I recently purchased more than 30 sets of these radios, which appear to work well, except for one problem. For some of them (~40%), holding down the PTT button sends them into a state of a flashing display during which they do not transmit. These radios do RX, however. If I switch the power to Mid or Low, this problem goes away. So I have two questions:
Has anyone come across this issue and found a way to resolve it with keeping high power mode?
What is the difference in wattage when I switch down to Mid power (how much of a reduction in range can I expect)?
It is perhaps a low battery sistuation. I will try to duplicate this condition with My Midlands by letting the battery levels drop. If they work fine on Medium, it is a possibility of not enough power. Try good AA alkalines.
Your range shouldn’t suffer much on lower power. Line of sight and obstructions has more to do with range than power on UHF frequencies.
I’ve had the exact same problem with one of a pair of Midland GXT-850 radios.
I measured the battery voltage (measured across the metal charging terminals on the bottom of the radio) during high power transmission. The voltage dropped from about 6.7 volts before transmitting to around 3.6 volts during a brief transmission. The effect was more pronounced as the battery discharged. The voltage would get so low that the radio would reset itself after the PTT button was released.
The engineers decided to use AAA batteries in the factory rechargeable battery pack. NiMH rechargeable batteries have a lower cell voltage than alkaline batteries. By using the smaller AAA batteries they could put five batteries in the pack and keep the voltage up around the 6 volts you would get using four AA alkaline batteries.
The problem is that the AAA batteries have considerably less available current (and therefore power) than AA batteries. The AAA batteries are marginal at best for high power operation. As a result, I rarely use high power. Switching to AA batteries should solve the problem.