I reviewed the GXT900 on September 3rd and gave it high marks. I use these radios primarily at dog shows to communicate with my wife. Until recently, the shows have been either outdoors in warm weather or indoors. I used the radios outdoors in cold weather (20 degrees) for the first time today and discovered that one of the units will NOT TRANSMIT FOR MORE THAN 1-2 SECONDS in the cold. The other unit works well in the cold. After coming indoors (about 70 degrees) or warming the radio inside my jacket while outdoors, it transmits normally. The problem does not seem to be in the PTT button, since it clicks audibly and the transmission begins normally – it just cuts out after a second or two. I can reproduce this every time with the problematic radio (and it’s NOT the receiver section of the other radio). Any explanation would be appreciated.
UPDATE: I left both radios in the car with the outdoor temperature 18 degrees. In the AM, both radios were ice cold and NEITHER radio would transmit (as described in the first message) until warmed indoors. Bottom line: the GXT900 (or at least these two GXT900s) cease transmitting in extreme cold. I would not recommend these radios for use in very cold weather where they are exposed to the ambient outdoor temperature.
I need to try this with my models and see if I can duplicate this bug. Of course today, it is above freezing. I can charge them up and put them in the car tonight while I’m at work.
This is probably a battery issue. Seems like rechargeable batteries put out significantly less power when cold. Are you transmitting on high power? I would be interested to see if they will transmit on low power when cold.
There are also some rechargeable battery issues with the gxt850 radios (see my other post). Your problem may be related.
I had mine in the freezer for several hours. They still worked fine after this test.
The LCD was dim and slow, but thawed out fine.
Thanks for the replies. I tried the freezer test and found that I could reproduce the problem. Neither radio would transmit or receive after 2 hours in the freezer. Both were powered with fully charged Midland battery packs. After some warming, both radios would transmit, but only for 2-3 seconds and then cut out. At this point, I replaced the battery packs with fresh AA batteries and both radios worked well, After re-replacing the AAs with the battery packs, the problem resumed. Both radios were set to “HIGH.” After complete warming with the battery packs back in place, both radios worked well. So, this does appear to be a battery issue. I will probably use AA batteries instead of the Midland battery packs in the future, at least in the winter when outdoors.
I used the Midland packs in my test.
It does sound like the packs simply froze and then lost power… as can happen at times.
I’m glad to see your radios aren’t defective… I’m sure a load off your mind 
You might try using the medium power setting with the rechargeable battery pack. The range probably won’t be too much different.
I recently had a 10 mile communication (about 16 km) between a Cobra Li6700 on high power and a Midland GXT850 on medium power from hilltop to hilltop. At 17 miles (about 27 km) I couldn’t get through at all until I stood on top of some bleachers at a high school football field (no hills in the area). Communication was possible but very difficult at that distance.
I have noticed that higher power will improve the quality of the transmission (less noise) when you get further away or have more obstacles, but medium power might work better than you think.