear is using the repeater. Isolate whether the squelch is in the receiving end of the repeater or the transmitting end or if it is produced in the repeater controller.

I believe you will find that it is not the ARDEN nodes. if you shut down the nodes and test the repaeter agin, you will find that the problem is still there.

Thu, 06/16/2022 - 15:37

#14

KF7BWS

KF7BWS's picture

Interference with repeaters?

Another thought came to mind. if you have several ARDEN nodes they are connected to an Ethernet switch. Many switches are very noisy one of the worst is Cisco. Shut only the switch off and test the repeater. If the problem goes away relocate the switch away from the repeater equipment and / or ground the Switch casing. Try shielded Ethernet cabling. I still stand by the Nodes themselves as not being the problem.

Thu, 06/16/2022 - 16:08

#15

KE0RSX

KE0RSX's picture

@Chuck: I'll try that first.

@Chuck: I'll try that first. I was actually planning on shutting the camera off since I think it's the culprit. It's the only common item between both sites (same brand, same model, etc and it's a $120.00 PTZ knockoff camera that we got off of Amazon). I'm hoping this solves our issue with nodes rebooting as well as the repeater squelch tail (static burst) issue. The reason I planned on shutting everything down was to start fresh from a reboot.

The switch has been in place for about a year, along with the hAP ac lite that we used as a DtD hub. Before, we had three TP-Link CPE-210's on the tower with regular indoor cable. We replaced the cables with shielded, direct-burial cable and the CPE's with the Rocket 5GHz nodes. Plus put up the camera.I will try all of the suggestions in the post. Hopefully one of them works.

Thank you all for your advice. :)
Patrick.

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