The PHY on the 100 radios has been known to be pretty noisy. I will
second Ken's suggestion. Set the radio(s) to Auto 10H/10F and see what
you get. Maybe a safer approach is to set your switch/router interface
to only negotiate 10H/10F (like the newer MT releases) so you don't have
to climb up and put in a default plug if anything goes wrong. One way to
test if it is the ethernet causing the noise is to leave the radio
powered up but bring down the link.
What power supply are you using? Possibly a switching power supply
putting noise on the cable? We're on a couple public safety sites and we
had a power supply causing their squelch to open up quite often.
Also, I don't think harmonics go down, only up. If their 150MHz
transmitter is a couple hundred watts, several harmonics could cause you
some ethernet errors, not the other way around. Like how ~100MHz
high-power FM sites really hurts ethernet. Nearly identical fundamental
frequency and high power is teh suck. Similar issue with your ethernet
and their very sensitive receiver.
On 7/23/2015 5:23 PM, Craig House wrote:
Ok we will give it a try but the repeater guy will not be back up
there to test for the noise until next Tuesday. Sounds like a plan.
------------------------------------------------------------------------
*From: *"Ken Hohhof" <af...@kwisp.com>
*To: *af@afmug.com
*Sent: *Thursday, July 23, 2015 5:04:02 PM
*Subject: *Re: [AFMUG] 900 fsk and interference with repeaters
When you say 2way, I think VHF, in which case maybe it’s the Ethernet
causing problems. We used to have this all the time with OTA TV low
band VHF before the digital transition. Have you tried forcing the
Ethernet to 10BaseT? Not losing anything with 900 FSK because it
can’t do 10 Mbps anyway.
Sometimes POE switching power supply noise can be a problem as well.
BTW, running coax up the tower is easier at 900 MHz than higher
frequencies because of the lower loss per foot of cable.
Looping the Cat5 several times through a ferrite bead could help as
well, but the fix we always used was 10BaseT. Or at least if that
make a big difference, you know the cause is the Ethernet not the radio.
psd
*From:* Adam Moffett <mailto:dmmoff...@gmail.com>
*Sent:* Thursday, July 23, 2015 4:48 PM
*To:* af@afmug.com <mailto:af@afmug.com>
*Subject:* Re: [AFMUG] 900 fsk and interference with repeaters
Yeah.....I was wondering if it's 450mhz or thereabouts
On 7/23/2015 5:41 PM, Work wrote:
Is the two way system on a really low band that would be a
harmonic of the frequency that you're on right now?
—
Sent from Mailbox <https://www.dropbox.com/mailbox>
On Thu, Jul 23, 2015 at 5:15 PM, Craig House
<cr...@totalhighspeed.net> wrote:
We have another tower that we have installed 900 FSK equipment
on that seems to be causing problems with a 2 way repeater
system. The noise floor on the 2 way system is 20 db higher
when the equipment is on. The down side to this is the tower
owner is the repeater owner and without his repeater his
business suffers and the need for the tower is gone. We have
in the past had this issue and ran coax all the way up the
tower to have only the antennas on top and it solved this
issue but I dont want to do this for a FSK 900 radio? So my
question would be, what are the odds that the new 450 900 mhz
that is only moments away from being released would work
without running Coax up the tower? I think this is an issue
with the processor in the FSK board not the RF @ 900mhz that
is causing the problem. What have others done about this. We
have another tower that seems to be on the brink of this same
issue as well and I dont want to completely pull off all 900
FSK but maybe I should? Should I just go to UBNT 900 until the
450's release?
