HELP, we make Noise on fire deparment freq.

RouterOS Wireless Networking
1

I need help very bad

we are making noise on our fire deparment 76.450Mhz
But is not all the time
When we shutdown our 5Ghz system, it goes away
we have make a test, where the system is working a lot. no noise

we have RouterBOARD 532, with 4 Wireless (Atheros AR5213) card
ist all have ground, is in a seal metal boks.

Link:
Then we have a Link 5.1-5.8Ghz Integrated Router Antenna , RouterBOARD 532 connectet to the other board (Atheros AR5213)

when we install the system it was in pvc box, then we make noise
then we switcs cabels (internet/power) to shield cabels, and put the routerboard in a seal metal boks


we wil try to got 2.4ghz to see that solve the problems.
But we need to use 5ghz

What can the problem be ??
the board in the link, is not shield more than it is, (and can make the noise)

Hope someome have a helping hand, because the Fire deparment will get the pluck :cry:

2

532s have noisy power supplies, particularly using 48v.

Try changing to 18v, its supposed to help a bit.

http://forum.routerboard.com/viewtopic.php?t=2987

George

3

Shielding everything with foil should also help.

4

Thanks
But I need a solution thats works 110%
Have MT problems with other routerboards RB112, …
if not, we have to replace them

If that is a problem with MT hardware I think they have have to fix it. very quick :smiley:

5

I had a similar problem with a Deliberant DLB-2300a radio.

I did an install at a apartment complex and the building manager wanted me to install the CPE on the pole with the TV antenna that feeds the building. LOL
He soon asked me to move it because the thing was fracking up the TV signal.

I moved it about 15 feet away and the problem stopped.

I know this really doesn’t help but I don’t want you to waist money on new equipment and still have the same problem.

How many feet is there from the antennas you’re messing up?

6

I don’t now but about 20 meters
is in a 65 m tower, and we have the MT in 40 meters, its radio communication, tv antenna, satelite disc

but we have 400 user on, and if we dont find out the problem we go dead
it is the only place for us, or we have to raise a 60m tower

but I hope to hear somthin from MT support, I have mail them.

7

Is the 532 on the tower or down in the shack? If it is on the tower are you using shielded Cat5 cable? Have you tried ferrite coils on the the power or ethernet cables leaving the 532 box? Have you tried bonding all your grounds to a central point? With RF problems you just have to keep experimenting.

8

Thanks, but we dont have time to do experimenting, because the fire deparment will ban us fro using the tower.
Ther is som thing I will try.
the rb 532 is in the tower, we have special shielde kabel
we have ground all things, but we have not tried ferrite coils
do you have a link ??

9

Maybe you need a rb532p1 instead , it has no transformer onboard ( 12v only ) , it probably would be quieter.
Or remove the transformer and other components from the board you have if you have the tools/skill

10

If RF is radiating down your cables something like this may help.

http://mpja.com/productview.asp?product=15566+FL

Sorry for the slow response on my part.

11

Hi Chucka
Yes We have putting them on, we about 40m of cabel and the get on every 10m, then we hope that helps

12

You can also try:

  1. Changing the wired network speed between 10/100mbps - be sure the other end will accept this change

  2. Changing the CPU frequency of your Routerboard

I’ve seen this type of problem with 802.11b radios and on investigation with a spectrum analyliser it turned out to be the electronics on the circuite rather than the network cables or the radio its self

good luck

13

Can we change the CPU from winbox, do we have to switch jumpers

We have found out that is not our cables, but the HW

14

You can do it from Winbox, you will need to open a “New Terminal” (see buttons on left hand side)

It is probably worth upgrading the bios before you begin.

http://www.mikrotik.com/docs/ros/2.9/system/routerboard

15

hmm, that page in the manual is not very helpfull for the RB532

To upgrade firmware:

[admin@SF_AP] system routerboard> upgrade


To change the Frequencey:

[admin@SF_AP] system routerboard settings> set cpu-frequency=198Mhz

Or what ever, you can press TAB or TAB TAB to get the commands and options on the command line.

Once you have changed the CPU speed you then issue a “keep-frequency” command in the settings.

16

My solution to a similary problem was.

Go down to 12-18 volt on the RB532 and power direct from a car battery with an old battery charger without switching tech.
Then it will work. I was disturbing the VHF band in sweden. for a cabel tv company :slight_smile:

//Rickard

17

Hi
We We have power the board with POE, and that is max 18V

18

Do not use SWICHING power supply for POE !!!

19

What do jo mean with that :question:

20

We will try to use 12V with an car battery, I have to buy the charger / battery, what to buy. I have 1 112 board and a rb532 with 4 Wireless (Atheros AR5213) 3unit 400mw 1 65mw.
then we have 5 ovislink 5460 for our b/g user (switc to rb532 board) if it works. and the cabel from the battery is 45 meters. how big battery do we have to use