Any chance it’s a PIM issue? I think we all dismiss PIM as something vendors talk about and other people (not us) have to worry about, but I guess it’s a possibility?
Could be from your own equipment, or others on the same tower, like the FBI you mention. If you can get contact information for them, maybe they could shut their transmitters off for an hour to see if your problem goes away? If they’re not in ULS, is there a phone number on their cabinet or shelter at the site? We tend to be intimidated by the three letter agency guys, but the few times I’ve had business related interactions with the FBI, they’ve been fine to deal with, even if they do dress exactly like you’d expect from TV. At least if you know it’s a PIM problem, that might give you some ideas how to fix it. Maybe the 7 GHz with something sub GHz is creating intermod products in lower 6 GHz? If not on your exact frequency, maybe close enough to overload your receiver. From: AF <[email protected]> On Behalf Of TJ Trout Sent: Friday, August 8, 2025 1:46 PM To: AnimalFarm Microwave Users Group <[email protected]> Subject: Re: [AFMUG] 6ghz (lower) interference Thanks Tim! I hadn't considered that low level interferer to be a concern, I went ahead and temporarily reduced my channel size to move out of that space but haven't seen any improvement. Pretty convinced it's an external interferer but it's either not within the radios diplexers or it's some type of carrier scheme that the radio cannot detect (Tarana?) Anything with AFC shouldn't be an issue but who knows, I think the only solution is migration to a new band... On Mon, Jul 28, 2025, 1:32 PM Tim Hardy <[email protected] <mailto:[email protected]> > wrote: If that -85 dBm carrier is co-channel or within the occupied bandwidth, it could be problematic. Typical co-channel interfering level requirement is around -99 dBm. Anything higher than that could be causing some issues. On Jul 23, 2025, at 6:24 PM, TJ Trout <[email protected] <mailto:[email protected]> > wrote: Yes it's clean, only a tiny -85 carrier (link is -38 RSL) but I am starting to think that maybe the interfering carrier is not being detected by the radios integrated spectrum analyzer... Might need to do a secondary scan with an external device. around the time the radio started having issues the FBI installed some type of equipment on the same site, not sure if it is related but it looks like two sector antennas for land mobile radio? And also a 7ghz cambium link. I haven't had any luck in locating these transmitters in FCC ULS. On Wed, Jul 23, 2025, 1:04 PM Josh Luthman <[email protected] <mailto:[email protected]> > wrote: Did you do a spectrum scan? On Wed, Jul 23, 2025 at 3:55 PM TJ Trout <[email protected] <mailto:[email protected]> > wrote: Also only one side receiver is showing errors but the modulation is affected in both TX directions. SNR and RSL remain unchanged since install! On Wed, Jul 23, 2025, 12:53 PM TJ Trout <[email protected] <mailto:[email protected]> > wrote: So this 6ghz link is still acting up, connects at 4096 qam and demodulates to each lower order modulation step by step about every 1 second, once it reaches the lowest modulation it drops connection and immediately repeats the same behavior again. I've replaced both radios and performed spectrum analysis and found no interference. One side we replaced the DC power supply and the other side has many links but this is the only link misbehaving. Working with the mfg (aviat) but even they seem baffled at this point. Link was installed 5 years ago and performed flawless with no configuration changes since installation. Maybe the borg can help? On Wed, Jun 18, 2025, 10:15 AM Ken Hohhof <[email protected] <mailto:[email protected]> > wrote: Unlikely, but something that occurs to me is that if I remember correctly, unlicensed 6 GHz CPE radios are allowed to transmit at +30dBm EIRP while trying to contact the AFC, and then at +36dBm if given permission by the AFC. So it’s not like they can’t transmit at all without OK from AFC, or are limited to very low power like indoor CPE. I think they first need to see the AP, which needs AFC permission, so a total screwup seems unlikely. From: AF <[email protected] <mailto:[email protected]> > On Behalf Of Eric Nielsen Sent: Tuesday, June 17, 2025 7:33 AM To: AnimalFarm Microwave Users Group <[email protected] <mailto:[email protected]> > Subject: Re: [AFMUG] 6ghz (lower) interference Send me a PM with the coordinates and/or callsign of the receiver that's getting the interference. I'll run the site and tell you if I see anything in the general area that could be suspect. If the link continues to receive interference, like others said, you should run a frequency scan to identify the interfering emission and its bandwidth. If the bandwidth is 40, 80, or 160 MHz, that's probably unlicensed. Lastly, if the problem persists, you should report it through the AFC interference portal: www.afcoperators.org <http://www.afcoperators.org/> On Mon, Jun 16, 2025 at 4:53 PM TJ Trout <[email protected] <mailto:[email protected]> > wrote: One of our aviat lower 6ghz links started taking errors on one side, I haven't looked yet but I suspect it's interference from unlicensed ptp/ptmp gear, is this even worth chasing? It seems like I might be better off moving channels or bands? -TJ -- 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] <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
