A little over a year ago our repeater site experienced installation and activation of the Motorola Canopy hardware. I believe there are two 2 GHz antennas and one 5 GHz unit. These are each connected to a metal box with about 150’ of unshielded CAT5 cable which is routed in PVC. There are a total of seven CAT5 cables in the installation The Canopy antennas are mounted on wooden telephone posts at the site. They are located about 100’ from our repeater antennas with the “control” box for the Canopy system sitting on the ground on the east wall of our repeater building and roughly 3’ – 4’ from the repeaters, themselves. All connections to the box are through PVC bulkheads
The Loveland Repeater Association supports two repeaters on 147.195/147.775 and 449.575/444.575 MHz. Since activation of the Canopy system the repeaters have been experiencing severe interference that sounds much like the crackles, snaps, and pops that BPL on the ARRL web site sounds like. We have recently made recordings of the Canopy interference on both the 2-meter and 450 repeaters. The MP3 files can be accessed at:
http://www.cohampac.org/audio.html
The noise floor at the site has increased in excess of 20 dB (measured with calibrated equipment and calculated at 10-meters from one of the CAT 5 cables) due to Canopy broadband noise. Radiation is emanating from the CAT5 cables. Utility of both repeaters has been severely impacted by the Motorola Canopy installation and activation. We also have one report of a home subscriber to the WISP service provided by this installation through LP Broadband of severe interference to local Channel 6. This was confirmed with a spectrum analyzer.
Has anyone else encountered a similar problem(s) with interference from the Motorola Canopy system to RF communications in the HF, VHF, and UHF? If so, PLEASE share your experiences and ultimate solution(s).
With all due respect, I find that hard to believe. I’ve got Canopy installed
at several major repeaters sites with no noise issues. We have VHF, UHF and 900MHz at all those locations.
The antennas are built in to the units so RF shouldn’t be rediating from
the CAT5 cables.
If anything, the interference should be hurting the Canopy users if they’re
not using shielded cables.
What type of repeaters are they? Is it possible that it really is BPL and not the Canopy that’s interferring? BPL and Canopy ARE NOT THE SAME THING.
I would be interested to know if the interference goes away when you unplug the Canopy equipment. In the 3 years I have been using Canopy, I have never had ANY interference issues resulting from their installations at my repeater sites.
Dan
The issue that you are running into is that the Ethernet transmissions are emitting RF that is interfering with the VHF transmission. This has been seen at a number of sites and is not specific to Canopy. It is specific 100 baseT and sometimes 10 baseT transmissions on the Ethernet cables.
The same situation would be observed if there was a PC at each end of the Ethernet cable run and data was being transmitted across.
A few suggestions to help resolve the issue:
- use shielded CAT5 cables with shielded connectors, all properly grounded. In fact, Canopy recommends that shieled CAT5 cables be used in all infrastructure installation.
- encase CAT5 cables in metal conduit
- reroute cables so that they are farther away from the VHF repeater
- drop Ethernet negotiation down to 10 baseT half duplex.
- move VHF antenna farther away from Ethernet cable runs.
Any one of these suggestions might resolve the issue or it may take multiple suggestions.
Regards,
-ken