I have a problem that occurs with Mikrotik R52n-M radios I bought. After a period of time, the radios go silent and all connections drop. I have to reboot and then I can see the SSIDs and connect with my laptops and smartphones again but after another period of time, the radios go silent again.

I'm using x86 v6.11 on two different model computers for two routers. I have two brand new Mikrotik R52n-M radios and both do the same thing. I use minPCI to PCI adapters. The radios experience the same problem on both routers. One router is configured with two VAPs and the other doesn't have any VAPs.

All other radio versions I have work with no issues. I used them on the same miniPCI to PCI adapters and routers.

I wanted to upgrade to a radio that supports 802.11n. The Mikrotik R52n-M radios support 802.11b/g/n.

Anyone else have this problem? If so, what did you do to resolve the issue and why?

Here is an update and I'd like to find out if anyone else has heard of this?

As I mentioned, I had R52n-M radios that would stop transmitting, go silent, after a period of time. The only way to get them to start working again was to reboot the router.

I replaced the R52n-M radios with R2SHPn radios. The R2SHPn radios would not work, at first. What I eventually tried was to set the Tx Power to "card rate' and set the power down to 15 dbm. I rebooted the router and guess what, the radio started working.

If I raise the power back to 17dbm or 18dbm, the radio works for awhile but eventually will stop transmitting. I have to reduce the power back down to 15dbm and reboot the router to get the radio to transmit again. The radio does not seem to want to work again unless the router is rebooted.

Are these radios shutting down to protect themselves from burning up or something? I am using antennas made for 2.5Ghz. What is going on?

What power supply are you using?

These radios are used in an x86 computer.
I have two different types of miniPCI to PCI adapters.
I have two different model x86 computers.
I have two brand new R2SPHn radios that were bought last week. Both of them do the same thing.
I tried R52n-m radios and they would shut down too.
No combination work using the defaults but reducing the power seems to.

Any other radios I try work just fine but they don't support 802.11n. I've never had radios shutdown like this before, ever.

Power?

The R2SHPn uses 10watts max at 3.3volts. That is .33 amps.

The miniPCI to PCI adapters have a 3.3 volt regulator chip on them rated at 1 amp.

I don't think power is the issue.

I think I'm wrong. 10 watts at 3.3volts is around 3 amps

Hi rgraham,

In a DC watts to amps conversion, the current I in amps (A) is equal to the power P in watts (W) when divided by the voltage V in volts (V), i.e. I(A) = P(W) / V(V). So in your case you are right, it is 3.03Amps approx.

Did you get a spec sheet with the convertors? It might give you the thresholds for the PCI card. Also, maybe you can check what the x86 power supplies can pump out on the 3.3vDC output.

Rgds,
Mark.

I'm checking this out now. I am pretty sure now that not having enough amperage is the problem.

The miniPCI adapters I have regulate 5 volts to 3.3 volts but only up to 1 amp. This was to support older PCI slots that didn't provide 3.3 volts. 1 amp is not enough to run full power on these radios that will draw over 3 amps. When I raise the power, I exceed the amperage available, the voltage drops, and that is when the radio stops working.

There is a jumper on the miniPCI to PCI adapters I have that can be moved so the 3.3 volts is drawn directly from the motherboard, if you have a 3.3 volt PCI slots. Some older motherboards didn't provide 3.3 volts on the PCI slots.

How much amperage you can be draw per slot is manufacture specific for 3.3 volts, I read. There is no standard. I'll have to check this out. Maybe I will put a voltage meter on the 3.3 volt jumper, that can be moved, and see how far I can push the radio before seeing the voltage start to drop.

I have to find out what the motherboard can supply for 3.3 volts. I would like to run the radios at a higher power level.

Hi rgraham,

Just putting/placing the voltage meter on the 3.3vDC jumper probably will not be much help. You need to place an amp meter in line to see the current being draw in Amps and not the voltage in Volts.

Hope that helps,

Rgds,
Mark.

The 3.3 volt jumper that is on some of my adapters is for 3.3 AUX used for (Wake-on-LAN) capability.
The minPCI to PCI adapters I have are the 5 volt PCI versions, not for the 3.3 volt PCI slots.

There was not enough amps provided by the voltage regulator on the miniPCI to PCI adapters.

There was a voltage regulator on my miniPCI to PCI adapters that supplied the 3.3 volts up to 1 amp and the radios take more than that. I removed that 3.3 volt regulator and wired into the 3.3 volts available on the PCI buss. I wired from the 3.3 volt pins on the PCI buss, pins A21,A27,A33,A39,A45, to the circuit board pad that the output of the voltage regulator was soldered to. I have one type of motherboard I use that seems to be able to handle the current demand. I have one other type of motherboard that can not. So what kind of motherboard you use does matter.

So far all seems to be working fine.