Cold Weather Problems

Hey guys,

Winter has finally hit a lot of us and I'm having a lot of trouble with many of my ePmp 2.4GPS radios. Some have suggested this is a known issue in other threads, but I wanted to open it up for discussion.

I upgraded 8 of my Problem APs from 2.5  to 2.5.1 and then to 2.6. Of those 8 3 have completely died. One is showing Ethernet, but not replying to pings. The other two are showing Ethernet up, dwon, up down, but never ARP or reply to pings.

I fear I may be doing at least two climbs tomorrow in very unpleasent conditions. Any one have any thoughts on this matter or experience with this isse?

some of the radios do have issues with cold. the radios that you cycled can take up to ten minutes to warm and come back,  I PM'd you the firmware link.     going back to 2.4.3 or 2.4.2 can fix the problem as well.        we've noticed it only with force 110HP units and 2.4 GHZ APs

for me i found the issue on all epmp with gps on it. 5 ghz and 2.4ghz but 2.4ghz seems more affect then the 5 ghz one... 

we've had a few of the Force 110s with GPS have issues, but of the 60 or so regular 5ghz APs  w sync we haven't had any issues with them.    I'm sure its possible for them to be bothered as well i suppose. 

We are seeing cold issues as well.  Anyone have a link to the firmware?

here for 2.6.1 RC1 (fix cold issue)

use SMPX for NON-GPS and APPX for GPS Sync radios.

the radios that you cycled can take up to ten minutes to warm and come back

Just to add a bit of info to this, and to hopefully help clear up some possible confusion - there are two separate cold issues - but one is a problem and the other one is a feature.

So, the cold weather RAM problem has to do with the memory timing problems in cold weather, and that problem has been fixed in 2.6.1.

Separately from that, I've also read some misinformation on another product's forums about the cold startup feature. The cold-startup feature is is not a bug, it is a designed in feature, where (for example) the power goes out in the winter and a radio may be unpowered for some time in very cold weather. When most brands of radios are repowered in a situation like this, they will try to start immediately and (if it's cold enough) they will often probably just fail to start, or they might start but will cause component strain, or they will start, cause condensation and component failure. Cambium designed in a heater feature, so in this sort of situation where an unpowered radio has become very cold, the radio will pause it's startup, it'll kick on the internal heater, it'll heat the radio up to operational temperature, and then allow it to continue with a proper restart. This is a feature (not a bug) and it's totally separate from the RAM timing issue that has been addressed by 2.6.1 which is awesome. :)

I know most of you probably know all this, but since I have read on the other forums about the ''won't start up for 20 minutes BUG'', I thought I'd post here to make sure people know it's not a bug, it's a feature that Cambium put in on purpose, and it's awesome for us in cold climates.  :)

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So I have been able to install 2.6.1 on several of MY APs  many of the issues have been reolved.

The problem I'm still having is APs that won't even begin to boot. The Ethernet goes up and down every few seconds, but never fully boots. I grabbed two new APs, installed 2.6.1, and replaced the two I was having prblems with. SAME THING!! I know it can take up to 20 minutes, but after an hour they never booted.

As a last ditch I unplugged the radios from the CMM and plugged them into the power subbly that came with the APs and eventually they booted..

Any thoughts on why the CMM Micro won't boot the radios, but the PSU will??

Issac - we just experienced the exact same thing (almost).  We were powering from a SyncInjector at ~25-26V.  The ethernet link would go up/down/up/down/up/down all of a sudden, although we believe the wireless interface was still up.

It came back to life when we powered it with a 30V Cambium supply.

I'm wondering if the onboard heater has more stringent voltage or current requirements than the rest of the AP.


We recently ran into this issue as well. I noticed that the heater would not kick in on the tower, but when we pulled the units and tested on the bench no problems at all. I believe this may be a voltage issue as well. On the bench we had 6ft cables compared to 150-200 feet of cables to tower. We had another Poe that put out around 50 volts from other equipment we use. When we plugged the epmps into the higher output Poe they snapped out of the on and off cycle.  We also had a few updated to 6.1 -RC5 that would not come out of the rebooting until we plugged into the higher voltage Poe.